A better "mouse trap" is available : rating system

I'm sure a few will be sceptical but a better mouse trap is definately possible when rating catamarans. As always the truth is in the middle and so the better rating system is lcoated somewhere between the European single numbers measurement systems and the Multi numbered yardstick numbers.

I tried to improve on the rating system by adressing as much issues as I could without complicating the rating system. Over time I listened to what sailors AND race organisers were asking for and tried to strike the optimal balance between the two. I also included preferences of both camps so that both have ground to accept the proposed systems over the older and arguable outdated Texel/ISAF and Yardstick systems.

Two years ago I tried to convinced the Texel rating committee to accept the proposals or at least include several mods into the well know Texel system but the effect was neglectable. I quite as advisor to the texel committee shortly after that.

I know would like to use this post and thread to explain the upgrade system to the world and hope to provide all the catamaran sailors with a more satisfying rating system.

I have not much trust in the established rating system committees simply because they are to much politically and emotionally attached to their old systems that have became stagnant as a direct result.

Just as with the Formula revolution it will again be up to the sailors themselfs to force a change or accept living with inferiour systems.

To proof my arguably big words I will use this thread in the comming weeks to present the upgrades and modifications and present a working system at the end. I will provide this system as is and free of charge although I will be very grateful when my imput is credited when using this system. If only to help me get into analyses and mathematical construction jobs that I enjoy and hope to be good at. At least that will give me some return on my time investment in all of this.

Last Note : I began to play with the idea to design such a new/upgrades system when some 4 years ago I was challenged to design a better system on the old Catsailor forum. This was often after lengthy posts made by Carl Roberts. I took the challenge and so here it is.

Regards,

Wouter

The project resulted in two improved systems :

First the NMBR system;

NMBR stands for New Measurement Based Ratings; This system is the most simple compromise between the wishes of both sailors and organisors and adresses the wished of both the measurement system fans as well as the Ameican/Australian sailors. This system is the one I think can bring the world together under one rating system setup. It is measurement based just like Texel and ISAF to cut down on maintainance work and to prevent rating creep. However it is fully intended to be alot more flexible than the current Texel and ISAF systems. It is intended to progress with the times. Afterall Texel was acceptably accurate in the 80's when all boats were very similar however it lost it accurateness when all kinds of new design came into play during the 90's. The Texel continued to ignore the changes and lost as a result. NMBR recognizes this and aims to prevent this from happening again.


Secondly the MBSR system;

MBSR stands for Measurement Based Simulated Ratings. This is actually more comparable to what yardstick systems try to do but fail at often. It takes know dependencies related to different setups and simulated back a rating on a set of parameters. This system is actually intended for distance races where normal assumptions underlining both Measurement as yardstick systems are not satisfied. No matter how you turn it both type of systems assume that a triangular course or a windward-leeward is sailed. This however is seldomly the case in distances races.

Each system shall be covered independently in this thread about a better mouse trap. They can however be made compatible.

The thing to remember is that the systems are constructs. They are based on logical framework, of some abstract level, but never the less their machines that can be altered or modified when that is so desired. Neither of them have a parameter regression or a statistical processing as the working core, meaning we administrators of these things understand how it works in detail and so their is no black art to confuse the sailors. OF course their fundamentals are based on various forms of statistical processing and dependency regression but only at the basis. Or more concrete example. The shape of the current texel formula can NOT be explained physically, the workings of Yardsticks system include many distrubances that are assumed to cancel one another out, simply because we have to assume that or accept that what we do is ill determined. Both NMBR and MBSR systems do NOT suffer from black boxes like that.

It is understood that even these improved systems are not perfect or even 100 % accurate. The desire for simplicity prevents that. However the only thing that really matters is that they are MORE accurate and MORE dependable than the current systems in use. That should be enough.

Wouter

Header post

Header post

Wouter and all,

Basis #1
Spin beach cats and non-spin beach cats CANNOT race as 1 class.

As funny as it sounds, down here, a trend ( by PRO's)to lump ALL beach cats into 1 class, spin and non-spin alike. Even when the non-spin and spin boats have enough entrants to form a class, by the regatta's published rules.

The POR's premise is, " they all have a Portsmouth number, don't they?" Of course, the spin boat skippers get real quiet, while the non-spin cat skippers fall over on the ground.

As clear as it appears to you and me, regattas dominated by monohull-minded officials cannot see it.

So, please Wouter, in the new rating formula, STATE IN BOLD LETTERS,

NON-SPIN RATINGS DO NOT CORRELATE WITH SPIN NUMBERS

Thank you.

I hope the Rolex Committee in St. Thomas sees this.


regards,
Bruce
St. Croix
USVI
X 17 normal

New Measurement Based rating Catamaran handicap system (NMBR)


The goals of this system is to provide the sailors of small catamarans (up to 22 foot , 6.70 mtr length) with a more dependable and generally accepted rating system. It's intended use is in open class racing on closed course regatta's.

The main characteristic of this system is that it is completely measurement based (Like Texel, SCHRS) and therefor does not require 'rating development time' for new designs as is the case with yardsticks. Nor does the rating numbers show any creep over time when good crews either enter or leave the class. An added advantage of the system is that everything can be explained on physical grounds. There are no more magical black boxes.


Back ground and correct use of the system

Lets be blunt, a rating system does not have to be highly accurate. Of course with sufficient effort and resources one can implement a very complex Velocity Prediction Model and get spot on rating numbers. However there are also two good reasons why this has not been done in the past even though the technology to do so has been around for some time.

The first reason is the system major design goal has always been that it must be practical in application. Complex system are quickly disgarded by both sailors and the race committees. Sailors don’t want to wait long for the results nor want to work with large confusing tables of ratings for their own craft. Race committees really don't want the hassle and delays that these complex systems bring with them.

The second reason is that a highly accurate system is useless in real life application. After a certain minimal accuracy the final scores hardly change. Typically the spread between crew ability in a one-design class easily leads to spreads of 20 minutes per hour over a complete fleet. This where inaccuracies in a decently accurate rating system will only account for offsets as big as 1 or 2 minutes per hour racing. This leads to the situation where the net result of a much more accurate system is only that one or two crews move one or two places up or down, not much else. Very often the top 3 listing doesn't change at all. Therefor; the challenge is to design a system that has sufficient accuracy and then concentrate on making it as practical as possible. Making it so to both sailors and race committees.

Why a new rating system at all ? Because the current systems are either impractical or have a fundamentally and unacceptable large inaccuracy. Several systems used today did well in the past but have lost accuracy due to increased variation between the catamarans of today. Comparing a Hobie 14 to a Prindle 18 is something else than comparing the same Hobie 14 to a rare, lightweight, cat rigged modern doublehander like the Marstrom M20. It is not that the old systems have deteriorated but rather that they are now required to cover a much more diverse fleet. Something for which they were never developped. To get this corrected is the responsibility of the new rating system

A point of note is that rating systems can be made relatively more accurate by making them less sensitive to factors beyond a Race Committees control. Such factors are a gradually changing wind direction or changing wind strength. Note that these impact negatively on a one-design class just the same. However in some cases it can be proven that an open class fleet is impacted more by these factors. A good trick is to group together boats of similar performance or setup. With sufficient participation a regatta can then be made up of say a spinnaker fleet. a low performance fleet and a singlehander fleet. A change in wind strength will impact differently on a spinnaker boat than on a singlehander but much the same on two spinnaker boats or two singlehanders. To maximize rating system performance in this way will always be the responsibility of the race committee and not of the rating system. However the rating system can still maximize the accuracy when rating a diverse fleet under relatively constant conditions and it should very much try to do so.

The hardest test is to accurately rate a fleet of 20 boats or less, as at most clubraces, here one is forced to group all makes together. However here we also arrive at some responsibility of the sailors themselves. As indicated earlier a one-design crew may finish anywhere between 1 second to 20 minutes behind the leader. In a small fleet of different type catamarans the difference between the first finisher, who finishes in 60 min, and last finisher is typically just over 30 minutes. This means that on average there is a gap of 1.5 minutes between each placing. With an rating system inaccuracy of say 1 minute per hour (2%) the chance that 97 % of the placings won't change at all with a more accurate system is very big indeed. Even of the crew that do exchange places, nearly all will only climb or fall one position in the final listing. Meaning that if you weren't in the top 3 to begin with that you most definately lost the race on skill rather than on ratings. That is under the assumption that the use system is accurate to 2 % or less. This is arguably not the case with the systems in use today.

From this we take away that there is at least a 20 minute spread in crew ability per hour and only some 13 minute spread between a Inter 20 and a Hobie 16 as a result of boat design. This should focus the attention of the crews on learning to sail better. However it must also be said this is only possible when a rating system satisfies the experiences on the water rather accurately. Not prefectly, but accurately enough so that any offsets are dwarfed by the differences related to skill. The rating system should at least do what feel logical to the sailors. That will go a long way to have it accepted by them.

This leads us to the design goals of the NMBR system.


The design goals of the new handicap system

-1- Must produce new ratings immediately as soon as a new production or one-off model is available.
-2- Must produces the regatta results quickly and transparently.
-3- Must be practical in use to both the sailors and race committee.
-4- Must adjusts the ratings according to input parameters that feel right to experienced sailors.
-5- Must strikes the best balance between accuracy, complexity and required processing during a regatta
-6- Must be relatively easy to maintain or fine-tune with time and increased understanding
-7- Must show no obvious or significant bias in any conditions to any design.

Significant, as used in point 7, is defined as 'must not contribute to the end result in a share larger than
1/10th when compared to crew skill'. Peferably less than 1/20th


Improvements

Older systems often used statistical data or a limited number of measurements to arrive at a rating. With the decline of catamaran racing and racing with smaller fleets, the statistical systems have trouble preventing rating swings due to influx of good crews as well as getting enough data points to make a dependable estimate for the performance. Measurements systems on the other hand still only measure a few parameters and implictely assume that all other aspects are the same between boats or do not matter. Of course the last assumption can not be supported anymore. There is too much to be done in order to remedy a statistics driven system. In addition, its working core is slave to a reality generating both good and disturbed data and that is to all-encompassing to be fully comprehended by an unskilled human brain. That leaves us with working out a new system using the concept of the "measurement based systems'. Despite its own drawbacks, this system provides the most accesible basis on which to base a new system. It is easily explained to unschooled sailors and its framework allows adaption to future developments. However, in order to provide a foundation to such an adaptation an ongoing statistical analysis of new developments will have to be performed . This is also needed to check wether the system is still up to the task. A measurement system may not be allowed to become stagnant and drift away slowly over time.

It was expressed by many sailors that the current measurement systems fail on points like correctly rating the addition of a spinnaker to a cat-rigged catamaran relatively to adding a spi to a sloop rigged boat. This is now a well understood phenomenon. Another good example it the problem of certain boats becoming relatively faster with increasing wind while others relatively slow down. Think of respectively a Hobie 16 and an Inter-20 in relation to a F18 catamaran. Current available systems do not adress these issues well enough and it is now possible to predict a likely handicap winner on basis of the wind conditions. The new system will correct these points.

An extra issue is the fact that some features of the system appear to be randomly applies or randomly applied. This is not good for the trust that the sailors are expected to put into a handicap system. Clearly a system that is not credited by the sailors themselves will go nowhere. This issue is also adressed in the new system.

Of course each system has its good points and its bad points so in developping the new system we have combined the good points and improved on the bad ones. And of course we have introduced a few new elements as well.

To cut down on required effort to get the system operational, the decision was taken to use as much of the parameters of the old systems as possible in a unmodified way. The end result is that we introduced 1 new input value and recycled all the known parametes and values into a new framework. When required this limitation can be abandonned and even more accuracy or simplicity can be introduced.


Important decisions

First, we have dropped the old standard class. Also known as the reference design. This design (class) was assigned a fixed rating from which all other ratings were derived. It acted as a pivot around which the other rating derived their (relative) meanings. This used to be the classic Tornado, that doesn't exist anymore. In other cases it was the Hobie 16 design, arguably unrepresentative of modern catamaran fleets. The new proposed standard is the Formula 18 class because of its large global presence and it expected domination in the future. Already cat sailors are basing their own performance to sailors in this class as there are always a few of them around. The F18 class is also very representative of modern catamarans racing as a whole. After all the foreseeable future looks like it will be dominated by formula classes.

Later in the project it turned out that the rating of the (new) Tornado class (double trapeze, spinnaker, bigger sails) is constant under the new system with the F18 standard. Ergo the new Tornado class may be regarded as sort of a second standard. The same applies to the Formula 16 class which actually intents to race doublehanders and singlehanders on the same course. This latter class may proof invaluable to fine-tune the ratings of the singlehanders to that of the doublehanded standard class. It is expected that these three classes together will provide a sound base which will produce dependable statistical data to proof or improve the rating system. Such key proving points (classes) are very important in keeping the system up to date and accurate.

Second modification involved the use of modest averaged adaptation. When a dependency was found to be present but insufficient data was available to quantify it really accurately then the concept of an 'centralized educated estimate' was used. This may sound inaccurate but it is actually a good way to improve on the accuracy while keeping the complexity of the system low. Compare it to the game where two people have to give a number between 0 and 10 and the one closest to the mystery number wins. One can choose to name 2 or 8 and be either really close or not close at all. An alternative is to choose 5 and be reasonably close whatever the mystery number may be. Of course, not choosing at all is assured to loose. Hence making an educated guess near to an expected average is always better than doing nothing. In the follow-up iterations the optimal point can easily and quickly be found. This binairy approach is the most simple and quickest way when using the very simple 'More' or 'less' qualifiers.

Thirdly, the parameter expressions were kept simple. An example, the number 1 may have been used in places where 0.98 would have been closer to the truth. However a formula with 10 parameters all containing 3 digits quickly becomes a very confusing expression. If using a single digit number only created an off set of a few seconds it was decided that this was an acceptable price to pay for reducing complexity and increase the ease of use. Remember that by creating the same offset in ALL ratings will cancel out much of the impact of such an offset. Nothing changes in the listing if all handicapped time results are off set by the same amount.

Fourthly, the model of the catamaran was kept simple. A single heeling force estimate is made for identical sail areas and luff lengths even though in reality there may be aerodynamical differences in the rigs. Examples of differences are : having a square top sail or not ; having a very low boom, having skegs or long boards. It is possible to include these differences and be more accurate but it will add a lot of complexity and will make using the system impractical really quickly. Think of what needs to be done when a crew decides to entlarge their square top ? The race and rating committees don't want this hassle and nor do the sailors. A difference was made were sufficient swing in rating was expected. An example of this is the way in which a mainsail and a jib contribute differently to a the heeling moment. A cat rigged catamaran with a given sail area will therefor have a different heeling moment estimate from a sloop rigged catamaran with the same sailarea. This while two different F18 implementations will get the same estimate. It is expected that the round-off error are far to small to constitude any serious threat to accuracy.

Fifthly, the ratings are split in two groups. One group gives the rating for below double trapezing wind condtions and the other group gives the ratings for above double trapezing wind conditions. In both groups a second rating is available for the spinnaker equipped version. This is a simplied version of the wind dependent ratings systems. It is adviced that when 2/3 of the fleet is double trapezing when going upwind that than the high wind rating group willbe used. NOTE, this can be dependent on the composition of the fleet. A fleet of A-cats with a few other singlehanders may qualify for this transition at a lower windstrength than a fleet of Hobie 16's with a few other doublehanders. It is left up to the race committee to decide which group of ratings is used.

It should be noted that the Race committee can make a decision for the use of either number on observing the fleet along. No wind measuring tools are required. Also the transition from non-trapezing tot trapezing is arguably the most important transition from one wind scale to another. Different designs diverge here a lot more than at other wind scale transitions. This both minimalizes complexity as make usage more practical while maintaining the most important performance related transition.

Last, it is strongly adviced that the ratings are used on closed loop courses. This maybe triangles. Windward- leeward loops or even rectangles as long as the point of the start is also the point of finish (by approximation). The ratings are derived for such courses. The new system allows ratings to be calculated for exclusive upwind, exclusive downwind and exclusive reach legs as seen in one–way distance races, however accuracy is expected to suffer a little in these applications. It was decided not to fully fine-tune the system for this application as that would add complexity disproportionally to the frequency this feature would be used. A specilized system can and will be developped for this specialized use. Strong grouping of similar boats (not from performance perspective but from the perspective of general setup) will greatly improve accuracy in these applications although it is understood that the ratings will be less accurate than when used on closed courses.

Wouter

You are completely right and I will give such a statement more prominance in the final wordings.

Still, the NMBR system allows to rated the two more equally to eachother. Simply by the fact that when using to rating numbers, one for sub trapeze weather and one for trapeze weather, we can assign a heavier hit to a spi in one of the two ratings thus approximate the swing in performance difference more accurately than a single number system can.

It is not perfect but it is already a step up from the single numbers Texel and ISAF systems

It is also a step up from yardstick as experiences gained in one particular class of catamarans (F18 ? to say H16's) can then be easily extrapolated to all catamarans. Also the one with small or inactive fleets.

Please keep the suggestions coming.

I think I have designed a better system already but I KNOW it can be better still ! With your help we can make something really good

Wouter

Again I remind everybody that the NMBR system is a construct using the foundamentals of the Texel and ISAF systems. Used these as a starting point to facilitate acceptance. A complete new formula would be better but could probably be too much change in one go. If it isn't then wait and read MBSR thread later.

The issues

-1- Single handed cat rigged boats like the A-cat, M18 are rated to harshly. Some lightweight double handers are so too (M20)

-2- Cat rigged boats with a spinnaker are rated wrongfully against sloop rigged boats with spis.


There is ample anecdotal evidence for both points and even some dependable evidence. However we must all realize how difficult it is to get good dependable data. This is also the achilles heel of the yardstick systems. One really needs to do alot of pre-processing to determine wether a race result is dependable or not.

But what we DO know is this.

Texel and ISAF are relatively accurate when rating middle to heavy weight cat rigged cats without a spi to middle to heavy weight sloop rigged cats without a spi. Afterall this was the data set on which both systems were regressed. Say the span P16, H16, Dart 18, P18's, TheMightyHobie18, nacra 5.2, nacra 5.5, P15's H17 that sort of stuff.

It is a well known fact that sloop rigs are faster around a course when no spinnakers are used even though they difference may be rather small on the upwind leg itself. But only when the right balance is struck between the area's of the main and jib and when the same mast lengths are used. Things maybe different when one of these conditions is not satisfied (A-cats ?).

Both Arvil Gentry and Marchaj show in their respective works that adding a jib has the following effects :

-1- The suction zone on the main near the mast is disturbed leading to less drive produced by the main. This shaves of the low pressure peak. It also prevents the main from stalling easily resulting in a forgiving flow over the main. So it produces less drive BUT is more constant and stable doing so.

-2- The updraft of the main and the low pressure zone above the main result in the jib experiencing extra low suction on its lee sides at reduced apparent angles of attack. At a right balance in area's and slot width the jib will produce twice the force per area as the mainsail.

-3- When going upwind the main must be pulled more inline with the centreline of the boat and the boat must be pointed a little lower.

-4- When going downwind the boat can be pointed lower and the sails stall less easily at these high angles of attack.


If you run the numbers on this you'll quickly end up with a intepretation of the situation where

-1- Where the looses of drive on the main equal about 1 times the area of the jib leaving just 1 amount of jib area to produce extra drive. As a rought but relatively accurate measure.

-2- The factors work against eachother on the upwind as good as cancelling one another out.

-3- The factors work together on the downwinds making the sloop superior here.


Often the sloops carry relatively more area than a comparable cat rigged boat and so the sloops may often be a little faster on the upwinds as well. However we'll get to that later.

Obviously the main benefit of the jibs are found on course that are not upwind beats, although some benefit may still exist there. When a spinnaker is fitted to both boats the spinnaker takes care of most things the jib did. It prevents the main from stalling too easily and provides a large skewing of the apparent wind the main experiences allowing the boat to be driven deep. The jib has almost lost all its benefits except for the small upwind gains.

The problem with Texel and ISAF is that they keep regarding to downwind benefits of the jib as independent of flying a kite. This is arguably very wrong and most sailors know this from personal experience.

I refer to Tornado Alive comments for more data on this :

http://www.catsailor.com/forums/sho...6986&page=&view=&sb=5&o=

He gave us some great data on the comparison. I noted it down and research how it compared to what the theory said. It seems the two are pretty close together on this.

Therefor the remedy is quite straight forward.

An example :

Take two identical boats with equal size cat rigs and add a jib to one of them. of about 25 % size than the speed gain is as is currently predicted by Texel. Note how Texel and Yardstick system seem to converge on most boats, suggesting that Texel does do a few things right : I refer to Sam Evans for more info :

http://www.catsailor.com/forums/sho...8033&page=&view=&sb=5&o=

So lets keep this feature. Now if we add a spinnaker to both boats than the speed increase due to having a jib as predicted earlier reduces. A good "averaged estimate" is that 2/3 rds of the gains are lost because both boats now use a spinnaker.

We can therefor roughtly compensate for this by reducing the jib area to a fraction of what it was when both were
sailing without a spi. This fraction will only account for the gains found on the upwind legs. Finding this fraction is key but not really that difficult. I have used a constant I have matched with various race result in the example version of the system, it seems to predict performances well.

This correction has the effect that all sloop ratings remain unchanged (bulk of the raced boats) and also leaves the cat-rigged cats without spi rating the same to their non-spi sloop rigs. The only ratings that are impacted are the cat-rigged cats with spis which are definately a minority at this time and are relatively new to the game. Minimal impact for a significant improvement.

In effect we issue a larger speed increase to the cat-rigged setup when they add a spinnaker than we do to sloop rigged boats adding a spinnaker.

The modifications is simple and easy to implement. While still leaving the spinnaker modification independent so we can modify that one to make the comparison between spi and non-spi boats more accurate.

Wouter

Arguably both the Texel and ISAF systems use of only one rating number for accurately predicting performance over the full spectrum of wind strengths from 3 knots to 25 knots is a big ask. This is especially problematic when looking at spinnakers.

On the other hand the average DPN of yardstick in no better in this respect and many Race Committees dislike the 5 individual ratings that some yardsticks use. It requires much more effort from their part to measure the right wind speed and it makes rating calculations more cumbersome. Also in principle the ratio between different ratings numbers is surprisingly constant while the individual numbers vary. This is hardly effective. Alot of trouble for not much gain. Add to this that you need a minimal amount of data for each group to make an accurate regression and you'll get the picture of the work involved. It in no wonder why many RC just use the default numbers and be done with it.


The proposel to solve this deadlock is to have two rating numbers instead of 1 or 5 or more. 2 allows more freedom to improve accurate prediction for arguable very different conditions (trapezing and non-trapezing) and is alot simpler to use and maintain than 5 numbers.

Arguably designs will really only differ in performance on the threshold of going from non-trapezing conditions to trapezing conditions. It is the transition from always sailing under maximum achievable power to sailing under maximal controllable power. As a result there is not much to be gained to sub devide these two very different regions in more sub groups. So lets take the transition that is really important and forget about the rest for sake of ease of usage.

Also it is alot easier for a RC to determine which rating they should use just by looking at how many of the boats are trapezing. If this ratio is less than halve, you use the low windspeed rating, if it is more than halve you use the high wind rating.

By dividing the performance predictions in two groups of numbers we can also compensated FAR more easily for the swing in performance experience by singlehanders and spi boats when the transitions from sailing in light winds to heavy winds.

For example : the singlehanders and spi boats will get relatively faster ratings in the light winds group when compared to their ratings in the high wind groups. We can split any offsets that may exist in halve using this setup without really increasing complexity of the system used.

There is also a lot less potential for conflict. Either halve the fleet was trapezing on the upwind or they weren't.

For further details I refer to the posts about the individual mods.

Wouter

We all know that changing conditions impact differently on spi boats than they do on non-spi boats.

We will never be able to fully compensate for that unless we are willing to use a lot more complicated systems.

However we can much reduce the offset that we percieve in the current systems.

Example :

Spi boats tend to witness their largest gains, relative to non spi boats, in 5-12 knots conditions. This would largely coincide with the non-trapezing group of conditions. Above 12 knots of wind the difference decrease, minimizing at the far end of the scales (25 knots). This is arguable a constantly changing curve spanning the range from 3-25 knots. Approximating this actual behaviour by two horinzontal lines (averages in their own segments) is always better than to approximate it with just one horizontal line over the full spectrum.

By decoupling the spinnaker hit in the trapeze and non-trapeze segments of the windspeed we arguably cut the current ofsets in halve.

It will still be not perfect but yet alot better than we have no. Hopefully, probably, enough to get good ratings for club races were there aren't enough boats to group spi boats with spi baots and non-spi boats with non-spi boats.

In the working example I will provide later I have chosen, on data available to me, to hit spi boats harder in the sub trapeze conditions than they are in the trapeze conditions.

Wouter

Double handers and single handers :

The split in rating numbers between trapeze conditions group and a non-trapeze conditions group also allows us to correct the issue we have with rating singlehanders accurately with doublehanders.

There are many reasons why a singlehander generally performs better in the light stuff than in the strong stuff. We can't not compensate for them all for that would make the system to complex to use comfortably.

We can however take a few big important factors and correct for them thus arriving at much smaller offsets then before. Offsets that could well be to small to matter anymore when compared to sailor skill.

Beyond a doubt the most understood and arguably the largest factor in this is righting moment when compared to heeling moments. We have seen 18 squares clean up at Curacau when doublehanded while seeing singlehanded 18 sq. being left behind. There is one thing that is different between these boats. The same experiences are found in classes that sail their boat in two modes like the Taipan 4.9's. Lets use that experience.

The second biggest factor is control. It is just alot harder for a single hander to control and tune his boat in the heavy stuff than it is for doublehanders. Especially when flying a spinnaker solo as well. This factor can easily be included into the system by a weighting factor. That is in addition to the righting moment / heeling moment compensation.

There are certainly more factors as well but arguably the net gain that compensating for these can give are much reduced.

For arguments of simplicity I have decided to stick with these compensations and see if any others are still needed in the future. I do not expect that to happen. Certainly with these two compensations we will have sliced the offset to a fraction of what they were before.

Also the good part is that the Texel system contains all the data needed to implement these mods except width. For this reasons these mods are frightingly simple to implement. And also easy to maintain.

To calculate the righting moment / heeling moment ratio we use a simplied formula that contains known and noticeable offset with regard to reality. However it can easily be proven that these offsets are about the same for all designs and therefor the ratio's between designs are largely unaffected by that.

Example :

When taking a ratio of two numbers that are both 10 % of the mark and equal of sign than the ratio itself is only about 1% of the mark. Therefor you need not be very accurate in the base numbers as long as you can garantee that all offset are similar sized and have similar signs. That can be proven.

Proposed :

Heeling moment estimate = mainsail area * 1/2 * luff length main + jib area * 1/3 luff length main.

Righting moment estimate = weight boat * 1/2 * width boat + weight crew * (width boat + 1 mtr)

Notice how all input data is available in the Texel rating handicap system with the exception of the width.


In order to achieve aour accuracy we need to assign a reference design. For that we use the Formula 18 class.

This gives the F18 class a flat rating over the full spectrum of the wind speeds. Arguably a benefit in itself.

Wouter

The construct of each rating system is based on relative performance of each boat to a single reference. It is not required that such a reference is an actual design or class but that does have its benefits.

The old standard was 100 and was assigned to the Tornado under Texel although the true reference was the H16 at 116. The number 116 was taken because that was the numbers use for the H16 in an older rating system. Such are considerations of legacy. Sailors soon forget to origins of such things and therefor following up on legacy benefits is useless.

Yardsticks in general use funny numbers. Often somewhere between 50 and 80 or between 110 and 160. Such choices result in unnecessary calculations and also in corrected times that have no meaning.

If a design with rating of 70 sails for 60 minutes and is corrected to 42 minutes and looses to a boat with a 41 minutes corrected time many sailors think that the first boat had to sail 1 minute faster to win.

This is wrong as 41 * 100/70 = 58 min and 34 second. Or 1 min and 26 secs to slow to win. An increase of 50 %

It is MUCH MUCH smarter to assign a rating of 100 to the most prolific design. Arguably this is, or will soon be, the Formula 18 class.

Than NO handicap calculations need to be performed on the F18's, their elapsed time is also their corrected time. Less potential for errors as well.

In addition a 110 rated boat sailing 60 minutes with corrected time being 54 min 33 sec; that was beaten by a F18 coming in at 54 min, had only to finish at 54*110/100 = 59 min 24 seconds to win. Or 36 sec faster. As you can see this very closely approximated by the 33 second in the corrected time results.

So keeping all ratings as close to the reference of 100 is very beneficial. Centering this rating 100 among the group of boats most often entered in races makes comparison alot more easy to both the sailors and RC's. The F18 class is neatly centred between the F20, Tornado's and A-cats on one side and the bulk of the (older) 16,17 and 18 footers on the other. Neatly being defined here as being proportionally closer to the classes that will see most boats enter => F20's, Tornado's, F18's, F16's, A-cats and the faster Hobie's and Nacra's of the past.

For these reason choosing the F18 as the reference class has many advantages. And therefor we choose to do so.

Wouter

Wouter,

Very interesting reading. I will read it again after a less stressful day at work. However, I have one immediate concern :



F18 is a box rule, but a development class so the boats should get faster over time. Witness the difference between an old Dart Hawk and (say) a Nacra F18. You are not going to win any races on the Hawk, yet they rate the same in your proposed system.


The only way to have a boat that has a flat rating or 'core rating', is to use a boat that has totally strict rules like the Dart 18, Dart 15 or Hurricane 5.9. These boats will only get faster as people learn to sail them (which I would suggest has now happened - the only speed gains will be via new techniques such as wild thing, or the adoption of new sail cloths or build techniques).

Sorry for the O/T but,

You don't have a significant other in your life do you?

(either that or you never sleep)

Hi scooby -good on ya wouter -good beginning -

Historically rating systems have never lasted without being rethought and revised in different forms periodically ,-the best being one with the greatest simplicity able to renew and change with changes in the craft themselves over time.

Agree w scooob and will also wait for a less stressfull work day and be brief,-or is it holiday stress already ?,

to answer your question scooby ,- think what wouter meant in using the F-18 as a benchmark of sorts for rating is not a specific F-18 cat design but instead the measurement parameters that form the F-18 class used as a common model or benchmark of comparative speed.
Conceptually for consistancy and fairness in rating it is important to comprehend all craft as design measurement based rather than a specific boat by brand or class with huge variation in class brand rules ,-it only leads to inconsistancies .

Wouter has some great concepts in the attempt to rethink and update a design measurement based rating rule ,-

My 2 cents currently would be for the development of a combination rating system that would use the current yardstick pn with its attempt to equate real time to distance traveled in windspeeds in that same scale and familiar numbers , but used as a correcting factor to design measurement based dirived numbers though in more simplistic basic formula than Wouter is beginning to describe. Taking the approach of design measurement rating only historically leads to reinforcing current trends in design, thus the need for only basic definition in the design measurement aspect of L W SA plus beam and basic crew spin jib relativism ,--adding a yardstick system in combination should correct any major errors or omissions in the vast array of variables in design and wind seas conditions from there much better than either rating system does independantly as per currently used.
By using both systems they could both be simplified greatly and compliment or correct one another and would certainly become more accurate if adopted internationally providing more verification of the yardstick aspects in larger numbers ,--along with some added thoughts in ranking racing sailors in basic skill levels to correct this aspect further .
The simplification of the design measurement portion would be from the reliance on the yardstick aspect to compensate lesser design features that historically make design measurement rating systems counter productive by penalizing excellent design and thus to design progress and creative development. A design measurement rating system only in an effort to compensate all design variables makes them too complex to comprehend ,-the end result being a complex partial effort at total design annalysis subject to differences of opinion in design values in the equation.
There are numerous other reasons to develop a combination rating system that become clearer as it is thought through.

Outlined ---the combination rating system would not use the rated formula and proceedures in determining weight length or sail area ,-a simple direct boat weight -o a length -and sail area used ,-in a base equation ,
-Sounds like your working through proven proportional factors added for spin -non spin -jib -main only sail plans and single or 2 crew variables ,--this would keep it simple -and again the yardstick added to this as compensation for lesser design variables at a correcting percentage should be more verifiable over time with larger input sources internationally and a ranking system for racing sailors to compensate skill level unknown to some extent of the yardstick aspect .
The model end power formula of Texel similarly used but now in very simple form easily understood and calculated .
Think the end number factor in the power formula could be scaled to corespond to the 5 windspeeds currently used in Pn rating . Porportional aspects as to the division of length weight and sail area in design are established though some would state sail area is over emphasized in the equation . Again the correcting factor of the current yardstick system applied as a percentage factor should compliment the design measurement basis ,-there would be no need for the one size fits all approach modification factors currently used in Pn being replaced by actual sail area L B W measurement base numbers .

This basic approach in outline may be worth considering as better alternative ,--hope this is constructive and helpfull ,and also inspires others to think though an improved rating system that may be adopted internationally .

Happy Holidays
Carl

Lets just say that I need more sleep than most people, that I'm spending (losing, wasting even ? ) more time on a woman than I think is healthy, But that when I think things throught the pieces fall into place pretty quickly. In the past it would always end in headaches but I've become more skilled in taking the exit before I hit the wall.

Besides, it is simply a waste when it is doing nothing on my PC (or in my head) so I'm pumping it into the public domain and hope I give something back to cat sailing.

A man can dream can't he.

Wouter

A few answers that may either confuse you are come across as conflicting. However they are valuable enough to full understand.

From a measurement point of view even a strickt One-design class is a box rule. The whole idea behind a measurement based system is that of a box rule. The fact that Texel and many Yardstick converge on the same ratio's between boats suggests that the boxrule approach has merits.

With regard to the Dart Hawk, I think this design is still one of the better F18's around. Put a new updated set of sails on it and go ! I think that Dart hawk was victomized by the "bad perception virus". Its sales declined rapidly after the pounds rose sharply half way through the 90's. Then sailors assumed that the decline in sales was caused by the dart hawk being uncompetitive. Of course if sales drop you won't have as many boats in the class and then when Hobie starts buying away all the top crews than more and more people start to BELIEVE that the Dart Hawk is an uncompetitive design. Than it starts to feed on itself. I still think that the Dart Hawk is still one of the better product in F18 land. Just need to get the modern cut sails on that boat.

You refer to a difference between the Dart Hawk and nacra F18. Can you point me to data suggesting this ?

Dart 18, Dart 15 and H5.9 are simply to small as a class to act as reference classes. Furthermore only the Dart 18 has some international presence but only in Europe. Then of course the Dart 18 production will be discontinued in 2005 and it is badly situated in relation to other classes. Why use dart 18 as a reference when this design makes up less than 5 % of the fleet in all European regatta's with the possible exception of UK events. You will only get very very limited comparison data this way.

Also all the good crews are sailing in difference classes.

Also the Dart 18 design (and so to the Dart 15) are a far cry of being representative of the designs that currently dominate catamaran racing.

Last but not least; I see more merit in having a large, but less strict defined base to extract data from than a very small base of high restricted class. I can easily average out errors present in large block of data but I can't do that in very small blocks of data.

In simple word, from one perspective the named class maybe better as a reference. BUT when viewed from several perspectives the Formula 18 class as whole cleans the bank. Arguably a rating system can not be based on a single viewpoint that will make it very sensitive to errors and also very inflexible.

Sorry,

However I very much appreciate your input.

Wouter

I have personally a dislike for unsubstantiated modifications to any rating system. This means any adjustment for an old boat society (dead boat society) rating that is not specified as a general rule.

For example under the current texel system the Dart 18, Prindle 16 and Hobie 16 get their ratings upped by 1 point because somebody in the past decided that that was necessary. Why these boats and not others, what was the reason for this mod that was never specified in public ?

I can agree to such modifications to outdated designs to compensate for their relative backwards movement because the newer boats arguably have more refined features. However the selection proces needs to be general and verifiable.

Surely a case can be made that asymmetrically hulled designs like the P15, P16, P18, H14 and H16 suffer from not having boards or skegs. The idea behind the asymmetric hulls was an interesting one but we now know that it produced worse performing boats to symmetrically hulled ones with skegs or boards.

Therefor I propose that a list of 5 features (or lack of such features) is specified and that any design satisfying at least 3 of these features gets 1 or 2 points added to its rating.

I'm thinking off.

-1- Cat has assymetrical hulls without boards or skegs
-2- Cat has a mast unsupported by diamond wires or extra shrouds
-3- Cat has a pinhead mainsail
-4- Cat doesn't have a downhaul system nor a mast rotation system that can be continiously adjusted
-5- Cat doesn't have a smooth (rounded) transition from its sides to the deck (deck lips as on H16 and P16)

All these features pretty much add extra drag to the platform or limit sail control to such an extend that the rig is producing drive less efficiently than more modern cat designs.

This list effectively gives :

P15, P16, P18
H14, H16
Dart 15, Dart 18
nacra 5.0 (not the newer nacra 500) and Nacra 4.5 (not the newer Nacra 4.5

all an extra allowance on the ratings. I'm still debating wether this should be 1 or 2 points.

I do not favour or propose to have a statistical alogarithme produce offsets on calculated ratings. This is not verifiable nor easy in use. Also you get continious swings around a base rating depending on freak occurances in race data. Also this is sort of a black art and I'm not willing to saddle any rating committe official with the endless bickering that this so easily can cause.

Please note that statistical analysis may sound dependable and easy enough but often it isn't.

Example : A rating committee member when a race has been held under sufficiently constant conditions. Steeple chase 2004 contains very undependable data because of that freak low tide. A particular good race for the M20 in NL in 2003 was found to have contained a narrow wind band some 2 km out of shore that the M20's found together with one I-20 while the others tacked upwind closer to shore. Incidents like these very much skew data that very easily can cause an errornous swing in ratings. Checking all this is a [censored] load of work, I know because I don it. It involved number crunching and possibly phoning up participants to find out why the data does what it does. If anything this should be done on the background and no automatic link should be made to the rating systems.

Again when a large block of data over various class and events suggests that a general modification is off the a modification should be made, but never when such a thing happens in an individual case with a very small amount of data.

Simply put It is also very weird when say an F18 shows some exceptional behaviour that is not reflected in the behaviour of other comparable catamarans. Therefor all things are better incorporated as general rules. This may leave som inequality in the system BUT by far in most cases these are neglectable in magnitude and to small to sacrifice stability and simplicity for. Remember the less then 1/10 th of the end result threshold.

Nor am I sure such statistical systems can be made to work effectively. I wouldn't know how and I know some stuff about statistical and probability math.


Wouter

I was just using the box rule as apointer to the fact the boats evolve and so that they get faster, so making a moving target the focal point does not appear correct to me.



Does it matter that there are only 8000 Dart 18's and 2000 Dart 15's (approx) in the country. OK, if you don't like the Dart, use the Nacra 5.0, 5.5, 5.8 and 6 ?

The dart 18 is not being discontinued and neither is the Dart 15. The Dart 15 Class association in the UK now 'own' the designa and the boat is being re-named as the laser centre no longer have involvement. The D15 will be made in Sought Africa starting sometine in 2005.

>>I was just using the box rule as apointer to the fact the boats evolve and so that they get faster, so making a moving target the focal point does not appear correct to me.


I do understand that however, there are other factors as that keeping adding points to the F18 choice. It is like choicing a car. It is wrong to only look at the retail price. Before deciding to buy one you also look at things like fuel efficiency, availability of spare parts, and the cost of them, Ensurreance cost, the amount that particular drops in value each year, etc. One particular care beat all others in one aspect BUT fail to convince in the others. Such a car will not be bought often.

It is the same with the reference benchmark. You look at only one issue not at the framework of several different issues. I invited you to do the last and determine how you think the Dart 18, Dart 15 and H5.9 classes stake up to the F18 class ?

In addition to that ; there is one very important thing in choicing a reference class. It must provide a large basis from which the take data and gain insight. We all know and race agains F18's. Currently there is not a single design that doens't race against F18's in a handicapped fleet in the world. If we were to choice the Dart 15 than how would we gether data on the Taipan 4.9 for example. I have never seen a Dart 15 ever race against a Taipan 4.9. Actually same applies to the Dart 18 and H5.9. This single issue alone makes a choice for these classes as a reference class unattractive. More strongly I think the original 100 rating class, the Tornado, is to thinly spread to act as a good reference class. There is simply not enough dependendable tornado crews around to gether data on all other design. Again how to rate US designed boats like the Isotope when it is rare to see tornado's racing in US events. And if they do than the comparison of the Tornado crew can not be averaged out of the Tornado fleet making comparions very dependent on the particular ability of that single crew. THIS caused larger errors than say a benchmark fleet of 5 to 10 F18's where the average F18 performance can easily be determined by averaging the F18 results of the first halve. Sure their will be differences between the individual F18's but these are quickly reduced to neglectable amounts by grouping their data. Then we are only left to investigate the crew ability of the crew sailing the rare, Isotope, Taipan, F18HT or other boat.

Again there are more considerations like discarting the need to do corrected time math on arguable the largest fleet in all handicap fleets (F18's) but the above reason alone itself places he D15, D18 and H5.9 low on the list.


Dart 18, Dart 15 and H5.9 are simply to small as a class to act as reference classes. Furthermore only the Dart 18 has some international presence but only in Europe. Then of course the Dart 18 production will be discontinued in 2005 and it is badly situated in relation to other classes. Why use dart 18 as a reference when this design makes up less than 5 % of the fleet in all European regatta's with the possible exception of UK events. You will only get very very limited comparison data this way.



>>Does it matter that there are only 8000 Dart 18's and 2000 Dart 15's (approx) in the country. OK, if you don't like the Dart, use the Nacra 5.0, 5.5, 5.8 and 6 ?


No it does not matter. And the same counterarguments can be had against the N5.0, n5.5 and others. There are simply not enough of them racing internationally. Also the skill included in these classes is way below the level in the F18 class at this time. over 100.000 were build of the Hobie 16 but even that is not a good benchmark when looking at all considerations. It's participation on open class handicap racing is declining and the setup is too much dissimilar to the modern designs that you will hand yourself an awkward benchmark. It is more and more becoming a class for recreational sailors and it is not even the largest class anymore in events like Texel. Well, at least not in the way the F18 class is. I know this can be a hard pill to swallow down, but this is not a contest of which class has the most tradition or deserves to become the reference class for reasons of history. This is a contest of which class satisfies the most demands that are linked to being a reference class and does so for at least the next 10 years.


>>The dart 18 is not being discontinued and neither is the Dart 15. The Dart 15 Class association in the UK now 'own' the designa and the boat is being re-named as the laser centre no longer have involvement. The D15 will be made in Sought Africa starting sometine in 2005.

Okay, I have my info and without being disrespectful I find signs that the Dart 18 class is being reduced in importance. Prindle 16 classes and others like the Nacra 5.5 and Nacra 6.0 already went down that route and there classes have been disbanded. In effect there are no active Dart 18 classes in the USA, Aus and Asia while there are active F18 classes there. If this is to be an international rating system than surely we must find a reference class with an international presence.

Again I wish to underline that I mean nothing disrespectful by any of these comments, it is just that in a broad spectrum a choice for the F18 seems to be strongly favored over the named alternatives. Thank you for your comments.

Wouter

Wouter.

I totally disagree that in order to make the rule work you can choose any class that is a development class.



I agree with you, but my reason for objecting to the Tornado is that it is/was a development class (and the single wire tornado is now almost a non entity and so may actually be getting slower as all the good boats are converted to T2001’s)

Do you actually need to have a focal point in the rule, once the basic numbers have been calculated……? Boats speed will change as they are developed (F18 will get faster, Dart 18 will stay the same)

I understand that at this point in time (to establish the rule) you need to start at some point, and test your rule.

Ie, the rule must ensure that the following results come out from the rule (and many others too)

Inter 17 is slower than Inter 17R (F17)
Tornado 2001 is faster than F18
F18 is faster than I17

And so on.



But the rule you propose is measuring theoretical performance, not real world (crew dependant) performance. ‘Driver skill’ is not relevant.

Or does your rule propose to give boats that are di8fficult to sail (ie have more sail controls for example) a more favourable handicap ?

BUT, I applaud you in trying to come up with a new method. Just don't tie it to one class as the Texel and SCHRS have been once you have a formula.

I don't read all these rating threads, because I don't understand them. But I do have questions:

How many ratings systems are currently in use by beach cats, and where is each used? For instance, is the Texel system used throughout Europe? Is the Portsmouth system used anywhere besides North America? What is used in Australia? South Africa? The Orient? The Caribbean?

Also, is there currently enough interaction (racingwise) among these various parts of the world to make it necessary or advisable to have the same rating system for cats worldwide?

Would it be easier to compare relative boat performance, as reported from different regions and continents, if we knew they were all using the same rating system?

In the UK we mostly use SCHRS, some races us Texel. When racing against Dingys we use the RYA Portsmouth numbers.

Hi,
Is it a coincidence that you (Wouter) are proposing a measurement system at the same exact time that USSA is proposing a measurement system (IRC)for monohulls to possibly replace the PHRF system?
See: http://www.ussailing.org/offshore/irc/

I have a few comments and questions:
1. You're killing us with verbiage. How about less words and showing some numbers on 10 "popular" boats? Then take these numbers and apply them to several races that have already been completed and published to see what changed and what stayed the same?
2. I personally prefer measurement systems to "Results Based" systems like yardstick and PHRF for both mono's and cats alike, so I am with you on this. However, just as in any science, you don't know what you have until you measure it, so the results must ALWAYS be considered.

Here are three quotes from Einstein that you (we) should consider:

"A man should look for what is, and not for what he thinks should be".

"Any fool can make things bigger, more complex, and more violent. It takes a touch of genius-and a lot of courage-to move in the opposite direction".

And the best for last:
"Not everything that can be counted counts, and not everything that counts can be counted".

3. What info is needed and what type of measurements (if any) has to be done? Will we rely on the manufacturer's data (who always lie on the weight) or will there be a "certified" measurer (as is proposed with the new IRC system)?


Thanks and good luck with your proposed project.

Steven Bellavia
Hobie FX-1, Sail #211

>>How many ratings systems are currently in use by beach cats, and where is each used?

-1- Texel rating : Europe, Asia, caribian althought it is continiously in conflict with ISAF.
-2- ISAF rating (SCHRS) : Europe and caribian. Continiously in conflict with Texel. Its stable base is France
-3- VYC rating (yardstick) : Australia and some asian regions. This is just one of a few systems in Australia but arguably the most dominant
-4- Portsmouth (yardstick ; US version diffes from UK version) : US and UK not much else.
-5- Than a few local systems that are somewhat related to other systems.


>>For instance, is the Texel system used throughout Europe?

No, UK is swinging between ISAF and Texel, France is ISAF and Texel is mainly oriented in North Europe.


>>Is the Portsmouth system used anywhere besides North America?

Yes, IN DIFFERENT FORMS is has sister systems in Australia, UK and some local regions, However these are not compatible with eachother. Often these system use a TEXEL or ISAF system to calculate a yardstick for a new or rare boats because they have no other means to give a relatively good starting point,

>>What is used in Australia? South Africa? The Orient? The Caribbean?

In order : VYC (dominant but one among several), transitioned the ISAF, Texel/ISAF and some surviving local yardsticks, Texel/ISAF.


>>>Also, is there currently enough interaction (racingwise) among these various parts of the world to make it necessary or advisable to have the same rating system for cats worldwide?


The catamarans scene is small enough to make it wise not to waste volunteer efforts in maintaining several different system that appear to produce largely the same ratio's between the various designs. I refer to Sam Evans comparisons of a while back. he showed how little difference there was between the texel system and the Portsmouth system in ratings.

What is the point of making it more difficult to oneself then is necessary ?

Also grouping the world into one systems allows the committee to use alot more data and the quickly investigate new boat where ever they are designed and launched. Right now a new design that has been sailing in Europe for years can still cause troubles in the USA when it jumps the atlantic.

You tell me , what is the advantage of having several if not many different uncompatible systems.

You eventually end up creating conflicts as found in the Caribian regatta's where US I-20's are amazed to be sailing of a different rating. I understand there were other reasons for this conflict but having a single system certainly makes it clear of what your getting into well in advance.

In additions I understand that there are several groups that would like to do nothing more then cocooning themselfs up in their own little OD classes and local catamaran organisations but is this decision made out of emotion or because such a thing is really the smart thing to do ?

I say lets make a impact and solve many issues in one strike. Sure even the new system will have its quirks, however the idea is to have less of them when compared to others and to make it simplier for everybody to use such a system.

I'm not allowed to say this but a measurement rating system does also a good job of keeping track on measurements and builder claims. Arguably a measurer based system can not survive in the US because of the localized cat sailing scene there and the large distances. Why not use the unique situation in Europe where this is possible to benefit the US ?


>>Would it be easier to compare relative boat performance, as reported from different regions and continents, if we knew they were all using the same rating system?


Most definately yes.

One good example, The Taipan 4.9 would immedaitely have had the right rating in 2001. Why because its ratio to the F18's would have been known much sooner because of the race data available.

In principle all rating system work to some extend, there is nothing wrong there. The question is wether we can get an even beter system is we combine the efforts of all committee to the betterment of one system. I think the answer to that is a simple one.

Compare it to this. The metric system to the Imperial system. There is a reason why modern American car use the metric system and standardisation. It is just a shot load easier when interacting with the wider world when everybody speaks the same language. Was the imperial system bad ? No, but there were just more advantages to using the metric system.

Actually the metric system is a construct as well. Key points here were the ease of calculations in a decimal system over a 12 inches in a foot : 3 feet in a yard; 1750 yards in a mile system. The fact that 1kg is closely approximated by a liter of water and the fact that it is scientifically alot easier to define a force and derive a weight from that than to define a weight and derive a force from it (as is the US system).

A similar thing is smart, wise and attractive in the catamaran sailing scene.

Wouter

Steve,

All very good points and I will follow up on them. Please give me a little bit more time as I do really need to lay the ground first. I have a working system so before the weekend I will post it.

I didn't want to post it right away as then some people would look at it, try to found a race result that contradicts it and write if off completely on one (freak ?) result.

I'm killing you with verbiage because the proposed system HAS KNOWN OFFSETS, I'm not arguing that there aren't but just that their magnitude is smaller than in the alternatives and that at a certain level there is not much to gained by going more accurate and more complex.

I also needed to specify where the mods have been applied; to the know problem points

However I'm reaching the end of the ground work and will post a link to a working excel sheet soon. So you all can look.



With regard to US sailing :

There have been informal contact in the past even as far a 2 years ago. I've been at it for a while. I do not know wether one thing caused another. I do understand however that Yardsticks are losing ground as the fleet has become very diverse and getting accurate data to drive yardstick systems has been problematic. Some people are mabe recognizing that when a measurement based system gives acceptable results that then there is no point in putting alot of work in a yardstick system.


Point 3 what is required ?

I answer this in relation to the NMBR system : All of the texel measurement and the measuring of width. You will find that Texel publicizes all of their measurement data and that they have the biggest collection of cat data. This means that not much needs to be done to put the NMBR in effect.

No, we will not rely on manufacturer data. We'll dependent on the system of independent measurements as performed by Texel and or ISAF officials and that of class based verifying committees like the one in F18.



With regard to yachts, a measurement rating system can clean up here as yachts are so determined by a few simple factors. Example : no yacht significantly beats Froude's law. And this is really a harsh limit.

Steven, I will satisfy your requests soon. Pardon me for the extra day or so that it will take

Wouter

>>>Do you actually need to have a focal point in the rule, once the basic numbers have been calculated……?


No, but there are advantages to overlapping the theoretical case with a real case. It makes processing data and experiences easier and it will make the work required on RC's less strenious. Remember how one argument for the F18 was that this allows a large portion of the corrected times to be determined by just copyign the elapsed times ?

If such a opportunity for simplifications exists why not take it ?

>>Boats speed will change as they are developed (F18 will get faster, Dart 18 will stay the same)

As einstein said "everything is relative" ; does it really matter which viewpoint you choose if you are comparing both to eachother ? The only difference if the direction of the change, the amount and speed of it will be same in absolute terms.

Also, the catamaran scene, especially the racing scene, is more and more dominated by boxrule based classes like the F20's, F18;s, A-cats, Tornado's and possibly the F16's and F17's. Is it then wise to choice a stationary class a your viewpoint ? Or do you help yourself by choosing a development class that moves in the same direction and with the same speed as the other classes that dominate the racing scene ?


>>But the rule you propose is measuring theoretical performance, not real world (crew dependant) performance. ‘Driver skill’ is not relevant.


That is true but the foundations on which to base weighting factors and future modifications must come from real life data. Therefor the ability to seperate design performance from crew ability is an important one. This is easy with big competitive classes and not so much so with smaller classes that race mainly OD.


>>Or does your rule propose to give boats that are di8fficult to sail (ie have more sail controls for example) a more favourable handicap ?


No, That is something that will always be difficult to rate. Such a thing will always add much more complexity than can be justified by the gains. Designers must be expected to design boats that have a minimal level of comfortable control. Measurement systems, in basis, rate the potential a given setup has when properly designed. If a design choosed to not implement a downhaul on his boats than this does not impact on the magnitude of its potential even though it will make it harder on the crews to achieve that potential. But then again measurement system allow crews to modify and adjust their boats in non-key points without rating hits. Yardsticks systems however have the added responsibility to check wether a given boat is still compliant with its OD status in every respect. Rating committees, sailing organisations and Race committees have many times expressed that they rather do without such an addition responsibility.

For that reason the approach of a (box rule oriented) measurement system was chosen. It is more flexible and cuts down on responsibilities and work that nobody is waiting for.


>>BUT, I applaud you in trying to come up with a new method. Just don't tie it to one class as the Texel and SCHRS have been once you have a formula.


Well, trying is a to strong a statement. It may seem this way for the coming years but if the F18 classes, for example, choses to drop its minimum weight and increase sailarea than it will move away from the base rating of 100 and decouple itself from the reference number.

It is more like: for the immediate future both things travel along parallel roads, but may well diverge at a later time.

Thank you from participating in this discussion and I appreciate your comments. They are the wet stone on which the system needs to be sharpened

Wouter

Potential simplifications

(not all have been implemented into the working NMBR system excel sheet, sometimes more research is required)


-1-

Replacing rated hull length by hull length overall. Simply measurements and input to the rating formula.


-2-

Replacing aspect related efficiency of sails by a much simpler to use linear regressed fitting. Replacing a expression of 4 higher order terms by an expression in the following shape : rated area = (constant + factor * aspect ratio) * sail area.


-3-

Replacing the higher order rating formula by the much simpler ti use linear regressed fittings. The regression in this case is actually quite good. The higher order Texel rating formula can be approximated within 2 % margin by the linear expression : TR rating = 148.922 -2.750 * rated sailarea -6.141 * rated length + 0.132 * rated weight


-4-

Discard the virtual weights of boats that Texel does. Example Texel specifies the F18 to weight 173 kg = 180 - weight spi gear. Just use the real weight of the platform and raise the spi hit with 1 point. This leads to the same end result as the current texel system because of the largely linear behaviour of Texel (see point 3); The 7 kg deduction Texel uses is equal to deducting 0.132 * 7 = 0.924 of the rating of every boat that has a spinnaker. Boats that are measured without spi gear need to add 5 kg's to their boatweights when fitting a spinnaker. This 5 kg is substantiated by real measurements.


-5-

Discard ISAF spi size impact for a simple fixed hit. By accident the Texel rule has create a situation where all boats of the same length share the same spi area. All spi's can be seperated into three major groups around clear concentration points. These points are 17 sq.mtr. 21 sq. mtr. and 25 sq. mtr. By coincidence a fixed hit seems to be fair to all three groups. At a later stage and after more data research some refinement in assigning the spi hit can be included, but for now the single hit seems to be effective and easy to use. There is however a need to do something with oversized spi like that on the Tornado's, Supercats and Nacra 6.0 NE. It is suggested to hit these with one extra handicap point. If smaller was faster than they would be sailing with a smaller spi so some hit must be assigned. However experience and aerodynamic limits (Theory) suggest the gains to be relatively small so 1 point seems to be enough as well.


Wouter




-4-

No. I don't think a rating system such as this needs a focal point at all once the formula has been stated. All boats just need measuring and weighing and you plug this into a spread sheet and bingo you have a rating.


Your example of F18 reducing weight or increasing sail is exactly what I think any rating system should not be "sold" as tied to a single boat as the focal point. I think it would be good PR to say that the rule / formula was worked out in this way using the F18 performance as at 2004 as the point of referance, but from that point on all ratings are free-floating. Eg, someone puts a Masthead kite on an F18, you can just adjust the rating as such. I put a bigger kite on my 17, my rating changes too.

The F18 becomes 15Kg lighter - I believe entirely possible as the new Nacra F17 is 13.4KG lighter (I have been told) than the Current Inter 17 (Euro version).

Both the Texel and ISAF systems have the very funny setup that putting a spi on a cat-rigged boat only gets 1/3rd the hit than putting a small jib on it. This is not only wrong by a gut feeling ! It is also easily proved that this theoretically wrong. Goes like this; Biggest gains of jib are on reaches and downwinders; only a small gain is experienced on the upwind. When a spi is set the gains of a having a jib on the downwind and shy reaches are nullified by the gains made by adding a spi. So only the small gain of having a jib upwind is left. So this leads to the situation were the spi hit must be bigger than the jib hit when looking at putting either one of these to a cat rigged boat.

This is actually the situation where both texel and ISAF make the largest errors.

Luckily it isn't encountered often

Wouter

Here I provide an implementation of the NMBR system.

I write AN implementation as I've build in a few fine-tune dials. These can be tweaked in order to have the system reflect the reality better.

I've performed an initial tweaking on the data/experience that I had. However it should be regarded as a starting point.

It is not possible to tweak an individual design, I'm strongly opposed to that and think it is direct cause for abuse. All tweaking impacts on all cats. It impacts on some more than others, just like physics would work in real life. This is in my opinion a safeguard against abuse and unfounded tweaking. The way it needs to be done now is that a phenomenon that gives cause to differences must be identified first and by founded by physics. After which it can be implemented or tweaked and all boats get a proportional correction dependent on how much they were affected in reality.

Again I stress this NMBR system is not perfect and I myself can identify some outlying points that look a little of the mark. HOWEVER, I do believe these outliers to be a lot smaller than those that are present in the alternative Texel/ISAF and yardstick ratings.

As of yet I have identified two issues of concern :

The comparison between double handers and singlehanders when a spi is added. I have a feeling that here a phenomenon is at work that limits the performance of singlehanded spinnaker boats that has not be incorporated yet. They all seem to underperform to their ratings. The spi-less singlehanders seem to be alright but the spi singlehanders aren't. One easy solution would be to reduce the spi hit that these boats get and thus make is less than the spi hit on doublehanders. This has however not been implemented yet as I have very little race data that compares the spi equipped and non-spi versions of the same boats. I'm hoping that my current contacts with the US raters can help me here. Anyways, research is continuing here.

The second issue is that to get a ready to go system I've made use of the Texel formula as the working core. I use it less than the orgininal Texel system and that allows me to take out a few defined issues. However there is one issue that I feel is fundamentally wrong with the Texel formula. I truly believe that it makes an error with the M20, M18, A-cat, F18HT and other lightweight boats that are LONG for their displacement. These boats have cut down on wave-making drag in an enormous way but hardly on the wetted surface area. Of course in light winds there is hardly any wave-making drag. Below theoretical hull speed wave-making drag can be pretty much neglected. However Texel still hits longer boats with several points.

There is one experience that I can't tweak into the system as it is. Glenn Ashby has mentioned in the past that he felt that the Taipan 4.9 in the light stuff was very comparable to the modern A-cats. And when looking at low speed drag (wetted surface dominant) such an experience is supported by physics. However it is not by the Texel/ISAF formula's. For the sceptics under us I have confidential data where an World Top-5 Tornado crew on a sloop Taipan raced several races against a World top-5 A-catter on his modern A-cat in the light stuff (around 5 knots). The Taipan crew won all races except 1; there were some 5 races in total. The physical model I derived by other means completely supports such an outcome; Texel and ISAF core rating formula does not. The thing was that wetted surface drag was completely proportional to the other factors and sail drive thus making the drive/drag ratio of both boats very comparable. On this data and others I think texel and ISAF may be off by 3 % in rating the M20, M18, A-cat, F18HT and other lightweight and long boats. (on decreasing order)

Best thing to do would be to regress a new rating formula and replace the formula derived from Texel by that one. I think that would solve the final issue with the NMBR system.

Again, by using the Texel formula the NMBR can never be worse then TExel or ISAF only better as it is corrected for other issues.


What is incorporated in the given version of NMBR ?

-1- Boats get a larger hit by adding a spinnaker.

The 4 point hit was rediculously low especially to the cat-rigged boats. It felt wrong to the sailors as well when looking at the speed gains on the water. The endresults and errors were masked by other "corrections" so the the Texel system did alright in most situations. Mostly by luck and coincidence. One of these was that the jib hit kept on counting when a spi was added making the ratio between sloop spi baots and sloop non-spi boat correct. Of course in relation to cat-rigged boat the whole system went completely beserk.

-2- Sloop rig boat adding a spi gets a reduced jib hit

Simple reason : because that is what happens on the water and in theory. The gains of a jib are lost on the downwind legs when a spi is set and takes over the workings of the jib. We are left with only a smaller gain on the upwind due to having a jib. This phenomenon is now reflected in the rating system

-3- Speeding up or slowing down of boats with increasing winds is incorporated

Simply because this happens. Great example is the US I-20 to a Hobie 16. In the light stuff the difference is alot bigger than a 20 knots. We all know that and we have all seen it. Similar things are reported by Dart 18 sailors when comparing themselfs to H16's. A similar thing is encountered between the I-17 and I-17R as well as between the FX-one and I-17. For this we have abundant anecdotal evidence and race data. Brobu on the virgin Island has commented on this often on this forum

-4- Removing a jib impacts more on a spi-less boat then on a spi boat and in the last case the sloop boat is only a little faster around the cans. (When large reaches are included things may be different. Nut that is distance racing)

Thanks to Tornado Alive I had a good key to tweak the system to. By accident he and his trainings buddies ones races together where one of the boat had to sail without a jib. Because they were trainings buddies we knew how the crew skilled compared. Downwind = No difference, Upwind : in the puff the VMG was comparable. In the lulls the cat-rigged tornado fell slightly back and had to drop a man from the trapeze while the sloop tornado crew could stay out and continue. This suggest that maximum righting ratio (the same in both cases) kept the boats fully powered up tot the same drive as long as the wind was strong enough. When it wasn;t the extra drive of the sloop rig gave the sloop an advantage dispite having to sail a little lower. At the bottom of the excel sheet ( or picture of it) you see this example in rating numbers. By virtue of general rules impacting on all other baots this phenomemon has been extrapolated to all other boats. This solves a big issue that was present in both Texel and ISAF and does closely approximate what a Yardstick will show after several years of gethering data and converging (if ever gethering enough data)


-5- Boards, skegs and asymmetric hulls are all hit differently now

Boards are better then skegs, skegs are better than asymmetric hulls. I've decided against including a formula for boards efficiency in this system like ISAF does for two reasons. I think the formula used is inaccurate. I base this on experiences expressed to me by the Stealth designer. Secondly; it assumes that the hull itself is relatively unimportant. In case of the Stealth we had some good data that said that smaller and low aspected boards only tended to be disadvantaged in the medium wind range. The Stealth design went through 3 different board setup before settling on one setup with the F16 version. The funny thing is that sails tend to show a similar behaviour. Flat in strong winds, fuller in medium winds andback to relatively flat again in the light stuff. It appears boards behave similar. The ISAF formula does some funny stuff by looking only at aspect ratio and not at size. All in all ; I felt that the used formula introduced more errors then it provided increases accuracy. When noting that measuring boards is another thing to do I decided against a complex board rule and keep only adjust Texel where we could do so easily. What we did was keep the boards hit (we can increase or decrease that when necessary) and gave the outdated asymm hulled boats an extra deduction in speed (1 point) when they satisfy the "3 out of 5" rule


-6- 3 out of 5 rule; old boat society

All cats satisfying at least 3 of the following conditions gets a rating one point slower
-1- Cat has assymetrical hulls without boards or skegs
-2- Cat has a mast unsupported by diamond wires or extra shrouds
-3- Cat has a pinhead mainsail
-4- Cat doesn't have a downhaul system nor a mast rotation system that can be continiously adjusted
-5- Cat doesn't have a smooth (rounded) transition from its sides to the deck (deck lips as on H16 and P16)

This ends the abritrary good will points that we included in the Texel system and improves on ISAF that doesn't recognize that these boats are less efficient in design as cat designing has progressed.


-7- Oversized spi hit.

1 point faster if your spi is oversized. Definition according to Texel and ISAF system. It is to much to explain why the Texel spi rule works. It was a lucky guess when it was implemented but it seems to work well. If you do math on it you'll find that it forces the spi's to a constant ratio to the boat size. It keeps drive and drag ratio constant. However we have oversized spis on some boats. We can't forbid them. So we enter the simple rule that 1; no designer will fit an oversized spi when he thinks it is slower. 2; more than enough data suggests that oversized spis are really limited in gains (Nacra NE vs US I-20 anyone ; Tornado vs EU I-20 ?). So 1 points seems to be the minimum (36 sec on hour) and also seems like a good maximum. It sure does simplify things alot. ISAF formula for spis doesn't seem to discriminate much.


-8- Singlehanders are relatively faster in light airs then in heavy stuff

Self explanatory; On of the major bitch points about using Texel and ISAF. Now resolve in a simpler way then Yardsticks do (namely US PN with 5 groups)


-9- Two rating numbers assigned to easily recognisable conditions

Race committees no longer need to bring a windgauge on board and do repeated measurement. Big bitching point of the RC's; at least over here. Now the RC can look out of the boat and estimate how many boats are fully trapezing when going upwind. More than 60 % => high wind rating. Less then 60 % => light wind rating. Sure we can still find border cases where an offset can be found but these are MUCH smaller than Texel and ISAF and Yardsticks groups are either not used often or have insufficent data for all groups to be dependable. Especially when rating new or rare boats. It is also alot simpler to use and each boat gets a correction proportional to how much its suffers. Not perfect but close enough


-10- Some things but it is already late and I'll let you chew on this stuff to begin with


Good luck !

Look in the next post for the excel data sheet , I removed it to make reading the above post easier


Wouter

..

Hi Wouter,

Take your time - it's worth it.

Let me know if I can be of any assistance.

Here's a super simple formula I derived for time-on-time scoring:

TOT Handicap = .0673 x (SA^.584) x (DISPL^-.325) x (L^.624)

where SA = total sail area in square feet
Displ = displacement in pounds
L = length in feet
the ^ means raised to the power

Sorry, no width consideration - but this was just a quickie attempt. (that seems to work rather well, though).

If you invert the TOT handicap and divide by 100, you'll get numbers very close to the USSA D-PN's for most boats (in non-spin config). Try it!

Take care and good luck!

Steve

Wouter,

Quick questions

1, What identifies an over size Spi - is this the same as the Texel definitions ?
2, Would you mind sending me a copy of this to scooby_simon (at sign) ntlworld.com so I can have a play with it later and print it so I can understand it properly. The excel will not print in any way that will be readable from here.

Steven,

This exactly what I mean !

Many sailors think yardsticks like US PN adjust each rating to little quirks in each design, but it is actually not alot more than a large table of numbers that follow a very simple formula.

This is exactly the reason why Texel and US PN give very comparable results despite appearing to be very different. Of course a few exceptions exist.

If we know this then why not make it easier on ourselfs and use this knowlegde to make the system alot simplier and more transparent. Arguably the benefit of a Yardstick is largely a believe that it could be better even though in reality it may not be much different from a measurement system.


Thank you for your support, I need it and it seems others are convinced by it that this is something we cat sailors need to get of the ground. I've been contacted by some already, some even with influence. Hopefully we can get this of the ground.

I will let you know when you can be of assistance. Actually you can already. You can spread the word around in your local area of cat sailors. We need sailor support to convince the power that be that something can be done about many complaints that sailors have of the current setups.

If we all together don't ask and demand such a thing than we will never get it.

Sure they will ry to shoot this done but as our moto says; It may not be perfect, but is may well be better !

So lets go !


Wouter

Speaking of Jibs and Spinnakers.
How about the Hurricane 5.9. They can put on a Spinnaker, use a slightly smaller jib and stay at the same SCHRS Number

But adding a little weight too.

The Hurrricane 5.9 jib was always too big anyway.

Scooby,

-1- Same as Texel definitions (for now) meaning

up to 16 foot => bigger than 17 sq. mtr.
16 to 18 foot => bigger then 21 sq. mtr.
18 to 22 foot => bigger then 24 sq.mtr.

I'm considering two small modifications, but they are something for a later stage. For now this works well enough. To give you an idea. Have different limits for singlehanders. Currently an A-cat can have 21 sq.mtr. and that is a bit much.

-2- I don't mind, everybody and anybody wanting to see the excel sheet can have it as long as they agree that it is my intellectual property !

It is in your inbox, Scoob !

Wouter

A cat with a 21 kite would be (very) silly

Got the sheet

Thanks....

Quickly spotted one slight error, the weigh od the Inter 17 is 161 with the Spi rigged (and it makes a difference of one point on rating)

Also, I dont really think an Inter 17R(spi) is quicker than an F18 in light and the same in heavy.

But it is a start

Good work

How did my Hobie 20 post jump to Wouter's "Mouse Trap" thread It is listed in both

I'm think that may actually be acurate...or close to it. The I17R carries less crew weight and points higher.

But also less righting moment and less pairs of hands

Which rating sys will bring the SC20 rating down to a realistic level? That's the one I'm for.
JC

-1- I used the Texel core so all weights are excluding the spi gear, take a look at the F18, F20, F16 weights as well It is something I want to take out of the system as well as stated in the "Potential other mods" post, but I haven't done it yet. You can pretty much 1 point to all spi boat ratings if you use the weights including spi gear and then subtract 1 point because I will lower the spi hit to compensate. End result ? Zilch. That is one reason why I haven't implemented it yet. I'm waiting on some feedback from others.

-2- I-17R, this is an identified problem point, see the post publicizing the numbers. I'm hoping that US data and Mark Schneider can help me here. I don't have good I-17R with spi data. There is one thing to say for the NMBR rating for the I17R. This boat has almost the same mainsail and mast as the F18's on a lighter platform with less crewweight and a considerable spi. If the fundamental Texel formula is right (Not entirely sure here see post) than the I-17R should be faster in light air ! However I think NMBR makes it too much faster. I feel the cause for this is found in the Texel rating formula itself. Hence my suggestion to do a new regression on the data. In summary; we are working on it.

Also please correct the wrong width for the I-17R ; the sheet says 2.60 mtr. but it should be 2.50 mtr I believe.

>But it is a start,

I would say look at the other things, these seem to work pretty well. Of course it is a bit much to ask to get it right the first time. Some tweaking is required.

Wouter

I(F)17R should be 2.5 wide (same as I17)

F17 press release

Hey Jake,

You can help me here. (either via the forum or in private)

I don't have much data on these singlehanders and I'll need that in order to tweak the single handers. You as a F18 sailors may help us out here.

How often have you sailed against these singlehanders and how did they compare to your F18 ?

I'm particulary interested in the I-17R as that is such a clear example and I can cross reference it with I-17 data. These are great setups; Identical setups with only a small of differences. Makes for great tweak keys.

Wouter

How about a NMB rating for the SC20 TR with spi of

Light weather 88
heavy weather 92

SC20 TR no spi :

light 91
heavy 96

Compare to US I-20

Light 92
heavy 95


Seems a whole lot better doesn't it ?


I used the following specs (please give me the correct one if they are wrong)

weight 200 kg (441 lbs)
length 6.10 mtr (20 foot)
width 3 mtr (10 foot)
Mast 11.5 mtr (38 feet)
Mainsail 22 sq. mtr. (236 sq. ft.)
Jib 6 sq. mtr. (65 sq. ft.)

And I only needed 60 seconds to acquire a rating and that included looking up estimates of the specs via internet


Is that satisfactory ?


Wouter

>>But also less righting moment and less pairs of hands


Wait a minute. You can't use the righting moment excusse here ! In light winds (NO TRAPEZING group) righting moment is not an issue as all crews can then generate more rigting moment then they need.

And in the strong wind rating the righting moment was calculated and used to compensate the rating. The I-17R received a swing of 6 rating points (3 minutes and 36 seconds) while the F18 good a swing of nothing ! By this the I-17R is rated slower than the F18 in the heavy weather rating (trapezing group)

You may think the swing is still not enough but you can't say that NMBR doesn't take "less righting moment" into account because it does.

>> less pair of hands.

Well yes, that is another matter although in the light stuff this may not be much more of a factor than 1 or 2 rating points. I mean how much longer do you need as a singlehander to set or take down a kite in race. A few second. Will 36 to 72 second compensation be good enough for that ?

By any account this is only a small offset.

In strong winds I say "less pair of hands" is a bigger factor.

Again guys please look at the other things as well. The single hander with spi was already identified as an point of attention in the post giving the NMBR table. The spi hit to singlehanders seems to be a bit harsh, I'm contemplating what to do with it already.

What do you guys think of the H16's versus F18 for example or the evert recurring Curacau US I-20 to EU I-20 issue ?

Wouter

Hey Wout,

The SC20 is 12' wide, but i'm not sure about the wt and sa. What does the change in beam do to the #?

Here is the rating correction for the 12 foot wide SC20 over the earlier presented 10 feet wide numbers


New specs

weight 200 kg (441 lbs)
length 6.10 mtr (20 foot)
width 3.66 mtr (12 foot) (This is some mightly wide boat)
Mast 11.5 mtr (38 feet)
Mainsail 22 sq. mtr. (236 sq. ft.) luff being 11 mtr
Jib 6 sq. mtr. (65 sq. ft.) luff being 5.5 mtr.
+ spi


New ratings SC20 at 3.66 mtr width

Light weather 88
heavy weather 89

Compare this to :

SC20 at 3.05 mtr width

Light weather 88
heavy weather 92

And the US I-20

Light 92
heavy 95

If we take the spi off the SC20 than :

Light 91
heavy 93

I think this reflects the (scarce) real life data well. At least heaps better then PN of 64.1 vs that of 59.2 to the US I-20

Notice how the new width didn't change any off the light weather ratings (No trapezing group); only the strong wind ratings (Trapezing group).

Again we needed only a few seconds to get the new numbers.

Also interesting is to compare the "sc20 at 12 feet width" numbers tot the ones of the M20

M20

Light 86
heavy 90

So the M20 is expected to be 2 points faster in the light stuff and a fraction slower (1 point) in the heavy stuff.
The M20 has a 4 point rating swing from light to strong and the SC20 only 1 point. This all due to the ratio between rig and width. The Hobie 16 (L = 116 ; H = 114) of course has a opposite swing (getting faster) of 2 points. So the difference between the M20 and the H16 reduces from 30 points to 24 points when the wind conditions transitions from no trapezing conditions (light winds) to Trapezing conditions (heavy winds). The difference between the SC20 and the H16 only swings from 28 points to 25 points. To go one further US I-20 (L92-H95) vs H16 : difference goes from 24 points to 19 points. However the difference between the H16 and a nacra 5.0 remains about the same (0 point differnce to 1 point difference). Both of these speed up equally due to changing wind conditions.

Isn't this reflecting what we see on the race course ?

Wouter

Hi Wouter

I have been rescoring our buoy's regattas with the new rating scheme and the results look pretty good in that the elapsed time differences needed to win are pretty close for what I would argue are sailors of equivalent ability.

I had to guess at numbers for the Hobie 20 and the Shark is there any data in texel that can be used to compute a pair of ratings.
Mark

Thanks alot Mark for your first report on running the numbers on your race data.

It makes me feel very good that the initial test shows some encouraging performance.

I'm looking forward to the report after you have run it all. You know some tweaking can still be done.

You what's funny, there are some points I think to be remarkable but it may well be that my own prejudice is unwilling to believe what the formula's are saying. So again, I'm looking forward to your commment and or report after you've run the data on it.


Texel data :

http://www.texelrating.knwv.nl/


Hobie 20 :

Best look up the Miracle 6.0 in the Texel rating and use that data. It is my believe that this boat is the same as the US Hobie 20 Miracle. One point of note though, Hobie NEVER officially imported the H20 Miracle to Europe. So these are "privately" imported boats and may have undergo some modifications with respect to the US versions. Never the less it is a good place to start.


Shark :

There is a shark catamaran in the listing but I'm sure wether that is the same Shark that you use in the USA. ONly way to know for sure is to contact the Shark class association and ask them about the specs.

I can tell you however that IF the Texel listing doesn't have the numbers on a boat that NO other rating system has them. Not ISAF and certainly not the Yardsticks. The Texel listing is by far the most extensive data base on catamarans around.

If a boat is still not named in the listing that the following rule of thumb works pretty well.

Length : Take the length overal or waterline length. The rating is not very dependent on which one you use.
weight : Often this is easy to guess. 14 ft = often about 100 kg, 16 ft = often about 135 kg, 18 ft = about 160 kg 20 ft = about 190 kg
Sail area = Take an F18 sailarea and scale this area in height to the mast area and in width to the hull length.
Luff length main = mastlength - 0.5 mtr. (a very good estimate)
Luff jib = nearly always between 4.25 and 5.5 mtrs. depending on the overal size of the boat. A rought guess will do here


Wouter

mark,

This is what I found after some 60 seconds on the internet and thanks to a post by Same Evans.

http://www.sharkcatamaranclass.org./WHAT.HTML

Shark specs

Length 20 ft (= 6.10 mtr)
Width 10 ft ( = 3.05 mtr)
Weight 450 lbs (= 204 kg)
Mast Height 28.5'= 8.69 mtr => give mainsail luff estimate of 8.19 mtr.
Sailarea total 275 sq ft. = 25.6 sq. mtr. => lets divide that into 18.6 sq.mtr. main and 7 sq.mtr jib
Jib luff should be about 5 mtr with a mastlength and boat width like this.
daggerBoards
No spi

These estimates (and facts) give the shark a provisional rating (we had to guess at some specs) off

Light 99
Heavy 98


I ran the numbers on the Hobei 20 as well (the number that I know or estimate)

specs

Length waterline = 5.82 mtr.
width = 2.5 mtr (?)
weight = 201 kg
main = 17.97 sq. mtr. by 8.81 mtr luff
jib - 6.34 sq. mtr. by 5.74 mtr
Boards
No spi


NMBR ratings

light 100
heavy 102

Mark I send you an excelsheet so you can punch in the numbers of some other boats you need yourself

Wouter

I appears that the Texel rating listed Shark is about the same boat. Only texel lists a shorter mast and less overall sailarea.

On these texel specs the shark get the following NMBR numbers

light 101
heavy 99

If we have to guess at it a number around 99 seems to be right. Only this design is pretty old and arguable less efficient. I'm not to sure wether the NMBR rating gives a very accurate prediction here. Afterall NMBR estimates potential for a given box of specs. It is up to the skills of the designer to bring out that potential in real life. ONE-Design classes of 40 years are arguably at a disadvantage here. They can grow with the new developments.

But I anxious to hear how these numbers come out of your tests

Wouter

The Shark was originally designed to fit into the IYRU B-Class specifications, with 235 square feet of sail. But the Sharks that were exported to the United States (and those that were subsequently built in North America) had the higher sail area of 275 square feet because the United States, in general, has lighter wind conditions than Europe.

So any Sharks sailing in Europe may have the original sail area of 235 square feet. (I don't recall ever hearing anything about a difference in mast height between the Sharks in Europe and those in the U.S.)

Plus, the Shark has centerboards, rather than daggerboards, and the maximum depth is 3'6".

NMBR is easily adjusted to produce distance racing handicaps.

The idea behind it is quite simple and yet simply copying the same approach to Texel / ISAF and Yadstick systems will not result in the same accuracy.

Here an explanation of how it works

Pretty much we can devide any race over three main courses.

-1- Pure upwind sailing (as high as one can)
-2- Pure down wind sailing (as low as one can)
-3- And the widened area of reaching (anything between the regions of -1- and -2-)

-1- is most impacted by righting moment and pointing ability.
-3- is most impacted by having a spinaker or a jib
-2- is mostly impacted by good hull design and efficiency of the traditional sailarea (only main and jib)

Right at this moment both the spi hit and the righting moment correction are implemented as follows. (I only give part of the equation, only the working core.

(0.5 * spi hit + 0.5 * righting moment corr) / 1

The 0.5 is actually a course distribution factor. We have currently taken 0.5 as most data I have right now suggest that a non-spi boat takes about roughly 50% of the time to go upwind. Some tweaking can be done here.

By changing this course ratio to say 100 % upwind and 0 % downwind we can produce custom handicap numbers for races like the Tybee 500 and steeple chase. Of course any ratio between 0 % upwind work and 100 % upwind work is possible. By changing these ratio's one can see that the impact of both the spi hit and limited righting moment hit are forced to influence the ratings proportionally to the sailed course.

Smart people will notice how the reaching leg in not implemented yet but by adjusting this formula too :

(Downwind portion * spi hit + (1 - downwind portion - upwind portion) + upwind portion * righting moment corr) / 1

and use 2 percentages to defined the course. Portion upwind and portion downwind. The reaching portion is then the remainder.

This way we can modify the framework by including the reaching legs. On these legs no spi hit or righting moment corrections are taken and so the pure speed potential under traditional sails (main and jib) is taken and assumed to be fully powered up all the way over the conditions.

The framework is simple to implement and by adjusting just two input variables the excel sheet will produce ALL the new custom handicaps for a distance race within a blink of an eye.

It can be proven theoretically that the accuracy of the rating is somewhat less than those for a well layed out bouy race (for which the rating were optimized) HOWEVER, the same proof shows that the NMBR custom rating will be noticeably more accurate than all other systems in use today. Simply because it DOES compensate for the different course shape of the distance race AND because it does so in a way that is SIMILAR to what happens in real life. To how real life physical processes determine the performances under the different distance racing conditions. Ex. We all understand how sailing 90 % of the time upwind and 10 % of the time downwind under spinnaker proportionally impacts on the benefit of having a spi. The shown framework does compensate in exactly the same way.


The same framework can not easily be copied and used with Yardstick systems as in Yardstick systems the distribution between upwind, downwind and reaching performance is simply not known. One needs this in order to have them impact on changing course distributions.

Texel nor ISAF can easily use this setup untill they change the way that they implement the spi hit. By this I mean that they can't use it untill they have decoupled the spinnaker and jib related performance on the downwind legs. This is pretty fundamental stuff and many important people unquestionably want to discuss such a thing at great length.

So distance race organisers !

There is also a better mouse trap for you guys.


Wouter

The plan to get the NMBR system accepted.

The first conclusions by some reviewers (independent from my person) are that the NMBR system, in its current stage, appears to produce more balanced scores and put crews of assumed equal ability closer to together. One comment was that it actually looks pretty good. I'm quite contend with that.

But this puts us to the next level.

There are two things that need to be done :

-1- additional testing on real life race results and possible tweak the system a little here and there for extra accuracy

-2- Start up a program to contact all the rating committees and get the system accepted.


Point 1 and point 2 can be executed simultaniously as more and more signs are coming in that NMBR is producing better results than its alternatives. So additional accuracy is welcomed but not necessary. Also the largest gains of NMBR are to be found in its ease of use. It involves much less work than a yardstick system. For the ISAF/Texel corner the NMBR system solves a few claring issues and produces much more realistic results for the same effort in maintaining it as the ISAF/Texel systems currently in used. Also it is more flexible as it can produce custom ratings for one-way handicapped races etc.

Right now, I'm working out a plan to tweak the system further; I'm in contact with a US party for that.

With regard to acceptance I propose to go about it in the following way.

-1- Consolidate contacts with the USPN committee. Right now they are the party to most benefit from it and it will allow them to offer a remedy to RC considering breaking away from USPN in favour of Texel like rumour has that Tybee 500 is considering. In short the time appears to be right to expose the USPN to an alternative.

-2- Next step will be to contact ISAF as I know they are looking to improof on their system for several years now. Not much is happening so I think they are at a dead lock. The medicine might well be to expose them to a fully operational system that US parties have tested for improved accuracy. Simply put we can use the US to break open the possible deadlock inside the ISAF committee. Afterall, ISAF would like to see a single system around the world and the US is very much an sizeable and important block in that. Also this is the most effective way for US sailors to influence ISAF into a system with wind dependent handicaps etc. In short to make them accept some of your wishes/demands. Of course ISAF is looking to stuff Texel as the more dominant system. So the US is the juicy bone and having a noticeably better system is the rewards for ALL OF US.

-3- Of course if USPN and ISAF go like domino's than we can really put some pressure on the Texel system and most likely get them to accept to NMBR system in it total without counter demands. I think I have the inroads to that already. I hope my former collegues at the Texel system will forgive me for this but the current make-up of the committee is in need of a make-over and nearly all parties cooperating with the Texel committee adhere to that view. So in short is the old committee holds out despite convincing arguments then I will contact the parties using the system directly and pry them of Texel that way. It will be their call to decide to co-opt or be made disfunct.

-4- Yardstick systems in general. Well Yarstick in the UK is already losing to ISAF at this moment. The transition is slow because of the large and known issues in ISAF. With NMBR these are as good as solved and so further resistance will be solely based on emotion and not on verifiable concerns. Asia, africa, and south america are largely to small to maintain their own independent yardstick systems. Alot of them already use ISAF or TEXEL because that is much easier for them, when the US and the EU are on the same line regarding a handicap system then surely they will all transition to that system over time as well.

-5- Australia and New Zealand. This will be tricky as these scenes tend to be very independedly minded. However right now several yardstick systems are still competing with eachother also the dominant VYC suffers from all the issues linked to yardstick systems and uses on 1 rating number for all conditions. Arguably for them a large improvement can be gained by using NMBR. The largest of all. It will probably take some massaging but also when US and EU are in agreement than such a thing must go a long way in presuading the Aussies.


As you can see ; USPN and it committee play an important role in all this. They are the first step and those are always very important. However I do plan to be in contact with several parties simultaniously.

I'm expecting a list of demands from several parties (or should I say whigs) however I will not accept any demand that are different from a general wishes regarding the use, shape or accuracy of the NMBR system.

Simple reason being that I see no point in sacrificing ease of use and accuracy simply because a whig wants to boast that he influences the development of the NMBR system.

I will give an example ; a party can demand that a rating should be adjusted when a carbon mast is used. I for one do not claim to know how strongly and in what way a carbon mast affects performance. Nor do I know of a easy and simply way to implement a fair correction. In addition I can't even proof that having a carbon mast impacts on a boats performance in such a significant way that it requires a handicap rating correction. To give an example ; the case for hitting wingmastswith prebend and spreaders when compared to a spreaderless teardrop shape mastsis ALOT stronger and yet NO-ONE ever felt the need to hit wingmast individually. I found that the mere mentioning of carbon makes alot of sailor skittish. This is an emotional response and in many cases it is not well founded in physical phenomena or even real life.

I do very much expect from the official that they make a profound effort to understand why certain things (factors) were included and others were not.

In general I compare this to the following example.

Double glassing.

Going from single glassing to double glassing for windows gives a 50 % reduction in loss of warmth and thus leads to fuel efficiency in the home and savings despite the extra expense linked to double glassing. We can repeat the trick of course a good for triple glassing or event quadriple glassing. The gains will be additional 17 % and 8 % respectively when going from one to another. Theoretically speaking additional gains are made however in reality triple and quadriple glassing doesn't make economical sense, the costs of these outweight the potential gains. It is therefor foolish to seek such windows.

Measurement ratings systems are much the same. After a certain minimal number of inputs the potential gains of adding another input will become very limited and more often then not the additional costs of such an addition will outweigth the potential gains. Carbon mast hits were just such and example and actually ISAF has done away with those in 2003.

Wouter

Wouter,
When calculating downwind sailing, you say "as low as you can go." That means straight downwind. Is that what you mean?

Also is this the correct order of these three items? Well, I mean are the items in the right order but are the numbers on the wrong ones?

-1- is most impacted by righting moment and pointing ability.
-3- is most impacted by having a spinaker or a jib
-2- is mostly impacted by good hull design and efficiency of sailarea

No, I would assume that he means best VMG downwind

Mary,



It is actually a less accurate way of describing a situation where a crew tries to sail as deeply as possible without taking a negative hit in downwind VMG. I use this shorted yet less accurate phrase to keep the test readable.

May I should write "With the best downwind VMG as they can"




Actually the numbers do correspond with the numbering of the preceding listing. I chose to exchange the -3- and -2- lines to first comment on upwind and downwind as these are more important and are currently implemented in NMBR. The reaching part CAN be implemented easily but isn't as of yet. However I'm planning to do that this weekend as it is an action of a few minutes and it doesn't impact in any way on the currently reviewed ratings. It will be an adaptation in the underlying framework that will stay dormant untill used when producing distance race handicaps for a given race. But even without this particular modification the NMBR can be use to produce more accurate distance race handicaps then the other rating systems. It's just that it is so easy to get some extra accuracy out of it.


Wouter

Okay, now I am really confused. Here are the descriptions of the divisions of the course, as you gave them:

"Pretty much we can devide any race over three main courses.

-1- Pure upwind sailing (as high as one can)
-2- Pure down wind sailing (as low as one can)
-3- And the widened area of reaching (anything between the regions of -1- and -2-)

-1- is most impacted by righting moment and pointing ability.
-3- is most impacted by having a spinaker or a jib
-2- is mostly impacted by good hull design and efficiency of the traditional sailarea (only main and jib)"

So why do you first have 1, 2, 3 and then have 1, 3, 2? In the second case it looks like the 3 should be 2 and the 2 should be 3. In other words, the digits are transposed.

Ehhh, I think you are correct, Sorry

I've reread my post and indeed I think you are correct.

I switched over the numbers but the not the phrases following the numbers (as was intended).

So, yes the bottom listing should read :

-1- is most impacted by righting moment and pointing ability.
-2- is most impacted by having a spinaker or a jib
-3- is mostly impacted by good hull design and efficiency of the traditional sailarea (only main and jib)"

Thanks for spotting that one Mary !

Wouter

I forget the best part for distance racers. Well forgot to mention it as it is implemented in NMBR.

And that is that no RC will ever have to face the problem of a crew entlisting themselfs without a spinnaker in the last possible moment when it has become clear that the distance race is going to be an all upwind beat while the others are required to carry their spi hit.

The NMBR system, after punching in the course parameters, impacts the spi hit only on the portion of downwind work in the race. If there is none then there is no spi hit for the spi boats as well. So when using NMBR in this setup every crew can entlist in any way they like and luck of having favoured conditions will not lead to unfair ratings.

It is difficult to sum up all advantages of NMBR in a clear overview as there are a considerable number of them. Best way to look at it is like this. NMBR is mildly more accurate than its alternatives and noticeably more accurate when looking at rear boat or boats with extreme ratios like the A-cat. HOWEVER the biggest advantages are found along the lines of ;

-1- avoiding pre-race hassle with crews jockying for a favourable rating by milking the known problem points
-2- general ease of use and ease of creating more fair rating numbers for distance races.
-3- transparancy of the system; leading to a higher acceptance of the system by the sailors

when the system becomes official its (internal) workings will be fully documented online and available to all. NO SECRECY, NO MAGICAL PROCEDURES leading to remarkable new ratings.

-4- Much improved rating handling and ease of chosing the right group and calculating corrected times by the RC.
-5- Much less work required to maintain the system.


Wouter

Couldn't wait ; So this distance stuff has been implemented.

Actually it had a few positive side-effects.

It took out an correlation between the spi hit and the heeling/righting (overpowered) compensation. The effect of this in the old system was neglectable but still it is nice to have made them fully independent.

Another side effect is that the spi hit is now defined in the ACTUAL speeding up that a boat experiences on a downwind leg when adding a spi. This solves the "how can a spi boat only get such a small hit" issue for ever. The current hit is that a cat is 25 % faster under spi than the same boat without a spi on the same downwind leg. The expected tweaking in the near future may adjust this hit a little bit but this sure feels more real than 4 % already, doesn't it ?

So distance racing guys. The things you want to see in a handicap system are now available as well. No more "100 % upwind sailing with a spi hit while the other ..." blues anymore. If the race is all upwind with tacking than the spi hit is not excersized. Only thing the race organisers need to do is type in "100%" in the input field called (ratio upwind work) and all ratings are compensated. Spi hit is gone and heeling/righting compensation is taken over 100 % upwind work.

With regard to these (one-way) distance races I dare state while standing on solid ground that NO other rating system even approaches the accuracy of the NMBR system.

Note : All ratio's imaginable for "portion upwind", "portion downwind", "portion reaching" can be entered as long as the three added up result in 100 %. This means that all and any race course shape can be accurately rated under NMBR by having it produce custom numbers for your race.

I'm actually quite pleased with this version 7 of the NMBR-system myself.

Expanding the system took only 60 minutes and that was because I couldn't find a typo that stuffed things up. It convinced myself of how good the basic framework really is. It is definately the most flexible system available, by far.
And it does exactly what you expect it to do. Even more so, the framework is not even that high tech. One could explain its internals to a novice on the back of a local diner napkin.

Now lets see if we can get this NMBR show on the water !

Regards,

Wouter

Firstly the ratings for a typical windward-leeward bouy race :





Secondly the CUSTOM ratings for a specific one-way distance race on a given day (Steeplechase, Tybee 500, etc)




If you don't spot the changes right away then look at the following boats

F18 (stays at rating 100 by design, it is used a pivot point)
Hobie16 (has to sail seriously faster, when compared to pivot F18, due to having a reaching leg and hardly having any spi leg for the F18 to stretch its legs)
A-cat (has to sail alot faster, relative to the pivot F18, because their is so much upwind work for it to excel in)

These are 3 extremes, All boats are affect proportionally. The reason that the F18, F20, Tornado, M20 and SC20 don't change rating is because these are simply impacted by negative factors as much as the positive factors. For example the M20 gains on the upwind but looses alot but not having much spi sailing as well. These two apparent compensate eachother largely and its rating only drops on point in the heavy air.

Think really hard before you reply to these numbers, some numbers may sound weird at first but really, they all make sense when you analyse what is REALLY going on.

Of course the CUSTOM ratings converge back to their standard values when the distance race course input approaches that of a typical bouy race as we all expect would happen.

I will admit to the Shark rating being a little bit harsh but then again that boat is so outdated in its design. It has the same general dimensions as the H20 but still can't seem to speed up till within 12 % of the H20 speed under USPN. And it only just reaches 86 % of it potential speed as predicted in its handicap. That is what old technology does to performance of a catamaran ! This problem point has been identified and we are discussing how to adress it.

Have fun, comparing boats and numbers.

Wouter

.

Wouter,

As many times as you have insulted America, Americans and the USAF over the past several years,
how can you expect us to drop our system and help you convince the Texel and ISAF to adopt your little "brain fart" system?
WHY DOES THE USAF HAVE TO BE "the first step"?
Did ANY American ask you to invent a new system?
WHY DO YOU NEED AMERICANS?

YOU live in Europe, where the ISAF is based.
YOU live in Holland, where the Texel system is based.
YOU claim to have close personal contacts with the various European organizations.

Let us see if you can con your own countrymen first.

I see that you have set yourself up as the final arbiter of any and all changes that anyone may suggest.
Of course that is because you know more than anybody else.

If anyone adopts the "BF SYSTEM", will you immediately relinquish all rights and authority over it to the organization adopting it?

(note to reader, after the first few compulsery insulting remarks to Sam I will seriously adress his "points")


Because, well, such an acceptance would piss you off and that in itself would be enough reward for me. Do you feel more important now ? I appologize for totally forgetting about you Sam, but then again you have been so quiet lately.

And as a serious response to your questions.



I know I have insulted you many many times and have nothing but total disregard for you but don't kid yourself that that is because you are an American. You completely earned that honour by your having your own special kind of charming character. Of course, I divert as the main question is :"what has all this to do with rating catamaran more accurately ?"





Simple. because one has to start somewhere one choose the area that is most susceptable to chance and arguably USPN is more open for that at this particular time. Simply put, there are rumour of US events adopting Texel or ISAF and US sailing is open to new idea's while NO event in Europe and NO rating organisation in Europe is seriously considering bringin a Yardstick system back. For exately the reason why US sailing may want to consider chancing systems. Less work involved in maintaining the system, no more swinging ratings, no more convergence time for new designs and related upheaval, no more massaging of rating numbers by carefully calculating crews. Simply Put US sailing is sensitive to that while the area's already using a measurement system are not. US sailing is also the area to gain most by using NMBR, BY FAR ! Furthermore I don't need or request their help in convincing ISAF or Texel, a choice by them to use NMBR would be all I need.

ISAF on the other hand is known to reconsider their current system and so we WILL work them over simultaniously as USPN. In addition ISAF will most likely be very attracted by a juicy bone that expantion to the US sailing scene presents.

Texel (my own old system) will get a more harsh treatment therefor so much for favouring what is closest linked to myself.





What does the US Air Force have to do with it ?

If you are talking about USPN then all I can say is "a step has to be the first, Some consider this to be chosen for that as a honour others rather be the last step. So on what ground do we choose to take either way ? "

Besides aren't you happy that finally somebody is making the effort to adres all the complaints and misgivings in a rating system ? You are likely the guy that complaints about a desease all his life and than scolds the party producing its cure for only doing it for the money.

Who gives a damn ! End result is that a cure is available and ready to be used. THAT in itself should be all the convincing you'll need.





Should I have been asked by an American ?
Would that have made a significant difference ?
Is cure designed by an American always fundamentally better ?
What if I say that a group of Americans DID ask my to design it and that you were one of these ?
Remember the Carl Roberts discussions (including me) about PN and measurements systems a few years back, and how you liked to shut him (us) up by challenging that if we thought something better was possible that we should then proof it by designing such system and have it working ?
Would you have asked wether an American party asked for this system if it was designed by an American ?

Answer all those questions for me first please.





Who said I needed them ? I want them to be included because I value what they can bring into the system. What I do need are volunteers who are capable of regarding themselfs as cat sailors working to implement a better system over being Americans first. Obviously considerations of nationality or even ethnicity are far far removed from any action or intend linked to the NMBR system. Such considerations would amount pure and simple to bigotry and be far removed from any useful interest in producing a better system.





First I'm not conning anybody. I have layed bear the internal workings of the system to various parts of its implementation and have produced is numbers for all to see and test. I also supplied working excel sheets to various (US) parties who have shown interest in testing the system on their race data. Till now the result are considered to be very good.

Secondly, I did try to convince my own country men (sound so much like a term a bigot would use) of the system. Actually I had a system ready in 2003 and had in its entirety proposed it to the Texel committee. The two persons currently in the committee as everybody, else had resigned over various disagreement matters, looked at it - found it all very interesting - and did absolutely nothing with it. Well, they suggested that Texel would be expanded with a reefing compensation for high winds, as if Beach cats reef their sails when it blows past 12 knots. You have to understand that the current Texel system is run by the original inventor (former accountant) who is, I believe, now 84 years old and a volunteer who knows alot about sailing but very little about the underlying physical principles and scientific studies as were preformed over the years at universities etc. The other, more experienced, members resigned in the past because of getting tiring of banging their heads against the wall. I admit that my decision to resign factored this in.

So in a way the USPN approach it already the SECOND step. I guess you will now cry foul that I didn't make the USPN the first step in this multi year project. Anything to stake poor old Wouter , right ? And the rest of the catsailing community by killing off a better system (as confirmed by AMERICAN parties testing it on actual race data). All because off personal satisfaction.





Call me arrogant but regarding matters relating to NMBR, I MOST DEFINATELY AM the guy who knows more than anybody else. Worked with it for years now and intimately known all its finer details and why certain carefully chosen balances contribute to its superrior accuracy.

Who else is better qualified to act as a final arbiter ?





Why would I hand over all the control to a local organisation like US sailing, Austrlian Yachting Association, Dutch Surf sports Federation, French Association of sailing , etc, etc.

Mostly likely several local organisations would feriously object to any local organisation fully controlling a system that impacts on all associated area's around the world.

If anything the control and rights should be handed over to an seperated international body like ISAF or to a newly created organisation that would enclosed committee members of all associated area's.

You surely weren't proposing I would hand NMBR in its entirety to US sailing were you. That would be like handing it over the French if we were to reverse the perspective. I'm not that dumb. Such a thing would seriously impede NMBR's growth and acceptance and we would end up with endless Nationalistic inspired quarrels that would benefit no-one.

So Sam are you part of the solution or part of the problem ?


Wouter

Well the soporific effects of excessive turkey does it again. We enjoyed a very fine deep fried turkey, and I thought I'd contribute our injection recipe to the debate on catamaran hanidicap rating systems.

The original recipe came from a fellow called Earl Richard - who lives in Baton Rouge.

2-3 cups White Wine
1.5 oz margerine
1 table spoon onion powder
1 table spoon garlic powder
1 table spoon black pepper (finely ground)
1 small bottle of tabasco sauce (59 ml)
1 table spoon Zatarans liquid crab & crawfish boil

Warm the white wine and add all the ingredients and whisk. Inject into the turkey (about 13 lb bird is ideal) and allow to marinade over night.

Then rub with Tony Sachre's seasoning and commit to the peanut oil (pre heated to aound 350F). Fry for 3.5 mins/lb. Delicious!

And much more rewarding than listening to you two trading insults.

Chris.

The NMBR website is up :

Yes, between all those posts I typed over the last days I also found time to make up a bare but working website.

http://www.xs4all.nl/~whijink/NMBR/

Over time this site will be improved and the info enclosed will be expanded.

Writing good content takes time y'all

But something needed to go up now, so that we can accomodate the growing interest and there is good news. But more of that in the next post

Wouter

Good news, NMBR is influencing and having effect.

I running down the list of all larger rating systems and contacting their respresentatives and one system has expressed being influenced by the techniques developping in the NMBR project and is currently implementing various parts.

Another system has ran some of their own actual race data through the system and found it to perform quite well, if not to say very well.

Now, this thing is growing over my head in a serious way.

So I will plead for help of you guys, the same that have expressed how things should or could be better in the past. But may be even more of all the people I roughed up in the past, because some of these have access to boats and data that are very attractive to us. But I ask also the help of the sailors that normally let everything blow over.

This is our single, biggest and best chance at significantly improving handicapped racing for the next 10 to 15 years.

I'm not saying this lightly, this is really true. I know what I had to do over the last 4 years to get to this system and to get it going and believe me this sure ain't happening again soon.

So who is with me ?

Bill Roberts ; I want to rate your boats accurately above all else but I need really good measured data on that. Can you help me here.

W.F. Oliver and the javelin 2 guys (F18HT's sailors also welcome) ; same there, we want to rate you accurately above all else and found that you guys represent a very valuable optimizing key to us. Wanna help getting your own boats rated accurately on either side of the atlantic ?

Inter 17 sailor : Same for you; you guys also represent a very promising optimizing key for NMBR. I only need your race data and the willingness to take along a GPS for one afternoon and blast around somewhat.

Hobie 20 sailors : Mark Schneider found your ratings to be suspect while all others were really good. This can only be caused by errors in the input data. Any of you want to help us get the right specs for the US Hobie 20 (a boat that never made it to the EU except in a few cases where the boat was modified)

US I-20 sailors : we want to finally get a properly measured area for the US I-20. can you help us ? Think of the benefits you guys will get when sailing at the Caribian regatta's. I can't elaborate but I can likely make it worth while for you guys even on the very short term.


With your help and some GPS tracks and measurements I can boost accuracy of NMBR well beyond Texel, ISAF and ANY yardstick system ever deviced. I'm not playing big here, I REALLY mean it.


One more thing,

I'm willing to set the example and pull the car for ONE YEAR. After that you guys will be on your own and can wait for ohhh, a year of 15 for another fool to come along and do all that I have done on improving ratings. Goz, I sure ain't gonna do this again.

So we all better shape up and get this thing flying. We will all get a better open class racing scene in return.

To the sceptics, how will you feel when in a years time it will turn out how unique this time frame really was and it was all lost do to some sceptism ? Then you will have both been wrong and the reason why a better way didn't make it.

All the guys who have mailed me in the past weeks, thank you for your support and I fear I will mail you all back the coming week and ask for some of your time and effort to help this project.

The best to you all and lets show the world what we can do.


Wouter

I like tis one
scratch teriyaki sauce

teriyaki

4 lbs. sugar 2 lbs. 1.33 lbs. 1.00 lbs.
3 lbs. ginger root 1.5 lbs. 1.00 lbs. 0.75 lbs.
15 bunches green onions 7.5 bunches 5.00 bunches 3.75 bunches
1 lbs. garlic cloves 0.5 lbs. 0.33 lbs. 0.25 lbs.
4 gal wine soy sauce 2 gal 1.33 gal 1.00 gal
6 cups sherry wine 3 cups 2.00 cups 1.50 cups
2.5 cups cotton seed oil 1.25 cups 0.83 cups 0.63 cups
4 lbs. brown sugar 2 lbs. 1.33 lbs. 1.00 lbs.
chablis

Combine all and simmer for a SPELL, strain and cool. Then marinate everthing in the refrigerator!

I'm working like nobodies business to get the system fully operational and available for the clubs that want to use is parallel to their current systems. There are some of these :

Okay, latest news :

NMBR vers 7 = operational -

Meaning it can be used to score your own fleets. Accuracy right now is AT MINIMUM equal to Texel/ISAF and UPSN despite the fact that 160 boats (rare or rarely raced boats) don't have a confirmed width input yet.

When this input has been completed the system will ALSO in these cases make a jump in accuracy.

But important point is that input of ALL REGULARY RACED boats are fully confirmed and these ratings are at their best accuracy. (additional accuracy will become available after final tweaking)


So lets see this means that OVER 200 designs are now rated under NMBR and at minimum accuracy to USPN and Texel/ISAF

Go to :

http://www.xs4all.nl/~whijink/NMBR/

To access these ratings.


Wouter

Is there somebody that would like to help us with getting the widths of various confirmed ?

This is a job that can be done from you lounch chair surfing the net.

I got a few helpers now but :

1 is running race data through the system to find problem boats and compare accuracy to yardstick systems

1 is working his butt off getting documentation sorted and publized so that ISAF/Texel/VYC and USPN can read up on the system as well as interested sailors / organisations. (That's me if you haven't guessed that yet)

1 is running over the stuff I produced for errors and anomelies. After a while I get word blindness and can't see obvious mistakes.

We three don't have the time right now to do searches on the internet to find out the width of boats like Nacra 5.0 and 500 and SC20's

Anybody or group of body want to help us out here ?

Sadly no pay just eternal fame and the satisfaction of being part of something that improves you much beloved cat sailing scene !

Mail me at WouterHijink@hotmail.com

Wouter

Wouter,

Is it your intention to keep the NMBR name? I ask because it has been mentioned to me by a few folk that it might be a good idea to add it to Sailwave; which I have no problem doing; I just wondered about the name because something can't always be 'new'...

Good point - That's my pet peeve at work when engineers name something "New" in the system...like "Spider, Transmission, New".

Actually guys I'm of the same conviction.

HOWEVER, I don't think we can change the name at this moment.


I choose NMBR as a code name for the project when still associated to Texel, than afterwards there was no immediate reason to change the name and now because of the rapid developments in all area's I don't think I can change the name without causing disrupting confusion.

I think our best bet is this stick with the NMBR name for now and refer to it in talking as "NuMBeR". When the situation has stabilized enough in a while, say two or three years from now we can put through a name change.

Actually this also one thing I learned at F16 project. I still get mail to F16HTclass@hotmail.com and see people referring to 16HT's and we only carried that name and mail adress for the first 3 months in 2001. So no, I really don't think we can change the name now, although I would love to do that. But we can chance it before the identifier NEW has become meaningless.

Maybe in 2 to 3 years call it WMBR = Wind dependent Measurement Based Ratings ? I should have done that in 2002. To late now. But then again I didn't know in the beginning that the two wind dependent series of numbers would be a permanent feature. It is like naming Chicago Window 98 when the project was started in 1992, you just don't know if it will be launched in 1997 (win 97) or 1999 (win 99) stuff like that.

So please use the name NMBR for now Colin and Jake.

Wouter

(P.S) maybe we can find a new meaning for the N part. I mean we are stuck with the abbreviation but not so much with the acronym. )

Colin, thank you and please read my reply to Jake's post it answers your question.

But I'm in doubt now; What do you guys think, can we still change the name ?

One question to you Colin.

I must admit that I have never worked with sailwave. But I need to know how easy it is to change rating numbers in the input files. We have over 200 designs in the NMBR database now and I'm sure that a few input will turn out to be slightly wrong. You will make a typo here and there when punching in that much data. But Im most concerned about the US boats, several differ sligtly from the EU version and I'm expecting their measurements to come in over the next weeks but I want to have a sailwave version ready so a few clubs that requested it can use it and gain experience. How easy will it be to distribute corrections of this kind ?

Wouter

Max width (I need) is the width measured where the boat is widest, this is not always the mainbeam often the hulls move out a bit more behind the mainbeam and maximum width is found at 2 feet behing the mainbeam.

Can you (the reader) give me the width on the following designs (That you may own yourself and is standing in the garage)

nacra 4.5
nacra 450
nacra 5.0
nacra 500
nacra 5.2
nacra 5.5
nacra 5.7
nacra 570
nacra 6.0

Prindle 15
Prindle 16
prindle 18
prindle 18-2
prindle 19

Hobie 14
Hobie 16 (NOTE, measure on the HULLs and not on the less wide steel frame)
Hobie 17
hobie 18
hobie 18 magnum ; SX and whatever other models
hobie 20
hobie 21

That is all for now as these are the most important numbers that I need now and as it is winter over here I can't get measurements myself by walking down to my own sail club.

If you are really sure about some of these width place post these numbers in a reply to this post.

Wouter, don't worry about numbers changing WRT Sailwave; it's not problem.

How about "N" for...(I literally went page by page in a dictionary listing anything that remotely made sense and stopped at Ni-chrome)

Norweigan
Novel
National
Native
Natural
Nautical
Naval
Necessary
Negotiable
Neighborly
Nerd
Neutral

New Measurement Based Rating System...

I really like "Neutral Measurement Based Rating System"

Name change NMBR ; Input please of all interested!


Lets put it this way I will run down the network and see what everybody thinks and wether official communication has progressed beyond a point of no return. If not that we still can change the name BUT only this week and only when the new name is launched together with the new website that one volunteer is building now. After that we have to stay with NMBR.

One more thing. IF we chance name then EVERYBODY needs to discard to old name and only use the new name. And even correct persons that still use the old name. The transition must be sharp and clean. Otherwise we'll end up with a mess

So INPUT please ! Every goes as long as you examplain why you think the new name fits the system better.

First suggestions

WMBR = Wind dependent Measurement Based Ratings

Spartacus = because Spartacus was a gladiator and Romen gladiators never fought another gladiator with the same armaments. Romans thought it to be very interesting to see which one of two different fighter won. And in addition to that Romans threw monolithic religious messianic (OD sailors ?) persons for the lions to see how long they last outside of their protective environment On the other hand Spartacus lost the uprising against the establishment and maybe that is not a good starting point for NMBR

Hero = after the 2004 martial arts movie, because it tries to pacify the eternal wars between rating system and unite all open class catsailing under one banner and have all speak the same language as the real life emporer Chin, that was depicted in the movie, did after uniting the all the tribes. "all under one heaven". The name China comes from his name.

....

Your turn now !

Wouter

Colin,

please wait out the next days so we have time to think more about the name change. Will give you an final answer at the end of the week.

Wouter

Norweigan? What is that, some kind of cheese? Or was it supposed to be norwegian (not to be confused with norvegia, the other cheese).. Sorry, couldnt resist.

Seriously, "Neutral Measurement Based Rating System" sounds really good to me. It does imply that the other rating systems are not neutral tough.. (but fixated on semantics should we be)

Rolf, lay a tape measure on yout Tornado for me please.

I want to max width of the platform, accurate to the last centimeter. Be careful you have to find the max width first. I think on a tornado you'll find that one abotu 0.5 mtr back from the main beams and somewhere about the sidestays. But you'll just have to find the exact point yourself

Thanks in advance

Wouter

is max width from the hulls or wings (ie H17? H18SX?)

Mary, can you give me the specs on the Hobie wave ?

Boat weight including all gear that belongs to the boat (no thing that belong to crew)

hull length (between bow and stern excluding fitting like pintles)

maximum width

sailarea area (as accurate as you can get it)

luff length of your sail when pulled tight (downhaul ?) at the luff

Mast length

And if your are using a jib also

Jib area

and projected jib luff ( this can often be quite accurately approximated by measuring the distance between top and clew in a straight line.

Thanks alot.


Wouter

If boat has wings then max width is taken over the platform with ONE fully extended wing. Of course measured in the horizontal plane. This is the right measure for the leverage a trapezing crew creates.

So fit only one wing to the boat and hang a plumb bob or something on the far much outer point on the wing near to the maximum width of the platform (no wing) itself and measure the distance between the the point on the outside of the hull on side and the plumb bob line on the other.

Gee man I never realized that NMBR could accuractely rate these boats modified in this way as well. So if one leaves off the wing and another doesn't then NMBR can accurately rate both relative to eachother.

Any FX-one sailors with wings present on this forum ? If so can he or she give us the measurement described above.

Here in the Netherlands FX-one sailors split halve between winged ones and non winged ones But I won't have access to these boats for some 5 months.

Wouter

WICH - Wind Indexed Catamaran Handicaps

"Which handicap system are you going to use?"
"Wich"
"Yes, that's right, which one?"
"Wich!"
"Um..."


PISCH - Parametric Indexed Small Catamaran Handicaps

"Which handicap system are you going to use?"
"Pisch"
"Oh right; over there on the left; let me know when you get back"
"No, Pisch!"
"Um..."

Sorry!

Whoops, my boat is on the trailer in winter storage, so I would have to assemble crossbeams+hulls first.
If you are in a hurry, I can ask some of the guys in Australia or California to do the measurement..

Wouter,

Watch your widths for the Mystere family. Like the Hobie and Performance boats, the Mystere companies in Europe and North America use similar names for boats not necessarily identical. The widths on your NMBR website erroneously list the entire Mystere and Nacra fleet at 2.44 meters or 8.0 feet. Most newer North American boats are 2.6 meters (8.5 feet) while the XL and XXL boats can be very different. Width is a fundemental component of your calculations (I think) so don't go using NMBR on races until you're sure all the specs are right!

Humor: If someone asks for their handicap will they say, "What is my NMBR number?"

Roger, Over....

I am sort of in a hurry, so I think we do need to track down an Aussie or something.

You know what I will ask Stephen Medwell (Tornado-Alive)

Stephen are you reading this ?

Wouter

David,

I'm aware of the issues with the width that is why I'm trying to find a person who wants to spend a few hours looking up all the widths. It is not difficult but it needs to be done. Note how the 2.44 mtr are printed in FAT characters indicating that these are the unconfirmed default values. So anybody want to help us (David, Mark, Peter, Jake, myself and an anonymous) out here. Only a few hours of looking up / acquiring the width data on boats listed ?



But we need to know exactly as I think Inter 17 is 2.55 mtr and the FX-one is 2.5 mtr.





Width is not an input factor fro the sub trapeze group of ratings so these can be used without any problems and this group is already more accurate than the two other measurement ratings systems as I have eliminated a few "problems' that these systems suffer from.

It is only the "trapezing" group dat suffers PARTIALLY from the incomplete width data. Ofcourse the factors like crew weight (double hander / single hander) and differences in sail area time mast height ARE accurately included. So I dare say that the NMBR trapezing group is also more accurate than the two other measurement rating system already. From tests it appears that it also beats yardsticks systems.

So what am I arguing here ? First we are already "accurate" to "more accurate" than others despite the fact that we haven't reached full possible accuracy yet. Secondly why choose to NOT use a more accurate system even though it has not reached it maximum accuracy yet. There are already benefits in using it now and there will only be more benefits in using it later.

I would love to start with all the specs right but for that I need a volunteer that looks up all the width data.

I'm hoping that we can get a few widths taken at Tradewinds so that least all the regulary raced boats all have highly accurate ratings.

And then of course during 2005 we will get out that last bit of accuracy by fine-tuning the system. By this I mean things like :"IF we find that spi's improve performance more in light winds than in heavy THAN we can adjust the ratings accordingly" . But truly by this time we are talking VERY high accuracy levels.

Ohh before I forget that is why I posted the message about the nacra, prindle and hobie boat. Just to get a head start.

Wouter,

What is wrong with "What is my NMBR" ? (pronounced as "what is my Number ?")


After what you are saying is correct both in meaning and grammar.

"What is my New Measurement Based Rating ?"

Wouter

NMBR is pretty well under way now, look at http://www.xs4all.nl/~whijink/NMBR/NMBR_vs_7_tabled_ratings.xls

for the intermediate results. Over 250 design and design variation rated with most all of the frequently raced boat having accurate width data. Only some rare boats have still some temporary data but how many times are Topcats or aquacats raced ?


Also several specific US designs like the Isotope, Wave and Nacra 5.5 uni have been added.

But most importantly NMBR has a rating for the US I-20 !

I'm still looking for good data on the Nacra 6.0 NA, the supercats and the CFR20. So any help here will much appreciated.

To any clubs and individuals using the system on a trial basis. Please report any offsets or anomelies to me. I will immediately investigate the issue and device, together with he others, a solution. However expectation is that only in the truly rare cases you will find any issue. Mostly because we also don't know everything about an aquacat or aesticat 500.

Good luck and I hope your club racing improves with the new system

Please note a name change is in the works for NMBR and soon after that it will be taken up in Sailwave.

Wouter

Everybody is allowed to vote in this one.

It is about the new name for the NMBR rating system. Under this name the system will be put up for evaluation at the various national sailing organisation as well various rating systems. The last so they may learn from it.

NMBR meant "New Meaurement Based Ratings" But that was only its development code name. It's project name. We now need a name that is easy to use and that is a good identifier for the system that was developped in the NMBR project.

I will have myself be guided by the outcome of the vote, while still reserving the right to choose a different name than the winner.

The list supplied in the vote is a listing of the better suggestions that were send to me.

Please note that a name like OCR will be used as "OCR rating system" while a name Like Socrates will be used as "The Socrates number for design ... " Or as in the case of SCORING "Your SCORING number is ..."




For a read-up on Socrates go to :

http://www.philosophypages.com/ph/socr.htm

I like the fact that the Philosopher Socrates is characterized by :

"In his use of critical reasoning, by his unwavering commitment to truth, and through the vivid example of his own life, .... Socrates set the standard for all subsequent Western philosophy."

" ... insistently questioning their unwarranted confidence in the truth of popular opinions, ..." (My boat is fastest anyone ?)

" ... Socrates pointedly declined to accept payment for his work with students ... "


Aren't these great creeds by which the new rating system and open class racers should live by ?

And no I'm not the one who thought up this name. It was Norbert Kooij, an experienced Race Officier here in the Netherlands.


Now lets all vote quickly so that Colin can implement this new rating system into Sailwave so we can use it in 2005


Wouter