2nd attempt

they were doing about 18-22 knots upwind and waterline length was between 110-130 feet. 1.34 * sqrt(110) = 14.1 knots. so like I said, beyond "hullspeed", ie. most definitely going faster than a wave of the same length as their hull. at some point, adding length for a given power will just add drag through skin friction.

Michell's slender body method works well for slender hulls, but these beasts may be out of the traditional bounds of applicability for the maths. even moths fall outside the range. ie. they are too narrow for what has been verified with this method. not to say it isn't accurate, just that it hasn't been tested and proven to be accurate. although that could've changed since I last read up on it.

sys F16 doesn't appear to have a bridle network with diagonal beams under the tramp, infact they say it is striker-less.

yes sys doesnt have a system under the beams al la Alinghi.. But the kite tube and pole is the system it appears..

I came into the class after the bannana board debate. Anyone care to offer a synopsis? I don't want to reopen the debate, just trying to understand the rationale.

*bites my tongue*

That they are not allowed or theory behind their function?

Both if we can do it without burning our house down. But, judging from Stewart's reaction, I'm almost afraid to ask.

Insure your house then ask again at the closed forums.

Why be scared of discussing legitimate issues????

My PERSONAL 2 cents worth:

Bananaboards would be a very interesting development on an F16. This would be especially true if coupled with T or L foil rudders. Apart from not being allowed under the rules, the time is probably not right for such a development since the class would, in all likelihood, implode if a bannanaboard boat proved ultra fast or ultra competitive. I firmly believe there is a bright future for innovation, development and experimentation within the rules as they currently stand - without introducing a potentially expensive and damaging (in class growth terms) complication such as bananaboards.

I'd love to see the rules opened up in the future to permit experimentation with curved boards (and other freedoms) but I'm talking at least 5 years or even 10 years on.

Of course, outside of class racing or the F16 banner there's nothing to stop people experimenting - but to protect the growth of the class by providing some stability, bananaboards must of necessity be banned.

Don't forget, the current ban was the result of a class wide ballot back in 2007 before the current rules were finalised.

Once again, this is my personal view, it's perfectly possible that the F16 Governing Council may decide in the future to ballot for such developments to be permitted during one of the constitutionally permitted 5 year reviews of the rules.

Hold on. It's straight forward! At least in a layman's view and should not require any flame suits.

F16 is not an "arms race" class but yet is not a "stagnant" class either. Curved boards are still the extreme and cutting edge for beachcats. You will have an extreme gap of the "Have" and "Have Nots". Incremental changes within the box rule are OK; ie. moving back the forward beam and moving foward & lower volume. Or main sail cut.

According to the commentary on ESPN360, the concept of curved boards have been around for a while. Their function is to lift hulls. For example; A-Cats are carrying less volume/ft than the F16s (especially the newer F16s) and are more true to the wave piercing concept. They are more likely to benefit from curved boards. Whereas, the Viper and Falcons are proving to hydroplane very quickly "as is" and anymore lift may make them less stable at speed, especially with a shorter LWL.

The F16 box rule does have a compromise? It allows for a nominal amount of fixed cant in the dagger well?

I would think that the difference in cost to build a boat with curved rather than straight boards would be less than the increase in cost to build it with carbon beams, mast and hulls as the current class rules allow...

I was just thinking that storing curved daggerboards would be a pain in the rear.

But man are they cool looking. Performance enhancing or not, I don't care. To me they're like boobs. They could be totally useless, (minus the nursing), but I love them.

Carbon is cheaper than Alu extrusions in some parts of the world.

The point is though Andrew that switching to carbon extrusions won't give any major change in performance whereas a change of foil format could (possibly a vast change). As Kris has pointed out this would create the 'haves' and the 'have nots' and that is NOT GOOD.

Having some all or part carbon boats might make a slight difference but is unlikely to create an arms race as the greatest variable and effect on performance will still be the sailor on the tiller.

Can you give me the contact details? I would love to get a couple of hundred carbon beams made up...

Talk to Rolf; he is making Carbon beams becasue they are cheaper than buying in alu extrusions and fitting them out in Norway.

This situation only arises in places where the metal-guy charges astronomical prices to import a very small number of simple alu extrusions and the buyer himself is able to produce his own carbon beams (negating labour costs).

I have never seen a situation where the production of commerically available carbon beams is cheaper or even just as expensive as extrusion of high grade alu beams. In fact I don't believe we will ever see that happen at all, especially not when ordering more then 50 sets in one go (500 kg combined).

For those production batches, extruded alu beams of the 6005 T5 variant are incredibally cheap. The same applies to alu masts.

I'm not allowed to say how cheap exactly but trust me on this, carbon will never win over alu in that area. And I'm not talking about alu being cheaper by factor of 2, 3, 4, 5, ..., ..., ... either.

It is just one of those freak occurences when you live in some far of place without a sizeable industrial base of along an international shipping route.

Wouter

[quote=Wouter]
I'm not allowed to say how cheap exactly but trust me on this, ....quote]

I can... 500kg of extrusions should cost about AUS$3500-4000 or $70-80 per boat (assuming Wouter's 50). You'll pay a premium beyond that depending on the tolerances you demand. The premium is based upon wastage and also how often the die will need to be replaced.

Anyone want to source a PAIR of carbon beams for that price ?

Wouter

I wonder why Rolf didn't just order a set of beams from a current manufacturer....