Foiling for less than a gogillion

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Oct 30, 2011
542
klidescope 30t norfolk
Foil

When will they sell a foil upgrade for our existing boats I got a wing keel and want to recut it to act as foil and lift up for some of that speed
 
Aug 20, 2010
1,399
Oday 27 Oak Orchard
I was thinking our heavier monohulls might be more like the Moth class. At $25,000 give or take for a Flying Phantom I am interested in hacking up a Hobie and giving this a try.
 

Joe

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Jun 1, 2004
8,169
Catalina 27 Mission Bay, San Diego
These foiling boats are all made of carbon fiber.... way, way lighter that your typical older beach cats.... on my old Nacra 5.2, one new replacement dagger board will run you about $450(gel covered foam core). For boats with carbon fiber parts, such as the Inter 20, a single carbon fiber dagger board is well over $700 to replace.

In addition, if you study the design features of the boat in the video, you'll note that the mechanism that controls the foils is more sophisticated than the bungee tension system used on most beach cat dagger boards.

Regarding converting a Hobie.... you would need one that was already set up for daggerboards.... such as the Hobie 18.... but it will probably still be too heavy.

What I would look for is a current generation boat with the lighter weight carbon fiber hulls or even a recent model Inter. If you view some of the videos related to yours there are some interesting postings.... one is an A cat (single sail, single handed) that has been equipped with lifting foils.

So.... I guess what I'm suggesting is that just changing out the dagger boards for lifting foils is just part of the equation to get your boat flying..... a big sail plan on a lightweight boat, a system to support the boat on the foil once it gets airborne and, of course, the bank account and technical ability to develop the right foil for the chosen boat.

A bit daunting, but not impossible, because you have proof that others have been somewhat successful at it already.... albeit not on a Hobie 16.... yet.

Regarding the conversion on a displacement monohull.......uh... it seems likely that you would need a boat that could get up on plane for the lifting foil to perform..... that's why you see them on multi hulls or lightweight dinghies such as the Moth.... rather than a Catalina 30.

Finally, the $25k price tag for the Flying Phantom I seems reasonable, considering the technology..... the real question is does one have the skills needed to sail this boat? I encourage everyone to take a look at the Nacra 17 videos.... this is the new Olympic mixed multihull class. http://www.nacra17class.com/
 
Aug 27, 2011
408
Catalina 27 Titusville, FL
I think you can foil a heavier boat like a Hobie 18, you will just need bigger foils and you probably won't go quite as fast.

Just like an airplane, heavier planes require bigger wings and bigger engines.

IIRC the current technology limits us to foil about 400 ton.

If the Hobie 18 is 20% heavier than a Carbonfibre boat, then you need foils that are, say, 20-25% larger. On a plane that is a real big difference when you have, for example, a 100 square foot wing. You would have to go to 125 square feet.

However, if you have a CF boat that needs 2.5 square feet of foil, you would only have to go to 3.125 square feet. That would only be an extra inch or two on each foil in span. In the grand scheme of things, that ain't much. Water is a whole lot denser than air, so changes in the lift requirements end up being small dimensional changes in the foils themselves.

Lighter is better and faster, but something that is a couple hundred pounds heavier is easily overcome with slightly larger foils.
 
Aug 20, 2010
1,399
Oday 27 Oak Orchard
Some thought provoking comments here. Perhaps a new method rather than a conversion of a beach cat would be the answer. Carbon fiber cloth is relatively inexpensive and there is also S glass and of course the biaxials. Constructing a foam mold is easy enough followed by the layup and vacuum bagging really isn't some huge mystery. There seem to be issues revolving around the necessary reinforcement for the rudders where failure is occuring. The price of a Flying Phantom isn't all that outrageous considering the development costs and the expected profit margin expected as a low volume boat would be. Toss the profit margin and I do believe a similar boat could be constructed quite reasonably. We shall see.
 
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