Just a few questions, this is the rule governing mast tip weight?

1.4.5 The weight that is measured at the mainsail hoist height of a mast lying perfectly horizontal with its base supported at the bottom edge of the mast section is referred to as the "mast tip weight". The minimum mast tip weight of a fully fitted mast, excluding standing rigging, is set at 6.00 kg for reasons of seaworthiness and to guarantee fair racing.

So what it is saying in other words is that where and how the mast is weighed will actually give the approximate half weight of the actual rigged mast?
If that is correct??? Then a fitted mast, less its standing rigging, has to have an approximate minimum weight of 12kgs (for the whole of the mast with fittings)?
(Does that also allow for the spinnaker halyard to be included in that weight if it is an internal halyard?)
If the above were correct, then by my calculations, even a fairly standard carbon fibre mast with fittings, would fit that minimum without having to add extra weight. I would have thought that any standard aluminium mast would be much heavier than 12Kgs any way
I suppose what I am asking is, assuming that my assumptions are correct (and I stand corrected if they are not) what is the point of having a mast tip weight as it would not effect anyone’s personal choice as to whether or not they wanted their mast in carbon or aluminium (other than a cost differential).

The rule says "... a fully fitted mast, excluding standing rigging ... " This includes all fittings such as halyards and trapeze lines (in normal position) in the measured tip weight rule. ONLY the fore and side stays are excluded from this measurement.

This applies in all cases, c.q. also when the halyards are not internal.

The fully rigged Alu mast are now at about 8.00 kg tipweights if I remember correctly. 6 kg tipweights thus allows the carbon masts to be 4 kg lighter in the mast tube section assuming the same "fitting out" of the mast.

This should be pretty close to what can be had with carbon masts, where the extreme cases fall outside of what the rule allows. This was the intention of the rule several years back. Limiting the gap between alu and carbon as well as preventing "fully optimized" masts that break after a capsize as is encountered now and then in the A-cat class. By limiting the weight savings that can be had and making it far more attractive to have more material in the mast then lead at the top we sought the reduce the pressure on the mast builders to find the absolute edge.

To PTP, I seem to remember that that carbon 18HT mast weights about 15 kg's, compared to under 10 kg for A-cat masts. So that carbon 18HT mast is not the lightest that can be had with carbon but it is definately dependable. The same situation was sought for the F16 class hence the tip weight rule.

Wouter

From a previous topic, I believe you are correct. In here somewhere I think

A standard taipan mast section weighs more than 12kg...I seem to recall 14-16kg...

A typical structurally sound carbon mast for F16 would weigh something like 11-12kg...

The above discussion suggests 4.5-4.75kg tip weight for A-class masts.


So removing the minimum tip weight, which will be approximately half the overall weight ignoring diamonds etc., will have very little effect. Except that for carbon masts the distribution of the weight in the mast, hence the stiffness distribution, can then be altered, which would also alter the tip weight.

For example, someone may want to stiffen the lower mast section and soften the higher mast section, this would lower the mast tip weight.

I think the mast tip weight should be left alone until a couple more seasons are under the belt of the F16 rules before fiddling around with them.

As you alluded to, the actual tip weight wouldn't drop that much if the rule was abandoned (maybe 1-2kg total), so what's the harm of making the mast a fraction stronger. At 10kg, a 2kg total weight reduction, I believe it will be lighter than an A-class mast!!! They already break those regularly without a kite or jib!

In terms of being able to right the boat, 1-2kg of weight saved in the whole mast isn't going to be the difference that enables a light crew to right the boat. The water on the sails and in the mast, the prevailing wind (or lack of it) and the righting technique will be much more significant factors.

From experience, in 5 knots of wind, a 70-80kg skipper cannot right a taipan single-handedly. But with more wind it can be done very easily because the wind can lift the sail off the water.

From discussions I have had. A carbon (and VERY robust) mast can be made at around 5kg tip weight.

roughtly speaking the tipweight for an F16 can be estimated by taking halve of the weight of the bare mast section and adding 0.75 kg.

For the Superwing alu mast this comes out at 15/2 + 0.75 = 8.25 kg. I've seen several measurements and they are indeed 8.00 kg and just over.

Ever since this carbon mast discussion started back in 2001 a good rule of thumb for carbon F16 masts was 1.1 kg per meter mast section. Thus arriving at : (1.1 * 8.5)/2 + 0.75 = 5.43 kg tipweight. Despite the fact that I can't really quote actual measurements as per agreement I can say that I have yet to be made aware of a carbon F16 mast that is significantly below this number. Even the newest carbon mast that I'm aware off is said by the owner/builder to be 400 grams under the 6.00 kg tipweight. At this time he uses no mainsail halyard.

The above data comes from two well known carbon mast builders, although the dates of this info are 2001 and 2002. (the newest carbon mast mentioned above is an exception and this data is from 2007)

Naturally an 4.25 to 4.75 kg tipweight carbon A-cat mast can be used on a F16, but I wouldn't expect that to be dependable when 2-up sailing under spinnaker as seen at the Alter Cup. As the saying goes, every vessel claims mastery of floatation in a calm seastate. As of yet I have trouble understanding how a 2-up carbon F16 mast can have the very same tipweight as the modern A-cat masts and still be very robust while loaded up heaps more and a few carbon A-cats masts breaking each year after capsizes.

But of course I'm not a carbon mast builder and I really like invite a professional carbon mast builder to go publically on record and provide us all with dependable and updated (2007) data. And personally I would like to see the claims being proven in reality by building such a mast and measuring/testing it in real life.

So who is capable of getting Hall spars, Fibrefoam (Scott Anderson), Saarberg, Riba or any other well known carbon mast builder to go on record on this ?

Wouter

Another thing to remember is that the F16 needs a mast with a different profile to the A class for 2 reasons

1, We have to keep it up when the kite is up - thus it must be stronger than an A class mast.
2, As wouter says, we also sail 2 up - thus we need a stiffer mast. (unless you optimise for single handed)

Now, during my investigations on this I can report that you could build a very light mast but it would not be stiff enough to drive the boat properly - it would not break, but it would not be STIFF enough to be the right shape.

Simon,

Do you have data or statements that can be made public with info about the source and/or measurement ?

My data is all covered by confidentially clauses.

I think it to be wise to have collaborated data publicized before a vote on the tipweight rule is held.

Otherwise we just have : "he says ... but she says ... and I think", which will not get us anywhere.

Wouter

Wouter,

I am in the same situation as you. People who build masts (and boats) do not want their commercial data released.

I can say unequivocally that we could use our standard A class profile carbon mast section on an F16 without any fear that it will break under either two up trapezing and/or under spinnaker loadings either one up or two up. Further, with only the “fixed” rigging IE diamonds, diamond wires etc, it would comply with the current “tip weight” rule, and having the section “stiff” is not a problem, quite the reverses. To marry the sail to the carbon section requires cutting much less luff round into the sail to allow for the extreme stiffness of the section. We have our carbon masts built firstly with the priority of strength and under the criteria that if/when the general public sail them they (the mast) will stand up to the absolute abuse that they will be put under, they are not built only to be treated with kid gloves by experienced racers.
The cost is obviously more than for aluminium but the characteristics of the carbon mast would lean me very much in favour of the carbon. After all, in the overall cost of a new cat the extra for a carbon mast is not the major percentage “ball breaker” that many would seem to believe (approx 8% to 9% or there about). It’s a very nice feeling when you ditch a cat and the mast actually floats and standing up the mast when rigging the boat with one arm is a real joy. Breakages are a fact of sailing whether it be masts sails hulls or any other part of the boat so why isolate carbon masts, aren’t all breakages the reason why we have insurance for any way?

Simon,

So why do you want to get rid of the rule that basically provides a minimum weight, hence provides a loose control on minimum stiffness?

On one hand you argue against the tip weight rule because you believe the builders can go lighter, but then you bring up the point that lighter won't be as stiff, hence it will be slower.

Maybe I'm being a bit slow, but I don't understand your reasoning for removing the rule.

I should state that I still don't have a definite opinion on the matter of mast tip weight. There are pros and cons for leaving the rule as is or removing. If anything, I'm leaning towards leaving the rule for the time being, more for stability in the class rules than anything else.

Personally I feel that to have any “rules” that are not entirely necessary just cloud the issue and, as it seems here, create unwanted debate/argument. I feel that the mast tip weight IN practice will and does take care of itself without the need to have it written into the class rules
Any rule that, seems to a lot of people to be ambiguous, often can create dissent from within its membership and has the appearance to the outsider of being a reason to have doubts about the wisdom of becoming part of an association who appear as if they can’t even agree on something that to all intent and purpose appears at the least, insignificant, and as such should be deleted from the rules
If the association DOESN’T want carbon masts then delete the tip weight rule and add, “carbon masts are not allowed” if not, then clean it up and just delete the tip weight rule!
Just my opinion.

I should nave added that when I say “it will take care of itself” I should explain that it is my belief that IF some one did try to take advantage of a “no tip mast weight” and built themselves a mast much under that 6Kg tip weight, they would obviously be flirting with disaster as far as breakages are concerned and if they spent the money to only see it go down the gurgler, they are not going to be to keen to outlay the same money again knowing that their mast will only fail again, and as well, to gain any major advantage from a “light weight” mast they would have to go WELL below that 6kgs to be effective and not by just a small amount. So I can’t see carbon creating a price war within the class, there are already F16’s sailing every race day with carbon masts and the sky hasn’t fallen in yet, and the nature of the appropriate cost and structural limitations of the material will keep the existing status quo regarding the percentage of aluminium to carbon masts for a long, long time to come.

Exactly my point.

Masts can go a little lighter and so allow lighter people to sail the boat, but the minimum weight of the mast (and so tip weight) will be self regulating as the builders cannot build a very light mast that will perform (i.e. not stiff enough).

We currently have a rule that artificially controls the mast tip weight for no real reason.

I can tell you and everybody else that this particular F16 class rule was the one most negociated over !

Don't think for one second that its inclusion was without reasons.

And nobody should assume that absolishing it is without (possibly serious) consequences.

Wouter

OK Wouter, given what has been said that you could not build a stiff enough mast with a tip weight below 5KG (my sources suggest that it might be possible to go to around 4.5KG. Please can you explain why we should not remove this rule.

As far as I understand it the following reasons have been given so far for keeping the rule.

1, Carbon masts would be built too light and so would break. I believe John P and others have refuted this already. In order to build a stiff enough mast, a certain amount of cloth is required, thus a certain weight of mast is inevitible. And from a commercial point of view, it would be insane to build the masts too light and get the reputatation for having fragile masts which did not perform properly (when a stiff mast is required).

2, To allow Alu masts to compete directly with carbon. I would be very interested to hear what the tip weight of a (say) Blade Alu mast is.


Please could you also explain the serious consequences for removing the rule ?



I would really like to understand the reason we have a rule that limits the people who can sail the boat, and force mast makers to make masts heavyier then they need to be (or add correctors).

Afterall, if we have a boat with a lighter mast, more carbon can be added in other places and so make a stronger boat.



I am interested to understand why we have this rule.

Simon,

please don't repeat statements like :



Ad infinitum.

In other posts it has been shown that this statement is unfounded. Tipweight does not limit which people can or can not sail the F16, afterall with righting aids everybody can. A portion of alu masted F16 owners do use additional righting aids and there is no reason why other sailors can't do so as well.

Repeating this statement as if it is an commonly accepted truth is simply not thruthful.


From now onwards I shall be completely honest and it should be noted that this may bring me into conflict with some parties. I trust that this is appreciated.





The initial statement is wrong. The superwind mast is nowhere near as stiff as the Stealth mast I raced with still the two rigs don't seem to differ much in performance at all. Lately I've been dueling with an carbon masted F16 and interestingly enough the difference was not always in favour of carbon. Again I really don't see why mast stiffness is made into such a big issue. And I certainly don't see mast stiffness as a limiting factor for tipweight. As such there is no self governing principle to be found here. Not in the way as you present it.

The data provided (during time of acceptance of tipweight rule) by the only carbon mast builder for F16's till recently was achieving 5.5 kg tipweights on customized 1-up masts. 6.00 kg tipweight was therefor a close approximation of what was reasonable.




The reasons for the current tipweight rule are far more political, economical, organisational and perceptional then technical. It has always been that way.

Some of these reasons may not longer apply but that is a different discussion.

First off.

In the beginning we (as a class) simply could not accept a few mast breakages in a row. Perception wise this would have been a PR disaster. Yes it will be insane to build masts too light but as a class we couldn't risk somebody still being foolish enough to try. The tipweigt rule directly addressed the peer pressure a mast builder could feel to "risk it".

Secondly the F16 concept is intended to use the same hardware both in 1-up and 2-up modes. It is not in the interest of the class to see a specialize 1-up masts that can not be used for 2-up mode. This problem did arise in the Taipan 4.9 class where 2-up crews would buy boats with optimized 1-up masts and break them. It was decided to avoid it. Adding layer of glass or hoops in carbon masts was a way around this issue. With it the bending characteristic of a mast could still be fully optimized without risking breaking it when abuse by a heavy two-up crew. The glass (or hoops) do not add stiffness but do add robustness. The tipweight rule was the best way to achieve this. In the Taipan class the 1-up mast was eventually phased out and replaced by the 2-up mast with an adjust cut for the mainsail.

Thirdly, carbon was expensive back then and carbon masted F16 were far too expensive to start the class up with it. At the time there was a need to keep the boat really affordable or the F16 class would be a dead-born. The only way to achieve that was to use alu masts. And the only way to make sure that Alu masts would be considered competitive was to limits the PERCEIVED benefits of the carbon mast. Again the tipweight rule was the best way to adress this.

Fourthly, it is paramount for the F16 class to have several builders offer fully optimized F16 designs. This makes the class alot more viable and assures interested parties looking to get into F16 sailing. Only Stealth marine at the time seriously considered marketing their boats with carbon masts, all other possible builders were pretty much supporting the total ban on carbon masts for economic and profit reasons. Stealth Marine and the homebuilders were too small a base to succesfully start to F16 class upon. At least a 2nd commericial builder and must desireably a 3rd was needed. The 2nd proved to be VWM and the 3rd is AHPC. When AHPC launches then the F16 class will have been succesfully established and the 4th and 5th builders are then expected to link up. In my mind these are Blade AUS and Bimare. It is my understanding that VWM, AHPC and BLADE AUS are not yet in the position to offer their products with a carbon mast as standard. Only Stealth marine and Bimare can. At this time VWM, AHPC (and soon Blade AUS) are the main stay of the F16 internationally and the best candidates to establish the F16 class in the all important European market. AHPC actually introduced a proposal to ban carbon masts all together. A compromised was reached halve way.

I hate to say but growing the F16 class does indeed include balancing these things. And for the Stealth owners among us, I'm personally looking into raising the importance of the Stealth F16 in the global picture.


5th. Perception of the sailors. This was a big issue back then. A significant group of F16 sailors felt directly threatened by the carbon masts and we couldn't risk the F16 class to be split over this issue. Limiting the PERCEIVED gains that could be had with carbon was the key to solidifying the different parties into a single uniform class.

6th. Interestingly enough a flexible mast is actually better for crews who switch regulary between 2-up and 1-up sailing using the exact same hardware. The Alu mast is considered by some to be superior in this then a carbon mast and I think they are right. This was one reason for not making the alu mast outdated and supporting its continued use in the F16 class. By now the Superwing mast was planned to be replaced by an improved alu design but this project is on hold at this time.


Several of us have sailed/raced against carbon masts and interestingly enough the performance difference on the water is not really conclusive. I personally think that carbon masts have very many PERCEIVED advantages, but many don't really result in much actual gains on the water. So personally on technical aspects the argument can be had that it doesn't matter much either way. The bulders probably no this very well. But this was never the issue that was mostly feared. It is the perception that the customer might has that is most feared by all who are against. And this customer perception can be quite irrational.

If the customer for some reason feels pressured into having a carbon mast then he will demand a carbon mast of the builders, but often not be willing to pay much more for the upgraded boat. 14.500 to 15.000 Euro seems to be the max a EU customer is willing to pay for an F16 whether or not it is fitted with alu or carbon mast. The production cost of a carbon mast for builders like AHPC and VWM is such that offering a carbon mast directly decimates their profit margins making continued production not economic viable anymore. 3rd party carbon mast suppliers are still asking to much for their carbon masts.

I've been involved in actual alu mast production and one can have a die made and run a batch of 30 straight anodised alu masts (discarting a few crooked ones) boxed and shipped for 10.000 Euro's. The same price will only get you 3 to 4 carbon masts by a 3rd party supplier. It is this price difference that allows the builders to make a profit. And this very profit is why they are attracted to design and produce F16 boats. If they have to hand off this profit margin to some 3rd party carbon mast builder then it may be more attractive to leave the class.

Both Stealth Marine and Bimare has in house carbon mast production and as such earn their profit margin either way. This is NOT the case with the other builders. Also Bimare is still not offering a fully optimized F16 and as such we are left with only one builder who can offer a carbon masted F16 at the price the customers are willing to pay. Sadly this builder has the least market penetration internationally to fully support the F16 on its own. So we are stuck with supporting the Alu masted F16 builders to grow the F16 class.

I do really hope to see a several Stealth F16's at the Global Challenge in Zandvoort this Aug as otherwise VWM and AHPC will corner the European market and press the Stealth design out of the mainland market. In my analysis, the builder (or builders) that establish itself (themselfs) as the dominant supplier on the EU market will grow to be the most powerful infuence in F16 class business. The way the carbon mast issue is handled may well be determined by such a development.

It is just a wild idea but would it be possible for Stealth Marine to establish herself as the dominant carbon mast builder for F16's. For years now she is underquoting the 3rd party carbon mast builders like Hall Spars, Saarberg, Fibrefoam, Australian Composites by a big margin. By now Stealth Marine has considerable experience in building these masts. I see a market potential here as other builders don't really care what kind of mast is on their boats as long as their profit margins are garanteed. If Stealth Marine can offer these at 1000 Euro's while another 3rd party builder asks at least 2000 Euro's then ....

Maybe the Italian Riba company can.

It is time for some hard competition driving the carbon mast costs down. Because if it stays at 2000 Euro's for a carbon blank incl. taxes then we'll be sailing with alu masts for a very very long time. With tipweights of about 8 kg.




I gave the details on that in an earlier posting.


To summerize this post. Be very careful with what you do with the tipweight rule. There are some rather powerful forces at play here and it is safe to say that they would vote for a total ban on carbon masts before they would vote for the removal of the tipweight rule.

Opening up this discussion may have a totally unintended outcome.

From my own discussions over the years and what my network of sources is picking up I can assure many that the current tipweight rule has been an excellent tool in keeping a lid on this pandora's box.

The only way to express how deep this issue goes without breaching confidentiallity clauses is to note that I personally will not support any change to the tipweight rule even though on pure technical grounds I no longer see a compelling reason to have it. I would love to have such a light weight carbon mast myself but I don't think it is in the interest of the F16 class to have it.

Wouter

Have we had umpteen broken masts, no, is this because builders are building over stiff masts so they measure to the tip rule ? I’d say not; I’d say mast builders are building masts how they want them and then adding lead to the to to make them measure



Agree that the concept is to sail 1 and 2 up; but the right mast for sailing one up will not be the right mast for sailing 2 up. You comment on optimised one up boats not being good for the class, but there are already 3 single handed optimised boats I can think of. Altered was a solely one up boat, I know of one other Stealth that can Only be sailed in one-up mode and my boat is optimised for sailing one up – I have a single handed cut sail, and all the “2 up kit” can be removed except for 8 bolts that hold the self tacker on. I believe John may have made my mast on the basis of sailing single handed and so my boat will not be a quick sailed 2 up. Optimised single handed F16’s exist.



I can understand this when launching the class.



I can understand builders not wanting to build a carbon mast to start with, but I believe that this will change as ther benefits of the carbon mast are understood. Is there not a Blade with a carbon mast at your Club ?



I and others perceive these gains to be real and so use Carbon masts.



Really, If I was sailing 2 up I would want a STIFFER mast as the loads and Righting moment of the boat are different. Sailing 2 up you would need a stiffer mast to support the increased loads.



Really. I find this surprising. How many races are you basing this on. Do there appear to be conditions where Alu performs better over Carbon(and visa versa), or is there a general equality ?

Just a small comment.

An F-16 class where carbon masts ruled would not have made it very attractive to me. Why? The extra cost for the tube would have been enough for a poor homebuilder to stop the project. This is just me (and my current crew, Frode), but with alu Tornado masts a dozen a dime (almost) an F-18 or F-16 can be buildt at an affordable cost. Frode paid US$250 for a Tornado mast to go on his F-16 just three weeks ago. I paid a similar amount for an old IYE Tornado mast to go on my boat earlier.

I can't deny nor confirm that fact.


Wouter

I can't deny nor confirm that fact.


Wouter

Gee that sounds like a quote straight out of "yes minister"
You could have used the, "You may very well say that, but I can not"
All of which is usually a way of politically saying yes without saying yes?