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Tomahawk

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hollandsd View Drop Down
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Post Options Post Options   Quote hollandsd Quote  Post ReplyReply Direct Link To This Post Topic: Tomahawk
    Posted: 12 Mar 09 at 12:35pm

I have head of foilers having problems with large carp on small lakes in aus and the states when they hit them at top speed, a large fish can wreck a boat, and the fish doesent fair to well either.

 

Dan

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Medway Maniac View Drop Down
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Post Options Post Options   Quote Medway Maniac Quote  Post ReplyReply Direct Link To This Post Posted: 12 Mar 09 at 11:16am

My guess is that it'll ventilate as the foil nears the surface and the hydrostatic pressure drops. Below that you'll have lots of drag off the transverse ridges - a bit like the step on the Cherub on the Spy Photos thread, actually.

The Cherub's drag will drop as planing is achieved, and I'm thinking the stepped foil's drag might drop once ventilation occurs. Again, interesting stuff, and l look forward to seeing how it works out in practice against conventional planing boats. My guess is slower in F1, 2 & low 3, quicker thereafter - till it's weed-bound. Anyone know how the foiling Moths cope with weed, or are they so quick and their foils so sharp they just cut through it?

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Post Options Post Options   Quote robinft Quote  Post ReplyReply Direct Link To This Post Posted: 12 Mar 09 at 10:00am

Originally posted by Peaky

Does the foil ventilate due to proximity to the surface, or due to increase in velocity?

Great question which I certainly can't answer but as a complete layman I did wonder if water flow is attached over the whole of the upper surface at low speed and then detaches leaving flow over 2 thirds and then one third as speed rises - hence the steps. The bottom surface is completely flat.

It would be interesting to try the Tomahawk foils on a Moth, rather than simply compare the two boats as is.

 

 

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Post Options Post Options   Quote Guests Quote  Post ReplyReply Direct Link To This Post Posted: 12 Mar 09 at 8:37am
Does the foil ventilate due to proximity to the surface, or due to increase in velocity?
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Post Options Post Options   Quote alstorer Quote  Post ReplyReply Direct Link To This Post Posted: 10 Mar 09 at 11:06am
Steve: according to Linton at the show, the jib was specified by Phil Morrison early on, and was inspired by ICs. The idea seems to be both to enable people to "sail to the jib" (hoping to attract double-hander sailors) and also to generate more power lower down.
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Post Options Post Options   Quote getafix Quote  Post ReplyReply Direct Link To This Post Posted: 10 Mar 09 at 10:36am
jib could be very handy, I've wondered about this on moths (although will freely admit to being too lardy to have sailed a foiling one!) - should help with the flow over the back of the mainsail especially in the transition phase between foiling & non-foiling. Could really help downwind in this respect and possibly allow much larger angles. I thought the main on the show boat was quite a full cut (but I'm no expert), and sail dev was something mentioned as work in progress.
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Post Options Post Options   Quote Steve411 Quote  Post ReplyReply Direct Link To This Post Posted: 10 Mar 09 at 9:28am

Chris,

Why 2 sails?

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Post Options Post Options   Quote Medway Maniac Quote  Post ReplyReply Direct Link To This Post Posted: 09 Mar 09 at 8:35pm

The efficiency of the foil with those steps on the low-pressure surface (which, after all generates 2/3 of the lift) must be much lower than that of the Moth foils. Whether it is sufficiently efficient to be faster than a planing hull will be interesting to find out.

But as others have said, foiling is a special sensation, so anything which makes it available to the masses must be good, fast or not.

I won't be buying one for the Medway, however, any more than I'd buy a keelboat with a projecting bulb keel (like a K6). Weed will destory your speed by half-way through the race...

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Post Options Post Options   Quote Rupert Quote  Post ReplyReply Direct Link To This Post Posted: 09 Mar 09 at 7:52pm
I liked it - I pictured a folded piece of paper inserted in a pie, ready for the spy to find!
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Post Options Post Options   Quote Ross Quote  Post ReplyReply Direct Link To This Post Posted: 09 Mar 09 at 7:40pm
Originally posted by Rupert

[QUOTE=Ross] But as the saying goes,
the proof is in the pudding.


QUOTE]


It does?



Granted, it should have been "the proof of the pudding
is in the eating". But it's an abbreviation, let it go!
Ross
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