Yes, I have been looking for an affordable used boat and can't find one, especially considering the extra shipping here to Hawaii.

Who are you? I was in Ann Arbor a couple of weekends ago with a Viper.

(edit)- Also currently in CRAW we have a used Blade, Falcon, and Viper available. I'm not sure the age of the Blade, but the Falcon was new last spring, and the Viper hasn't even hit the US yet, and I can get you a new Viper as well.

Wayne, If you seriously think that the development done on the F20 foils will negate any development costs for a curved foil for an F16 then i'm sorry to tell you this: You have no idea what you are on about!




I can tell you from experience that the cost to build a mold for a curved board is a much more complex process and the costs are a lot higher in all steps, design, billet, cutting time, finishing, and even foil production. If you have a cheaper way then please let me know..




And you base this assumption on your extensive experience with both straight and curved foils?? I can tell you from my time with both foils that there is nothing in current technology that makes as much difference to the performance of a boat that the change from straight to curved foils. If all else is equal (ie sail area and dimensions of the boat etc) then the curved foils make a bigger gain in performance than any other feature.

Well this is not completly thru. We are experimenting a lot with both configurations ( straight and curved ) and to be honest which type will be really quicker we still do not now. It depends a lot on the conditions ( wind , wave ). We do know for sure that in light wind the curved boards are definitly slower then straight boards.

Hans

Hans,

You would be referring to an A Class? There are several issues in using the A class as a basis for foil testing: With the class rules restricting the curvature of the boards and also the fact that the righting moment is reduced with curved boards (A Class is already narrow for its length) plus the fact that the A Class is not adding any sail area downwind. all these factors reduce the impact of the foils in a performance test.

We did many hours testing with identical platforms and changed only the foils. The results were conclusive: Curved foils were always better on a 2 person, 3 sailed boat with a wider ratio to length than an A class.

Yes , i refer to A-class but the curvature of the boards is not restricted, the only restriction is that the tips of the boards when full down not closer is then 1500 mm. There is some room there to play with and there are several different type of curves used at the moment.
I go with you when you are adding a spin on the boat , in the F16 you may have canted boards ( 6 degrees )and in certain conditions with the spi flying this is helping the stabilty of the boat. I am not sure if the curved board will work on a F16 ( i am going to try that one day ) because the boat is relative short and that is maybe a disadvantage.

The shorter the boat, the better foils should work, it would need some thinking out of the box as to correct placement as upwind and downwind would be two quite different issues, I think there was a Dutch development 20ft boat a few years ago that tried a 4 board system with straight boards, perhaps if they were to repeat that with the knowledge learnt from curved boards, they may get interesting results.

Macca it is too bad you have "pissed in the sandbox" so many times...On this occasion you actually have something of substance to say... some interesting inside insight into curved boards design as done by NACRA, unfortunately few appear to want to listen to you based on your past pointless pot stirring...too bad...I think there are some golden nuggets that could be gleamed from your experience on this particular subject.

Didn't any of your marketing professors tell you..."Its not what you say that people remember...but how you made them feel"

waynemarlow....interesting you mentioned the four board system...I was thinking of that myself...it seems like it could be the next natural progression of the curved boards...a forward and rear board that could be raised and lowered to dial in the proper lift and for/aft balance could be an interesting experiment...might think of the single foil of the current boats as being similar in principal to a unicycle and a two board boat (per hull) similar to a bicycle...

Instead of doing a "wheelie" it might translate that power into forward thrust...of course if the front foil loses lift and the rear stays hooked up...wow...talk about a neck breaking catapult...LOL

No matter what foils you put on, straight put on at an angle or curved with or without twist the thing I don't get is how do you control the foiling (even if it is only partial foiling).

It seems to me you need a way to dynamically control the stance of the boat to avoid the F20 carbon "jump", or the "dive dive dive" if by mistake you start to pitchpole. I understand that weight placement and how far you put the board down will help but it will never be as reactive as the combination throttle tiller/active wand of the moth, the trifoiler palpers or the self regulating foils from the hydroptere/white dragon.

IMHO the next chapter in multihull foiling is not in curved boards, it's on how you control them. The more speed you have, the less angle you need, so as you accelerate something has to change somewhere to keep the lift under control.

Anyway, I'm not even sure why this discussion is in the F16 forum: F16 rules prohibit foiling in multiple way so if you want a foil fix hit the gym first then get yourself a moth or a rs600 (foiling on the wire!).

Wayne, I am seriously not trying to pick on you here but the dutch boat you speak of was actually a boat co-developed with Rob White. It had the 4 boards and it never worked... In fact the guy who drove the entire project has recently sold the boat and bought something else..... GUESS WHAT

The F20 never foils as such, its not designed to do that, the C boards are there to give a minimum lift to slightly reduce wetted surface area of the hull, that minimum lift clearly can be seen when in the video with the rear down to give max angle of attack, the boat raises only a few centimetres and then when the angle of attack becomes too much, the boat settles down in the water. Note how much speed was lost from the very draggy foil at max angle of attack.

There has been some discussion within the A's as to its merits and failures and in what conditions they do work. As much as Macca states the A is not comparable, sorry but the boat speeds are not unsimilar and that is what produces the lift regardless of how much horsepower you throw at getting that speed.

This boats speed is probably as much from modern hull design learnt from the Americas cup as from its C boards, the boards are simply not big enough to foil and the boat too heavy to allow true foiling.

As with all things though there is a down side to foils ( as per the foiling C Cat experiment ), the C boards will magnify and slow the boat through additional drag as soon as they are not in optimum AOA and my guess it will be slower in the lessor sailors hands than one with simple straight boards as they will not have the experiance to know how to balance the boat as well as the pros can.

Scaling the NACRA 20CF down to 6-6" between daggerboards...or centered on an A cat with 12" wide hulls, would bring the daggerboards within Aprox 1220mm of each other tip to tip(or close to it) I have to give that one to macca...
You wouldn't be class legal

Wayne, thanks for your opinion. Here is another point of view from a guy who has some experience with the issue. (from the daily sail)

"However Coutts does believe that foil development will be significantly more important than it has been in previous monohull Cups for it seems extremely likely that at speed the foils will be lifting the leeward hull out of the water, partially or completely, to reduce drag. Among the large trimarans competing in the Route du Rhum the difference between having lifting foils and not having them is said to translate to around 4 knots of boat speed..."

You can argue however you like, but the simple facts are that the curved foils are a clear advantage over straight or canted straight foils.

I have sailed A cats with and without curved boards, and to be honest my feeling is that there isn't such a clear advantage with the curved boards. I think this is due to the A cat being more about efficiency and drag reduction rather than dealing with excess horsepower like you have on the F20 and the ORMA 60's etc. Its a very different style of boat and as such the requirements are different.

Yeah, he certainly will be in any discussion I have about Nacra with someone who doesn't know any better. especially when it comes to someone ever wanting to buy a supposed nacra f16 if one ever comes. Nothing like a company crapping on a class that they want to sell boats to. Seems odd that people are getting on the F16's sailor's cases for chiming in on the main forum. A factory rep from a company that doesn't make an F16 repeatedly crapping on the F16 class. Not one of the guys on the main forum would put up with that either.

BTW macca, can I quote you that the boards for the F20C will be 120% of an infusion board? so, Murray's price is 450$ which would make the F20C board 540$. I think that is actually reasonable, though I doubt this will be the case.

Me too, not much more than an AHPC board.

mecca aside...it is funny how we all want to be paid well for the work we do, but everyone else is supposed to work for free...like it is insulting for any boat builders to actually expect to make a profit for their effort. How many people go to their job expecting to break even at the end of the day?

own your own company? I'm happy if I break even at the end of the day. Ecstatic if I make money.

I certainly don't expect people to work for free, although I have to about 20% of the time. and this is likely to go up.
I don't expect nacra to work for free... just "truth in advertising" is necessary. besides, it is macca representing nacra. He needs to realize who is the customer. It is us, so why would he always piss us off? because he doesn't know what the hell he is doing. Yes, a good sailor, but not a good salesman.

PTP, if you are pissed off by me informing a forum about the costs and complexities of building such foils then its going to be pretty hard to make you happy... So, how about you tell me how to make you happy?