I think the dart hawk is one of the most misused examples of the catamaran scene. That design will go very well in todays F18 fleet if only somebody took the effort to put a decent rig on it. The hull design etc are just very good. This boat was killed because of other factors, like a british pound that was overvalued making the boats very expensive to mainland europeans and the fact that it good a bad rep because no professional crews were sailing it. This statrted the rumour that the Hawk was a slow boat because the crews that did sail it where your average recreational sailors who understandibly didn't finish very high in the professional sailor dominated F18 class.

Personally I think the Hawk to be a better platform then the Nacra Inter-18 and Nacra F18. It just needs to have a modern rig.

Wouter

BUT it can be developed and so should be getting faster. But now as the Texel system is (still??) based on the old T without kite and twin wires; anyone sailing an old (Standard T I'll call it) is stuffed.

There is a basic problem with any rating rule that pegs it's starting point to a development class (or box rule). The development class (or box rule) boats should get faster over time as the sailors make material changes to the boat which makes it faster. All sailors should be getting faster in their boats, but with a development class, there is scope to sail better and also make the boat faster. You cannot make a One design class like the Dart 18 any faster as the rules preclude it.

Again I make the statment that the Tornado is not a one design as the rig setup can be different. Thus it was a mistake to peg texel to this boat.

Better sailors should always (IMO) win, but any sailor of a development class (or box rule) also has the ability to improve the boat.

Consider another example, Simon and Wouter sit down and produce "rating rule 1 - RR1" and decide to peg the rule to the new boat I am developing (The Stealth Hungry monster design - SHMD) which will rate at 1.00 (it looks like the boat will rate about the same as a Tornado 2001 under SCHRS and Texel for info).

My boat has a Alu mast as I'm not feeling rich (but the same section as the F16's so it's a wing)....

The rating rule takes into account all the same things as Texel and SCHRS (roughly) and so the handicaps are SCHRS 0.95, Texel 0.95 and RR1 1.00. Under all 3 systems I have handicap that I understand and so off I go sailing and have loads of fun. I'm not winning any races as I'm still learning how to set the boat up. I'll live with that.

After a season or so I decide I should have had a carbon mast as I need more control / lighness up top so I buy one (and add some lead to the boat to keep all up weigth the same) and now I have a nice carbon Wing mast and it makes a massive difference - I have a faster boat because of this; I'm now winning everything (I know it's not probable, but bear with me). So I changed the Alu mast for a carbon one and I'm now winning, but my handicap is the same.

I've spoken to some of the Tornado boys and they say that the Carbon Mast is "always better"; more power in the light stuff, More control in the heavy stuff, We are going faster in all conditions.

[color:"red"] But the Tornado Handicap has not changed!!!!!!!!! [/color]

Is this right ?

Now the supporters of Portsmouth, might, at this point, jump in and say that Portsmouth deals with this becasue as the Tornado's are winning, then the handicap will come down as the results data is collated after each season. BUT it is too late by then. The winning is done.

The whole point of SCHRS and Texel was that you can turn up with anything, get it measured and then be allocated a rating that is fair.

SCHRS had a penality of one point for a Carbon mast that was removed some time ago, perhaps it should be put back......

Question for Wouter, Did Texel ever have a Carbon mast factor?

No it isn't. Texel does include teh difference between single traping and double trapping and apparently it doesn't make that big a difference in the speed of the Tornado. Which is not beyond logic, the difference between the skipper hiking at 3 mtr is not much different then having him trapeze of 3 mtr. If they boat were to be 2.30 mtr wide like a dart 18 then the difference will be more significant.

People, we are argueing "gut-feelings" against founded mathematical relationships here. Now I'm not saying that math is always right, but I am saying that "gut-feelings" are far more often wrong.

I also say that when a crew takes a competitive 1999 Tornado and slaps a 2006 kite on it that this crew will indeed be very close to the fully optimized 2005 Tornado. 1 % difference in rating may be a bit small but I don't expect the difference to be beyond 2-3 % anyway. The changes to the Tornado were not THAT significant. It is still the same platform, with the same boards and fittings. I must say in this respect however that TEXEL needs to remeasure the new carbon masted Tornado's as the current Tornado rating is still for the ones with an aluminium mast. Of course the boats because nearly 7 kg;s lighter overall due to the carbon masts. Thhis will lead to the Tornado with carbon mast to be rated as 93 , which is 7 % faster than the classic tornado (no spi) and 1 % faster then the fully pimped 2005 tornado with an aluminium mast.

Lets not forget guys that the carbon mast on the Tornado is a rather new development. I expect the rating to be corrected for it before the round of Texel 2006.





Material chances in themselfs are very ineffective in making designs faster. Most materials changes are made to keep a mainsail longer competitive. A new dacron mainsail will be just as fast as a new pentex one. After a year of hard use they may not be, but when new they will be.

The same for hull material etc.

It is true that the development boats get faster over time, but this is more due to design changes like squaretop mainsails. However this is not a practical way of looking at it. It is better tho regard the modern designs as stationary and regard the non-developping OD classes are becoming slower in comparison. In my own rating system I proposed giving OD classes without development an extra correction in their ratings for this. This is far more practical to do and more fair. Why because who really races dead OD in open class regatta's classes anyway ? The biggest requirement of an rating system is to rated the popular racing designs properly not the extinct Prindle 16. In addition the owners of 10 year old Prindle 16's and Hobie 16's expect to be competitive with their run down boats, that is not an issue that a rating system can solve; it can only rated new boats properly or risk giving owners of new boats unfair advantages.

Having said all this I'm also convinced that design chances like the squaretop sails and selftackers are only causing offsets of about 1%-3% at maximum. Compared to the 30% -40% chances in performance due to different level of sailor skills, I think these material related differences to be rather negligiable. The new development are not making the formula boats that much faster in absolute sense. 1 % difference is already 40 second per hour difference. A significant gap in a F18 world championship racing when fighting for place 1 to 3 but not far any other placings.

People are often making far too much out of material differences. Its simply not that important in overall performance.

Also the best approach to make a Texel system really fair is to group modern design into 1 fleet and to group the OD and dying classes into one seperate fleet. Now you have solved this issue al together. This trick is often applied. Pretty much this is possible because Texel does rated modern design very accurately to other modern designs. The same for older designs.





Well, if Dart wants to optimize their profit margins and source out their sailmaking to some vietnamese sewing company then that is just not a problem of the Rating systems. Bad quality should be an input into a rating system. Especially since the same situation will even lead to unequalness and unfairness within the OD class itself. And there no corrective action is taken as neither. We all know of examples where a sail from a certain batch was a winner while others were not. No system is going to accurately deal with bad quality control. Nor such any system try to do so.

This leave the development into new shapes etc. I refer to my earlier answer above. These developments are not a big as many believe it to be. See Tiger versus Capricorn. A difference may well exist but it will not be very big. I personally think making a rating system alot more complex in order to accurately rate this small chances is beyond what is desireable and practical. So yes in this respect it is a choice to make the rating system more like a good estimate rather then a really accurate one.





The tornado was rather fixed in its rig before 2000. It was certainly not as open as the formula classes. I seem to remember that the width of the sails at different heights were ruled upon. Please everybody, research the matter before making wild claims.





Sure but is it significant beyond say a certain margin ?

If so is it practical and desireable to expand the rating system to correct for this ?





That is what people believe but if you started out with a proper alu mast then the difference maybe small indeed.

This leads us to a difference problem however. The difference between an heavy alu Hobie 16 telegraph pole and the lightweight alu F16 superwing mast is FAAAAR greater then the difference between an alu F16 mast and a carbon one. If we are to take these effects into account then we should do so with respect to masts that have no diamond wires and outdated crossections. Not between alu and carbon masts that are in all other respects the same.

Actually I had a crude correction factor in my NMBR system for this issue.


Maybe we should all realize that Texel is not perfect, we can all name situations were things may go weary. HOWEVER the discussion was initiation whether a yardstick system would be better. The answer to that is that while Texle may not be perfect it is more accurate then a yardstick system. We can make Texel more accurate still but then Race committees and sailors will bitch about teh fact that it is too complex and to cumbersome to use. Notice the Texel 2005 to texel 2006 change and the causes for that.

I don't see much point in proving the fact that Texel isn't perfect. That is a given.

We should focus on other things.





No wonder, they saved 10 kg on the overall boatweight as well and all carbon rigs have spanking new mainsails. A new boats is "always better" if not "feels better". Then of course the professional crews chance over first leaving the less skilled crews as the new (biased) reference pool. Now I expect some improvement, indeed, but the magnitude may well be smaller then what is suggested by feelings.

Note that the tornado class rules DON't state an overall minimum boat weight ! The minium weights are specified per component and on the platform. In the way of masts only a tip weight is specified and the one for the carbon mast is less than that of the Alu mast. In effect this means that the Tornado has lowered their overall boat weight without many people noticing it. I hope the rating committees are aware of this,




That is mostly because its carbon mast introduction is very young. No rating system has had the time to react yet. Texel has to measure the new overall boat weight first.




No, but soon Texel will have reacted while yardsticks will take years to converge to a new number.




No if anything this penalty should be had to differentiate between masts with diamond wires or not. Or even between teardrop shaped masts and wingmasts. Material is of only a minor concern.




No

Wouter

You can view it like this, but the devopment c lasses are getting faster. So you propose to change all the OD classes numbers instead of a few development classes. Sounds like you are creating work here.



Agreed.



I've been sailing in races where 40 seconds has been the top 20. I think I'd have the 1% extra speed thanks.



I never said that Dart should do this. Don't put words in my mouth.



I was talking about the 2001+ Tornado. Mainsail shapes are different. It's not a wild claim, why else are poeple spending money on flat tops, Round tops and various cuts between this. I agreed it is not as open as a formula class, but it's still a development class.

Take a look at this picture, are all these mainsails the same. I think not :

Well, you know what.

I've done my work in developping a better rating system and caused some well known rating system to change after being stationary for many years. By domino effect it looks like SCHRS will follow suit. I think I've done my share in this field and I'm willing to keep silent now and let you have the last word.

Good luck,

Wouter

I'll be interested to see what the rating for the F18 Capricorn comes in at then when it gets measured.

Does anybody know/rumour/gossip if the SCHRS committee is going to introduce a width component into the formula?

Scooby Simon,

I know the SCHRS uses weight, what I was getting at is it's ability to use the weight correctly as the wind speed goes up.

I do believe SCHRS knows the short comings of the rule, but like all things it comes down to money and who do you pay to update the rule.

This has turned out to be a good debate, wonder if the SCHRS lads are reading this?

Why does the EU need two measurement rating systems? ... Is this ISAF’s heavy and stupid hand at play?
Is this just BS national politics and some ego driven personalities at play… There are only a limited number of things to measure and a handful of ways to measure them. The proof is in the pudding where people instantly figure out if the rating differences are fair or not. If the system is fair… it gets adopted. Why doesn’t SCHRS just throw in the towel and go away since texel appears to be more popular.… (True???)

Why pay money for a service that Texel accomplishes with volunteers and now they seem to be responding to the users critiques by issuing two updates to the system within the last two years wheras ISAF is contemplating their collective navel. (All of the Portsmouth yardstick committees are volunteers as well). Who is complaining about the current Texel ratings as being off base and unfair to some.

Mark

Is it Fair?:




Is it fair
for sailors with OLD out of production designs to have a rating continually adjust upwards because their boats are old and soft and the sails were shot years ago.
Currently in Portsmouth … This can and does happen! Sailors with old boats believe that their rating SHOULD be adjusted upwards relative to the hot new boats. Not sure but in measurement areas, Can this sailor ask for a new rating because his boat is much heavier then the original rated boat?

IMO… Portsmouth should announce a rule that Ratings will NOT update to slower ratings for a boat class ONCE it has stopped holding national or regional championships. The reason is that the assumptions of the Portsmouth system are violated and the outcome would be unfair. Measurement rules should not re rate a class boat unless the owner makes significant changes and pays for a new individual boat rating.


Is it Fair:
To list the original Dart Hawk or Inter 18 as slower then the current F18's (US Portsmouth). However, If you grabbed the latest and greatest rig for the boat and updated the bits ... What should it then rate? Are you rating the rule… OR the designer’s best guess at optimization? If you rate the designers boat.. then you need to rate each individual boat class within F18’s (Scooby’s suggestion). …If you change a piece of equipment in the rated parameters, do you then have to get individually measured?

IMO… you rate the rule…. The F18 rule has not changed… so the Hawk owner is just like the owner of a 15 year old P16 with 15 year old sails asking the Portsmouth committee for a slower rating… NO you can’t do this… that is a slippery slope to destruction. In any system… you assume the boats are maintained in racing shape, good sails and actively raced by a population of sailors around a balanced course… you can’t adjust for old age and dated equipment. The Hawk owner can upgrade his equipment or not and then pay for an individual measurement. In Portsmouth regions, You would need to have the Hawks racing in sufficient numbers in their original configuration at a regional championship to collect valid data. If not… they should use the measurement rating and interpolate the data into the US Portsmouth system. If some parameter is NOT spec’d by the F18 rule, then you should sample the representative F18’s every two years and re measure and recalculate the rating. This should keep the rating current and fair without stepping on the class or formula rules.

Is it Fair to have a Tornado with an Alu mast rated the same as a Tornado with a carbon mast which performs better in all wind conditions (you can't break it by dumping the sheet in a big blow down wind... so now you play it eg faster.) AND it's lighter with less inertia at the top.. The Tornado Class has tightened and tightened its rules to become virtually one design so as to maintain their Olympic status. Development occurs in jumps… (carbon mast) and in increments.. (better sails and sailing techniques).

IMO, This situation differs from the F18 example. In this case, the class changed the rule and allowed a tightly regulated carbon mast while grandfathering all of the Alu masts. So, I think that this change warrants TWO entries into the measurement handicap table giving you the Tornado Classic, Tornado Alu, Tornado Carbon
Since the Classic is not raced in nationals any longer… I would FIX the Portsmouth ratings and just monitor the race data. Once the Alu mast stops showing up at the nationals or after the rule change. … It’s rating should be fixed and not allowed to drift slowly upwards either. The measurement rule will calculate the effect of the lighter mast on the rating and publish 3 ratings.

The changes in sail design and techniques are part of the game… Perhaps these types of classes (F18, Tornado, Prindle 19’s) should be hit with a small fixed development correction factor in a measurement rule that strictly controlled SMOD one design class don’t have to use (Nacra 20, Hobie 16)

The A Class differs from the tightly controlled Tornado, and the more loosely controlled F18 box rule. In that their class rule does not specify many of the parameters rated in the measurement rules. The solution would be to require periodic measurement of 3 representative class boats every couple of years and add in the fixed development correction factor. This should keep the actual boats on the water rated fairly with respect to the rest of the world. The older A designs are just like the old F18’ and Prindle 16’s and can’t ask for a ratings break IF they still compete in the one design regattas. If development kicks them out of the game… they can be listed separately like the Tornado (alu) or as in the USA. A class (200 or greater)

Finally, what should you do with new ONE off boats or radical upgrades of older designs or classes with fewer then 20 boats racing. The CFR 20 is a good example of a ONE OFF while one Supercat 20 was radically upgraded in the states and the M20 has 2 boats while the F16’s are just approaching critical mass in the USA 8 boats at an upcoming regatta..

In Portsmouth Regions, we should not pretend that we will get a fair rating relative to the other classes for these boat through statistics! (Every assumption of the Portsmouth system is violated)! We should change the rule and state. These boats will be rated using a measurement rule, interpolated into the US Portsmouth rating function of similar boats until the minimal criteria are met (number of boats at national championship, etc) any changes that you make to your boat that effect a rated area result in the need to re-measure your boat. Once you hit the Portsmouth criteria., we will use all of the recent data to calculate a fair rating. In measurement areas…the owner must pay to have the boat individually measured to secure a rating and take the development class hit.

AS always… comparing apples to oranges is tough. So comparing spin to non spin is always tough. Comparing modern to classic designs is easier but still tough.

In the end... you have to decide what is the fairest solution and get people to agree.

You are not rating the rule, as the F18 rule (as I have said a number of times) does not measure the same things as SCHRS.



back to my other example again; I build a boat that does not have a limit on dagger board size (as per F18), it does not have a mast height limit (as per F18) and it does, but does have a "beam to mast top limit". For my first boat I build it with very small daggers and a very short mast. THis boat then (say) rates to 100.

We will call it the scooby1 design

I then decide that I messed up my boat design and so add very large boards (that are not controlled in my class rules as this will make it point much better) and I also go for a much taller mast). Under your proposal these 2 boats whould rate the same. however the 2nd version WILL be quicker; maybe only 3-5% quicker, but it will be quicker. Fair, I think not.



Which is exactly what SCHRS is going to be doing I believe.

Old F18's will rate at 1.01 and new(er) boats will rate at something else for racing using SCHRS - I've never suggested the F18's should handicap race at their F18 championships.



This is why SCHRS and Texel exist; once you get the measurement criteria correct, you can fairly rate these boats by just measuring them. Wouter said above that people turned up with what they thought were "ratings" beaters at Texel and it was not the case. Ergo the rule works.



So you want to use a rating rule and a "portsmouth rule" !!!!!!!!



I don't; SCHRS and the ISAF do;

I would be happy to use either SCHRS or Texel assuming they are coming up with similar answers.

Simon, I ignored this comment until I had the usual Saturday bottle of wine
The Spitfires have a "One design" circuit, with 25 boats at their Nationals. Apart from JP, as far as I know, no other F16s have ever challenged the top Spitfire sailors at open events.
I hope that some day the Spitfires will enhance the F16 fleet, but at the moment there is no contest in the UK or France.

Yes... the data set is too slow to be generated and the pool of sailors too small to generate an acceptably fair number. Since the principles that a portsmouth system depends on are not valid... you need another solution. You could just make up a rating like PHRF and then go from there... or you could use the measurment rule until the conditions change and you have met the criteria.

This is my solution to balance the reality on the ground with the ability to implement it.

I must say... it sounds like a nightmare trying to re measure every F18 and certify that the equipment that an X brand of F18 now has... is what all of the other F18's of t brand X also has.

Or will everyone have to have their boat's measured to go racing?

There have been more instances like that. One just last september in Netherlands, but I don't see the point in highlighting this every time. The spitfires keep mostly to themselfs in the UK and in France/Ireland we don't have an F16 class yet. Outside these three nations the Spitfire class is non-existant. Spitfires were sold to a number of other places but never in the numbers to be able to form a class of their own. Holland is one such nation. I count 2 spitfires here. One crew we have approached to invite them to join us in F16 racing but he said that he was only interested in recreational sailing. The other boat is rarely used and for sale. This example is not to put down the Spitfire class, I think them to be excellent boats, but to show that the two classes are pretty much seperated from eachother. For this reason we don't see much direct comparisons; it is simply not possible. That is with the exception of the UK but here the Spitfires have a rather strong class and want to maintain that.

Personally I don't care whether they participate in F16 events or not. The invitation stands. If they don't want to then they don't want to.

With respect to the spitfire design. I think the design to be faster than the SCHRS rating is suggesting. It is a fast boat that will indeed run with the F18's;

Its rating is 1.02 under schrs (F18 = 1.01) when punching in :

Crew = 2
weight = 135 kg
length = 5.00 mtr
mainsail = 15.5 sq. mtr.
mainssail luff = 8 mtr.
jib = 4.5 sq. mtr.
jib luff = 5.5 mtr.
spi = 18 sq. mtr.
daggerboard = 0.19 x 0.76


However under schrs is has 1.04 as rating because it is measured at :

Crew = 2
weight = 139 = (135+4)
length = 4.98.00 mtr = (5 mtr - 0.02)
mainsail = 15.45 sq. mtr. (= 15.50 - 0.05)
mainssail luff = 7.9 mtr. (= 8.0 - 0.1)
jib = 4.45 sq. mtr. (= 4.50 - 0.05)
jib luff = 5.43 mtr. = (5.5 - 0.07)
spi = 18 sq. mtr.
daggerboard = 0.19 x 0.76


Now less than an inch difference in length, about 1 sq.ft. less sailarea and 4 kg more boat weight are not going to make the boat 2 points slower in reality. But it was enough to put the boat over the 1.0351 rounding off boundery so it gained two extra handicap points as a direct result of these offsets. Sadly that is possible with measurement rating systems.

But anyway, I personally regard the Spitfires as only a fraction slower then the F18's and pretty much on a par with the best of the F16 designs. So I don't think that fear of underperforming is at all a likely cause fro Spitfires not attending F16 events.

Wouter

You are making error regarding F18 rules

-1- mast height is limited in the F18 class rules (to 9.15 mtr to be precise)
-2- SCHRS does not rate daggerboard area, only it aspect ratio (as I wrote earlier in a different post)

For these two reasons alone your example is wrong. As a matter of fact by having small boards you can NOT get a slower handicap at all. Actually you get a handicap that is rather too fast for our boat, the one that is accurate for a design with normal sized boards.

Scooby, please forgive me but research the matter more thoroughly before making baseless statements. You are only creating wild rumours and correcting these obvious errors in your reasoning is simply a waste of time of the others.

So please, study the class rules of F18/tornadp class and others and investigate how SCHRS (and other systems) really work internally.

Wouter

Oh FFS I give up;

I made one small error on aspect vs area. People know the Capricorn is faster and all SCHRS is trying to do is equalise this in the rules. I believe SCHRS is going to address this. I don't know how, but I am assuming each F18, so Hawk, Capricorn, Tiger, Nacra (old), Nacra F18 and Illusion etc will have a SCHRS number for handicap racing.

I re-state again. The F18 rules do not measure and control the same things that SCHRS does; thus there is a cproblem with the handicap of the F18 within SCHRS. SCHRS are addressing this.

Wouter I had not seen the 9.15mtr rule in the F18 rules for the mast; However, there SCHRS parm is the Vertical luff on the mailsail (and Jib) and this is stated at 8.5 (5.2) in the current SCHRS calc. Are you stating that all mainsails on f18's are 8.5mtr luff and so this does not need taking into account (I don't see that you are).

I am not a member of the SCHRS ctte or do I have any control over the rule. It's not my rule I just want to discuss it and it's short comings with regard to the F18 situation and how (I hope) it will be fixed.

I believe that we are getting bogged down in scantics; I'll apologise for my minor mistake on area of plates and the max mast size.

[color:"red"]
BUT, please consider this:

"Are the current crop of F18's (Capricorn, Illusion and the newer Tigers) faster boats than the old boats with old rigs ?"

I say yes, the reasons I say yes are :

Development of the class as a whole, construction and mast shapes and the like, mainsail shapes, VLM and plates.

so, should the handicap's of either the F18, or all other boats, be adjusted in the light of the fact that the F18's have got faster?

I again believe yes.

SCHRS and Texel were created to allow new designs to be given a rating "out of the box" and perhaps the rating parms need changing

[/color]

Discuss.

I wonder if all the Spitfire's are now shaking in their boots after Wouter's update on their SCHRS rating review. So if people know that this boats is slow in SCHRS and fast on the water do they buy the boat for the easy win? Or do they race as a one design fleet?

Wouter how does Texel look at the Spitfire?

Looks like a lot of classes under SCHRS need adjustment's

They prefer OD racing as far as I can tell.

We must allow ourselfs to overstate a 2 points difference under SCHRS (or Texel); is not a major difference. About 1 min 12 sec per hour. Now this may sound like alot but people often forget how quick time passes on the water.


Spitfire under Texel is about the same : 104 (spitfire) to 101 (F18)

Both system use very similar input values; I haven't investigates this in detail (as Texel is hiding their unrounded handicap numbers now) but it can be that Spitfire is again just on the right side of the rounding off boundery.

Wouter

Scooby,

I would like to state first that I feel we are on the same track in most aspects relating handicap systems. My current discussion with you is mostly to get the details right as well. No disrespect intended.




I'm sorry to say but you were making more mistakes then that. And you are missing the way in which the F18 rules are indeed fixing the schrs/texel handicap numbers. In addition the Texel handicap number for F18 has come down over the years and you don't give that credit.





There are two arguments to be had here. First f18 class has become faster over time relative to old OD classes. While this is more limited then people often think; it is definately truthful. SCHRS didn't not change over time. Texel however had F18 transition from 104 in 2000 to 101 in 2006 while keeping the old OD classes at the same ratings. Same applies to other modern boats like F20. By the way 3 points rating difference is 1 min 48 second increase of performance per hour. Nearly two minutes. I think this to be rather accurate.

Now people will also understand why I prefer Texel over SCHRS. Texel is just alot more responsive to changing conditions in the catamaran racing scene and stays on top of things.

The other way, is that newer F18 are supposedly faster then the older F18 designs. This is a difficult argument as it is not as straight forward as it might seem. Grab and old dart hawk and slap an updated rig on it and you'll have a competitive F18 again. So yes while it is true that the hart hawk design of 1995 (with rig current for that day) WILL not be competitive in the more serious F18 racing this doesn't mean that an updated version with new sails etc won't be competitive again. Naturally it is very difficult for a rating system (either Yardstick or measurement based) to discriminate in this latter example. It will simply be undoable. Therefor both systems require the crews to keep their boats in excellent condition if the rating is to be fair. No rating will be fair to any beat up blown out boat.





I don't think this to be advantagious and really don't expect this to happen. Why because the measured specs of say the Inter-18 are really not much different at all from those of the Capricorn F18. The used rating formula can not discriminate between the two and I really don't believe that an inter-18 with a new and modern set of sails is that much slower in reality anyway. Alot of the F18 development is to be found in components can be put on any older design. If so desired the complete Capricorn rig can be put on a inter-18, same with the rudders and selftacking rig. Who is going to check that a boat that started life as an Inter-18 is still an inter-18 after several years of F18 racing (modifications) ? If its an F18 then it is an F18. The nacra inter-18 class OD simply does not exist. At least not in the way that I actively controls the modifications to the design.





You can state this another 100 times Scooby but that still doesn't make it true.

Now lets turn this thing around. You tell me what you preceive as the measurements of a rating beating F18 and I will first check whether it is F18 class rules compliant, then whether it is at all practical and then most likely show you that the SCHRS is within 1% of 1.01. 1% is the official uncertainty margin because of the numbers being rounded off.

Give it a shot Scooby and show us.





Okay lets look at this in detail :

For the full F18 class rules go here : http://www.f18.nl/index.html?Frame_Technical.html&Frame_ClassRulesF18.html

B.2.1.2. The maximum distance between the top of the forward crossbeam and the bottom of the upper measurement band of the mainsail shall be 9100 mm. See diagram B.2.1.2.


I wrote 9150 mm earlier but the correct number is 9100 mm. So the mast is limited in length unlike the A-cats.

This also severely limits the mainsail luff length as a low boom is a serious impediment to the crew, especially under spinnaker sailing. This means that on average the mainsail luff length of an F18 is 8.5 mtr. Designs with less will never be rated faster when using their correct amount so we'll ignore those boats for now. The maximum practical luff length on an F18 is 8.7 mtr. And that is absolute maximum as only 40 mm clearance under the boom is really too little. You can't get across on your hands and knees then you'll have to tiger crawl underneath it. Do that with a spi sheet in your hand.

So lets now see what kind of difference going from the average 8.5 mtr to 8.7 mtr makes.

8.5 mtr. SCHRS rating (unrounded) = 1.006191
8.7 mtr. SCHRS rating (unrounded) = 1.002552

a difference of 0.003639 = 13 second/hour racing. = 1/3% = way less then 1 %

This difference is negligible. it is also well in the order of the noise that is enclosed in the rating formula, meaning that we can't say whether this difference is the result of the longer luff or the error made when the rating formula was derived.

So you see while the F18 rules indeed don't actively rule upon the mainsail luff length (as the F16 class rules do), the other rules and what is practical in real life do very much limit all F18's to as good as the same luff length.

From an engineering point of view I can tell you that those 200 mm extra luff length so low on teh mast are really not efficient in any way. Their is far to much turbulance due to the hulls and trampoline that low and the windspeed itself is much lower there then compared to 2 mtr to 9 mtr up.




Agreed. This is why I prefer Texel. Getting things done with SCHRS is a serious pain in the neck. Texel is much easier to talk to and much more accomodating.





Yes and Texel corrected for this by having the ratings go from 104 to 101 over the last 6 years. SCHRS did nothing.




Most of these changes can be put on older F18 designs as well, making them alot more competitive again. Only exceptions are hulls and daggerboards. Rudders, sails, mast etc are all exchangable.




Class rating as a whole, YES. Individual F18 ratings, NO


Wouter

Good, that is what I hope SCHRS will do. Excellent.

That is what I am trying to get to. The F18 has got faster, so the handicap needs to change. Simple as that.

If the SCHRS rule needs to change what it measures, so be it. If the rule needs to be re-worked so be it.