Front Beam

Do we need a dolphin striker?

On a Viper with Ali beams? Yes

Alternately there is only one way to find out for sure....

I mean rules wise. Is it required?

From the top of my head: A dolphin striker is not required in the rules.

Materials in the beams are not restricted either.


Class rules are missing on the class website so it is impossible to check if there have been any changes on this over time.

I didn't think so, or at least I didn't remember seeing anything about it. I knew materials weren't limited. A carbon front beam could be designed to not have a dolphin striker, whether or not there is a savings in weight I don't know. It could certainly be stiffer.

No dolphin striker to hit waves is faster.

I dont know what happened to the rules in 2010 as the ISAFisation process was going on.. Look at this for the rudders in a PDF of the 2010 rules I found on the forum on the class website.




Now what does this mean?? Rudder winglets certainly is allowed in multiplie configuration and is used in the class but this effectively does not allow L-shaped winglets. No discussion, no ballot and comments..

T foil rudders are specifically mentioned as allowed. No varying shape is allowed on the dagger although they could be assym as long as they are straight and canted no more than 6 degrees. You could easily argue that a J or L foil on the rudder would be likewise allowed.
What is not mentioned is moving flaps or likewise appendages. By the rules you could add them on the rudders now and vertical flaps to the daggers too if you wanted to. - That ought to bring forth a big rules debate as soon as somebody shows up to a worlds sporting moveable flaps.

Does anyone have a link to the current rules set?

Was there a class meeting at Racine?

Which after this AC and little AC cycle is a total reality

I think the hulls as we have known them are going away and the boat will become a ladder frame to attach sponsons and foils.

I was unwilling pay the collectors price for the Bernard Smith book, but iirc he talks about fat foils which lead to limitless design possibilites.

Mirabaud already went that route. It is not fast when not foiling

This might be a good thing for the class if it can be done well, and still be usable for single handing, and not add a lot of hassle to sailing off the beach. I for one would be pretty likely to switch to a full flying F16, as we're in the ball park weight range and have an existing local fleet. Trouble is the existing boats are not good in short chop on a distance course where waterline is king. Full flying changes all of that.

No foiling in the F16 class as the daggerboards can not go more than 6deg off vertical. This makes it hard to get enough surface producing vertical lift in the water.

Sensible approach in my opinion. It is still early days for foiling. What would be cool was if somebody starter testing foiling under the platform outside class racing.

The early Stealths did not have a front Dolphin striker and had T Foils way back in 2001, very stiff boat reliant on an oversize extrusion designed for the Dart 18's. It was only when John couldn't source the beams any longer did he change to a conventional set up.

As to foiling, nah we are just too heavy, but a semi foiling mode maybe the answer. Interestingly the SCHRS handicap system will defeat most foiling boats ability to really shine. Type in your boats details and then try the same with the lifting boards tick box activated. Watch that handicap get real tough. It amounts to a penalty of about 20 kilos of ballast. Mmmm

I would love to see some of the A Cat guys build an arched front beam with no dolphin striker. Are there any out there already?

It would have to be made of carbon of course, unless you're really good at custom bending alum. tubes.

I guess you could put on a huge oversized straight tube, either alum. or carbon, with a thick enough wall, it wouldn't need a striker for support, but it'd be heavier and more drag when you do hit the top of a wave with the beam.

I have not seen arched front beams on A-cats. More surface area to contend with in the build.

The C-cats do have curved beams, but with dolphin strikers from what I remember.

Bending an alu tube of 80-100mm diam would not be possible I think without compromising the structural integrity.

Hydro's has a dolphin striker (here: http://4.bp.blogspot.com/-plJNEqIu7...k3vAWmg0/s1600/cclasshydrosADimages1.jpg)

That doesn't mean the other boats do. The DNA does not have a dolphin striker, meaning you can probably do the same on a F16. That is the kicker with the F16 rules as currently written, as has long been discussed elsewhere.

Phantom built a foiling F18, but in carbon of course. Reading between the lines the existing hull shapes are fine but longer and wider is much better, as is having a second pair of hands to work the dagger boards. Time will tell.

The early F18 used the beams from the 20 foot 10 foot wide Tornado because it was easy to source and that became the standard. Some of the builders are using this same oversized beam now on their F16. Both are overkill and it would be a simple calculation to see if they would be structurally capable of handling the loads without a striker.

If they could it would likely be a bit more flexy. I heard a rumor where Ashby installed a striker on his A class “stikerless beam” anyway because he thought the increased stiffness outweighed the added windage and weight.

The C class have a square truss system built into their designs. This requires the stiker post and its runners to each corner of the platform. They then can have a very light beam set as the truss system, which works off the striker and the standing rigg working together, provides all the structural stiffness at a significantly lower weight penalty than having big overbuilt beams. Looking at the AC45 and 72 they are doing the same thing it appears to me.

I've been told a striker and beam on an A wieghs less than a striker less beam. A triangle is a fantastic way to add strength.

Efficiently reaching your goal. You do not think the AC and C class guys would place those very complicated strut systems on their rides if is was not more efficent.(better)

You are right on the C class and AC72s.
The F16s do have a minimum weight in the class rules so building a strikerless mainbeam might make sense if there is an available weight and money ration on the budget

Rolf, You mean increase the striker and get rid of (reduce) the cumbersome beams. The big builders felt they could jump on the marketing potentail of the F16 class and convince everyone they had to have beams and things designed for 20 foot boats. Of course this is good for the builders because they do not have to design anything, but now a big part of the class sails around with a ton of extra weight.

If strikerless was better, they guys investing money on speed in the true developmental classes, would obviously be working to go that rout

Good history lesson on the original beams...explains why our F18's are such pigs.

The top A-Cat in the world right now is arguably the DNA. It does not have a striker on the beam! When you go to a C-cat, AC45, AC72 etc. the loads are much higher than on the smaller boats, the structure is physically much larger and yes a triangle striker will be lighter.

I suspect there is enough weight budget in the F16 class rules that a carbon front beam can be made to work and this is more aerodynamic than the triangle beam, plus better from a wave slapping standpoint. This of course is more costly. That is why IMO the F16 class needs to tighten down the class rules and follow the F18 lead in some ways on this issue as you continue to build fleets-no one wants an all-carbon F16 class killer.

The A class has significantly lower loads than a 2 up spin rigged F16. It is also narrower so making a strikerless beam is a more reasonable solution to their design tradeoffs. The DNA chose this path and have a fast design. Would the boat be even faster or stiffer mounted with a striker?

There is a minimum weight for the class. They cannot go below this, so a lighter striker system does not buy any weight advantage as it does in the larger designs you mention. They chose a build process that used more carbon but fewer pieces and the sales pitch for lower windage etc. For this boat probably a wash both cost wise and performance wise.

There is a min weight for the F16 class as well. There are also already minimum or very nearly minimum weight platforms out there made from standard laminates. There are also various degrees of carbon to full carbon boats out there. The class is continuing to grow and the existence of these boats has in no way brought about the death of the class. Allowing options is an attraction for many. This doom and gloom prophesizing is getting a bit worn out. The DNA did not kill the A class nor did the Flyer or the first of the 75 kg generation like the Jav. All those boats seem to have increased participation not killed it. The F18 class has been very successful and I wish them continued success as it is good for multihulls, but the class is not for everyone. Just a quick view of the infighting and continued arguments over materials and rules minutia is more than enough to drive me from considering an F18, nevermind having to pay that kind of money for an overweight out of date vessel.

I'm not predicting doom and gloom for the class. I know if I was buying a new boat and a full carbon F16 was a possibility I might very well take it. By the same token, you cannot argue that a minimum weight carbon masted, carbon hulled F16 isn't going to be faster than a vinylester boat; maybe not when both are brand new but give each a year of hard sailing and I know what I would pick. The main reason I'm not on a F16 right now is the F18 is a better distance race platform, there is much more competition globally, and I already whack my helm in the face with my elbows on the F18 tramp, I know I'd be sent swimming for shore on the F16.

I also agree some of the rules in the F18 class are a bit excessive. For example, I think epoxy should be a valid material, and the sails should have open materials; both of these add very little cost, if any, to the build of a boat and increase the longevity of hulls and sails. However, calling the boat out of date is a very huge stretch; all your F16 sail and hull shape developments have been a trickle down of the design efforts placed on the F18's.

Well Sam,

you also ask Gøran Marstrøm to build you an F16 in carbon, bake it in an autoclave and fit it out to his spec. Would it make the boat faster? Perhaps theoretically, but in real life.. I dont think so.

Nice thing about F16, if you want a full on carbon version you can get it and still race. Nobody is going to bitch at you becuase you have a sticker on your sail that is made with a material that is not approved.

Have you ever put a tape measure on a tramp of the various boats? There is only a 2" difference in platform width between the models and the hulls are fatter on the 18 so in actuality the hull centerlines fall in almsot exactly the same width and the trampoline itself is actually wider on the F16 than the 18. Inside on the beams is only 2" shorter. (as just measured on my Falcon - other models may vary)

As for trickle down The only thing the F16 took from the 18 is the rigging layout for a spin rigged boat. With this the F18 class did a lot of work and came up with some pretty good useable solutions. Hull shapes, sail shapes etc all came from A class (except for spins, and there both the 18 and 16 classes were following the T)

If you want to talk materials weight and performance, get Matt at Falcon to chime in. They regularly produce boats with a bunch of material choices. What other builderor even boat design has identical rigged and molded platforms where you can look head to head at full carbon versus, Kevlar, S-glass, fiberglass different resins, different cores, carbon masts, aluminum masts etc. There are some real world comparisons there, not internet hype.

Keep telling yourself otherwise, but a full carbon-epoxy boat will outlast the glass equivalent. Performance wise? It probably doesn't matter straight out of the box. As far as F16 vs. F18, everyone has their choice for a reason. I think the F16 is a great boat, but here in the real-world the F16 will pitch pole first, is slower through short chop, and has yet to show us better performance in light air, so I'll continue sailing our overweight F18. Where the F16 really shines is in the versatility (sort of, 2-up is faster), and getting it up the ramp at the end of the day. As to size, we feel cramped on the Blade. Will give a Falcon or Viper a go and see what we think, but the hulls are MUCH smaller than the Infusion hulls so again, we are more forgiving to drive and faster when the wave state builds. Plus we are a little heavy for the F16, at 310lbs dry. Finally, we have an America's championship regatta with teams flying in from Europe and South America to compete against, plus Catacup, plus a highly competitive NE fleet. We are learning a lot at a very rapid pace in the F18 and I just don't think it's possible in the F16 right now in North America.

All of this wasn't my point to begin with in this thread; my point was a striker less beam can be built, total platform weight can be kept to class rules minimums, and a stiffer platform can be achieved (UHM carbon is MUCH stiffer than aluminum). Would a carbon striker on a carbon beam be the stiffest solution at the least weight? Absolutely. But that wasn't the question. Strikerless can be done.

Good old cost vs benefit equation seems to still be working Sam.

Striker less F16's are pretty old hand when you consider the first Stealths back in 2001 had no striker but a Dart 18 extruded beam, it was only when they went to 2.5 m wide did they go the conventional route. Having owned both there was no real difference in the way the boats felt.

From real life experience there is not much difference between glass and carbon at the min weight we have to weigh in it. Yes carbon may feel different but with good manufacturing techniques and small key strengthening areas in carbon, will be almost as good, that after all is why the weight is set at 107kgs.

This weight / carbon thingies has been debated ad nauseom over the years but the heaviest weight all glass boat using F18 beams and ancillaries made by a certain Aus manufacturer seems to still win the F16 worlds year on year. One could say that the best most trained sailors will always win.

uhhh, that's not going to sell a bunch of new boats now, is it?

And that has always been one of the archilies heels of the f16 class, people bought new boats as early adopters of the class but 5 years on have invested only in new sails to remain competitive due to there being no new leap in designs within the class. Why spend a load of dosh when you don't need to remain competitive.

But with no one selling boats because there is no leap in design, there are few boats on the market for those who want enter the class at a discount unlike the F18 class and A classes where a few year old, now superseded design, can be bought at a huge discount.

So to enter the class you need to buy a new boat and few are willing to dip there toes in the water at a premium price. The class rules were ahead of there time but by setting good weight and build standards the consequence has been slow growth.

Wayne,

I think the issue is with the class itself. You don't have the ultra competitive sailors flipping boats every 2 years, and I think this is going to slow down in the F18's as well. We're on a 5 year old F18 and have placed in the top half of the fleet at most of the events we've attended. There hasn't been a major F18 launch since the Infusion/C2 either. An 07' Infusion was in the top 10 at F18 Worlds.

Anyway, the crux of the matter is new boat prices aren't getting cheaper and the folks' spare income levels aren't growing to match new boat inflation prices. Building larger fleets in any class is getting tougher; best start by getting your local bankers out on the boats, maybe they'll get hooked.

Are these sailors still in the F18 fleet, or are they starting to move to some other platform/fleet?

Umm, what fleet would you switch to? Some are running parallel campaigns in Nacra 17's, but none have sold their F18's to do so AFAIK.

The F16 is a great boat for its intended use, mixed teams, lighter sailors and those that like to single hand. When you start bumping up near the weight range of the F18, it's IMO a more competitive platform; more boats, more competitive sailors and more regattas.