It is time to end the window in which proposals for modification or amendment of the Formula 16 class rules can be entered.

It seems that we are all very happy with current class rules setup and I must say that I largely agree with that. There is however one point that I would like to make more work off.

Either removing the mast tip weight rule completely or reducing its tip weight limit.

Truth be said and I ask for pardon with the parties who still feel for the current rule.


Reasons for it :

-1- The current tipweight appears not to serve the purpose it was intended to serve. The Superwing Alu masts appear not to have a noticeable disadvantage relative to carbon mast in the way of moment of enertia's.

-2- The current tipweight appears to be too high for modern carbon masts. I was asked by a carbon mast maker to lower the tip weight to a more reasonable weight. Two homebuilder builders have indicated that they had to add to much weight to the mast to get it up to F16 compliance, thus completely losing the optimal feel of the masts. It serves no purpose to hit carbon masts this hard.

-3- It seems to go against the spirit of the F16 rules to have this rule in the first place and then set it at the value at which it is now. I have no serious ground on which to base the assumption that a lower tipweight or even the full deletion of the rule would result in an unfair performance gain. Many people believe that an unfair advantage is present but the numbers simply don't support it to that extend.

-4- The F16 class kept its side of the negociations of late 2002, but a significant part of the other side simply disappeared after having campaigned for the inclusion of the rule. The rule was intended to make way for their inclusion in the F16 at a garanteed competitive level. There inclusion has been, well, remarkably uninspiring.

-5- With the introduction of the Tornado Carbon mast and the introduction of the Nacra I17R (F17) with carbon mast to Europe it will be wise that the F16 allows some extra flexibility with regard to carbon masts. We need to retain our attractiveness to these boats. It will also improve our standing to A-cat designs.

-6- It is quite possible that carbon masts are going to drop in price. Of course Stealth is already offering these at much lower prices than the competition and there are signs that other suppliers are going to surface that will do so too. The price of carbon is close to that of other fibres so that is not an issue anymore. Currently we can buy a full carbon hull cheaper than we can buy a carbon mast, this is weird to say the least. The well known names in carbon mast land do make excellent masts but also ask astronomical prices for them. There is movement in this field and I hope the F16 class will ride this way as a frontrunner in this.

-7- It could never be said at the time but a least halve of the reasons to include the tipweight rule was political of nature. The political nature of the situation has changed and it appears that the only effect of the rule was to make the F16 rules less optimal than we wished them to be.



I ran some numbers on the current situation and this is what came up :

AHPC Superwing (Taipan and Blade designs) tipweight = 100 %
F18 Typical tipweight (2 kg /mtr mast sections) = 121 %
F16 Current min tipweight (1.33 kg/mtr mast section) = 86 %
A-cat tip weight (0.9 kg /mtr mast section) = 63 %
Possible new F16 tipweight (1.1 kg .mtr mast section) = 73 %


However when we start looking at the bigger picture things start to change. Lets include the mastfittings and sails into comparison :

AHPC Superwing rig enertia = 100 %
F18 rig enertia = 134 %
F16 Current min rig enertia = 91 %
A-cat rig enertia = 83 %
Possible new F16 rig enertia = 82 %


Notice how we can get a more robustly constructed F16 mast to approximate the A-cat mast in the numbers ? This is despite the heavier F16 fittings and the heavier sails. The convergence is complete the result of the shorter mast length of the F16's. Mastlength is just such a dominant factor in these relations; weight per length isn't really.

However the picture improofs even more when we start looking at the full picture. With respect to dive recovery and oscillation the ratio between rig and platform is important. Think of it like this. All inertia in the rig is negative as that will exceggerate the dives and oscillation, but all enertia in the platform is good (positive) as that acts as a stable foot which increasing keeps the rig under control and limits diving and oscillations. It also allows the hull to punch better through the wave, BUT this is not of interest here. So lets look at the ratio's between rig and platforms


AHPC Superwing rig enertia = 100 % (double handed)
F18 rig enertia = 100 %
F16 Current min rig enertia = 91 %
Possible new F16 rig enertia = 82 %

So in doublehanded mode even the Superwing alu F16 rig is at least as good as the F18's. And the carbon masted rigs have come closer to the Superwing rig.


F16 solo Superwing = 100 %
A-cat rig enertia = 80 %
F16 current min = 91 %
F16 new rig = 82 %

In the solo case we have a very reasonably shot at being just as good as the A-cats which is very good indeed. The Superwing rig is only 18 % away. Now this may sound like alot but its translation in performance seems to be very small indeed.

I have personally sailed the Taipan F16 in different conditions during 2004 and I can honestly say that the platform doesn't seem to have any dive tendency at all. Nor did I at all feel like the rig was oscillation any more than the bare minimum. Since this summer I'm convinced that the superwing rig (alu) is already so lightweight that any gains linked to even less weight are all but neglectable. Afterall, how can a rig move about (or dive) even less than hardly at all ?

Lets not forget that Marstroms new Tornado Carbon mast with carbon spreaders and carbon this-n-that comes in at 15.5 kg overall weight. The AHPC aluminium superwing rigged mast comes in at 15.5 kg as well ! So who are we kidding here ? We are not talking about 20 kg FX-one rigged alu masts that are accidently of the same length as the F16 masts. Nor are we talking about 10 kg A-cat masts. What we are looking at are 15.5 kg Superwing alu masts or realistic 12.5 kg F16 carbon masts (5.5 kg tipweight). As you can see the alu and carbon rigs are already very close together in the F16 class, much closer than for example the I-17 alu and I-17R carbon rigs are. Actually a F16 sailor helped a I-17R sailor with raising his mast once and thought that hit Alu Taipan mast felt lighter. Considering that Marstroms Tornado mast of comparable length as the I-17R mast is only of the same weight as the Superwing rig makes this claim the more believable.

In short the Superwing rig is already at a advantage to its competition and already behave in such an optimal way that I truly think that any F16 carbon rig will be very hard to recognise as different let alone better beyond neglectable.

However, we're not done yet.

Because the above numbers give a better picture but I believe that there are addition comments that may proof to be the more important ones.

We all think carbon masts to be much better than alumimium and refer to the blistering performance of the A-cats as proof. The question is however how much of this obvious difference is related to the choice of material ?

We know for example how the wing masted Capricorn F18 made an impression on the other F18 still using teardrop shaped masts. When we look more closely we can also see that how all carbon masts are ALSO wingmast designs. There are non teardrop shaped carbon masts except for maybe the I-17R's. More and more I'm beginning to believe that the largest portion of the gains come from the wingmast crossection shape and less so from the choice of material. My own experiences with the Superwing rig last year have completely underlined this. The way the wingmast design behaves is key and that can be had in both alu and carbon.

Then we are still left with one more comparison. Both sailors and windsurfers claim that under certain conditions the carbon masts have better gust response. Quicker gust response. Carbon has a better weight to stiffness ratio than aluminum. This sounds very logical to me. Quicker to bend off in the beginning of the gust and quick to spring back at the end of the gust. However how much do F16's gain by this ? Or how badly are they affected by it.

Lets compare it to the A-cats.

Their masts are about 20 % longer above the hounds than F16's leading to rougly 72 % more enertia of the top. Their weight per mtr. is about 60 %. Their enertia is about 172 % * 60 % = 103.2 % = 103 % as that of the F16's. And carbon fibre laminate and alu have about the same stiffness coefficients of 75-80 GPa. Although it must be said that carbon laminate can be upgraded to 125 GPa (50 % more then alu), however nobody sails with the carbon equavalent of the stiffness of a telegraph pole. It is starting to become clear how close the two actually are, Must closer than simple enertia numbers of the mast suggest. The Superwing mast looks already to have equal enertia to stiffness ratio as a carbon A-cat mast. But the enertias of the tops are the same meaning that in the start of the gust both the alu superwing and the carbon A-cat mast drop away just as quickly. The carbon mast may still spring back quicker after the gust, but this is of importance because now that the enertia's of the tops are about the same the crossection of the alu mast can be entlarged to arrive at the stiffness that gives the alu mast exactly the same ratio of enertia to stiffness as any carbon a-cat mast. How can this be, simple answer really. A-cat masts are significantly longer and the 3rd order relationship impacts heavily on that. So yes alu A-cat mast will be inferiour to their carbon counterparts but shorter alu mast may well be not. Sure more luff length is a advangate in itself but as the as the F16 masts are limited in length the end result is that an Alu F16 mast can be made to closely mirror the gust response that is achieved on A-cats mast where higher technology is needed to do so..

This seems to be the theme with the F16;s. By going smaller we can achieve specs while using less high flying technology. Again I refer to the Tornado carbon mast of 15.5 kg and the F16 alu mast of 15.5 kg. Of course we all know that F16's weight in at 107 kg while the M20 weights in at 120 kg's (Texel measurement). Sure M20 is a more refined boat and much cooler because of its extensive use of high tech BUT I will feel no difference in lifting both masts and I'll still that driving the F16 over the sand takes less effort. When we compare the amount with which the hulls move relative to eachother the F16 wins again. It is often forgotten but dimension are very much part of designing an optimal boat as well.

So what is the point. Simple, there is nobody that claims that A-cats have an issue in dive recovery or oscillation and gustresponses of their carbon rigs. So why would we expect such things of the alu rigs of F16's when the numbers suggest we are close to comparable ? I think both designs are right up their near the point wether enough is enough. Sure we can get even BETTER results with F16 carbon masts but again how much gain can you expect when the basic version has no issues at all in these departments ?

I goes to far to get into the real detail here, but I serious expect the carbon masted F16's to be way more cool but not noticeably faster than the alu rigs. At least not enough to retain the mast tip rule.

There is still the reason of seaworthyness. I still see a real argument to prevent disposable masts or designs that are too lightly constructed and fail giving F16 a bad name as a whole.

Pieter saarberg once expressed he could build a good dependable F16 mast for 1.1 kg per meter. This is 200 grams per meter more than A-cat masts. If we run the numbers on that than we end up with a tipweight of 5.5 kg's ; 1 kg less than the current limit and 1 kg more than the modern A-cat rigs. And the numbers suggest we'll have an extremely good mast then.

I hope you forgive me for this post being a little bit poorly structured but I simply don't have the time to spend more effort on it.

I'm looking forward to your reactions.

Wouter