Veal Heel for Multihull Foilers

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I'm not sure I understand this. I've got a lot of hours foiling a Rave as well as with my F3. The windward foil doesn't start to pull down until the wind is over about 18-20 knots apparent(Rave). It begins to pull down as a response to the heel of the boat: the wand tip goes down a bit further causing the back end of the flap to come up generating downforce. And if equipped with one of the bolt modifications invented by Doran Oster, it works even better.
Now, this has nothing to do with my veal heel concept multifoiler which is DESIGNED to sail on just two foils in light and moderate air. And the power foils are small foils-about half the size or less of the mainfoil. Like any bi-foiler the crew sets up veal heel. The power foil can be deployed when conditions appear to warrant it. The power foil on the multifoiler concept also uses a wand that is set to fly the foil at the correct depth as it is on the main foil and on the Rave foils. The wand(and tension on the bungee) controls foil depth.
If I understand you correctly you're saying that the veal heel concept boat of this thread will work because it is designed to sail on two foils? If thats correct I 100% agree with you.
On the other hand, a multifoiler like the Rave or F3 or Hobie trifoiler COULD NEVER BENEFIT from veal heel-they are not designed to do so and they won't ever be suitable for it.
The L/D ratio of the "power foils" on the concept boat is excellent as shown earlier.
Am I understanding you correctly?

 

No I don't think you do understand what I mean.

Lets just consider the Veel Heel effect on a 3 foil boat. Now my understanding is that when a foil is inclined beyond the horizontal in either direction it will create a small amount of a sideways vector of lift. Now if the boat leans to leeward it stands the main leeward foil ( the windward foil starts to rise ) more vertical or if the foil is vertical originally, over vertical, at this point the Veal Heel effect is gone or working against lift toward the windward side.

I feel in most practical occassions this will be the case. Also I think the windward foil will be probably working much less efficiently than expected due to its closeness to the surface and so can not be expected to be able to create much negative lift without sacrificing a lot of extra surface drag which for all intents and purposes will slow the boat down. The skipper would be far better to release the loading on the main and let the boat level for better effiecency.

Speaking of the main would we not be better off to simply move the base of the mast across to the leeward side to better balance the loading on the foils + it would incline the sail to get a lifting force from the sail as per the windsurfers ?

As to your power foil idea it maybe an ideal aspiration but in the practical sense I wouldn't be bothering to build it any time soon, far to many things to get right and even more so, far too many things to go wrong.

 

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Wayne, veal heel won't work on a three foil boat. It will work on almost any 2 foil boat-where they(the 2 foils) are the primary lift( 80% on the main foil,20% on the rudder foil).
And veal heel isn't an "effect" it is an intentional technique that is done deliberately by the skipper.
The only boat other than a two foil foiler that I can see veal heel working on is the concept boat of this thread that uses two foils for 100% of lift and two foils(one at a time) for additional RM in moderate to strong wind. The power foil/wand combination, once engaged by the skipper, holds the boat at a 20 degree angle of heel to windward and automatically maintains itself at the proper depth-just like any other wand controlled foil does.
I guess I don't understand what part of this that you think won't work. I'd appreciate it if you can help me get it.

 

I've been reading this thread from start to now, and alittle lost with all the bickering and slandering comments as to what the main purpose of Veel Heel is trying to achieve. From what i can understand is the sailor is trying to make the foil (on the moth) to tilt upwards and windard to try to pinch as much of the course he can towards the winward marker, using the foil to crab the boat towards the winward marker. Also i understand that the problem with fast boats when closed hauled is that due to their forward speed the relative wind changes and the end result the boat has to bare away from the true wind and a boat that is not so fast will set a course closer to the windward marker and thus sails less distance. Hence the reason they Veel Heal the moth. Now for a more than 2 foil boat, is it really needed to Veel heal the boat, or would it be better to change the AoA of the vertical portions of the foils to help the boat crab towards the windward marker or something like a gybing centre board.

As for RM, the tilded foils on the leeward hull won't help in the slightest, as the boat starts to tilt towards leeward, the foil will provide more lift, which will lift the boat higher out of the water because of the extra lift, but doesn't have a anti roll portion so all that will happen is the boat will be higher out of the water when it blows over. The windward foil is going to have the greatest effet on RM, as long as it doesn't stall it will keep pull that hull down. Which comes down to the fidelity of of the foil system, how quick it can react to a change.

I have a interest in where this thread heads, as i'm researching ideas to foil my hobie 18.

Dave,

 

Yep, good recap Dave.

An aspect of the heal not fully discussed yet is the pinching effect. If the boat turns on its centreline axis into the wind (as in conventional pinching technique) the apparent vs true wind position is well understood.

But if the veal heel lifts the boat without changing its centreline axis, there must be some effect, but is it more theoretical than actual, given the changeable nature of wind at the surface of the water?

 

See the paper(towards the end) attached to the first post for an in depth explanation of veal heel. One of the biggest advantages of veal heel on a multihull bi-foiler is the increase in RM-up to 20% for "free". Improvement in windward ability is another bi-product of veal heel which will work on a multihull bi-foiler as well. I have to mention again : veal heel will only work on a multihull foiler specifically designed for it.

 

Has anyone done a calculation of where the cross beam ( say 2.5m ) will be in relation to the water at 20 degrees, its gotter be getting pretty close or the leeward side will have to be pretty high ?

 

This gives you the idea-you could print it and use a couple of different scales.
The lee cross arm is at a higher than "normal" angle in this configuration....The point is to give the ama about the same clearance you give the main hull. Altitude above the water can be varied with these caveats:
1) The foil tips(main foils and power foils) must be designed and set-up(with wand adjustment) to be 2.5-3 chords below the surface at all times.
2) The longer the struts, within structural and depth(off foils) considerations,
3) strut(vertical fin) length has an affect on max veal heel-altitude can be varied with a fixed length vertical fin with no affect on veal heel.
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angles are from vertical....
beam is a little over 15 feet-with1/2 shown in the sketch...

 

Wow, this is really something.

This sketch has been shown time and again, and The Lord of Non-Foiling continues to post it with all the inaccuracies intact. He seems to be very proud of this sketch. Sadly any 6th grade art teacher, high school drafting instructor, or any physics professor would grade it a Failure.

 

At 20 deg of heel, assuming the foils remain at the same height the end of the beam (2.5 m end to end) will move vertically by 43 cm (17")

The 15' offset beam in Doug's sketch will move by 5 ft (1.5 m)

 

You have made an incorrect assumption based on the sketch presented.

This just clarifies why the sketch is so worthless. It cannot be interpreted easily, even by people who know something about the subject.

 

7.66 feet is about 2.3 m hence my original question, and 7.66 + 7.66 ie a Tri is near enough 15 feet. Now one doesn't have to be a rocket scientist to work that out from the drawing or is that too difficult for you Paul B.

Any chance we can get away from "have a pop at Doug at any opportunity" to a reasonable discussion on foiling ?

 

I took another look and you're right: I should have looked closer; my number can be halved; better, but 2.5 ft/76 cm still seems quite a lot.

 

You might note that I'm not the one who mis-interpreted the drawing, even though I don't work on rockets.

Why don't you count up the mistakes on that drawing and tell us how many you find? Shouldn't take a rocket scientist to count them up.

I really hope you follow The Lord's advice on foiling. That way you will be just as successful as he has been.

 

So, there it is... Another dispute regarding the input of Doug Lord's so-called mastery on the topic and just who is the common denominator... Why it's our boy, Wayne, the defender of the Lord mystique.

Want to get some non-fevered input on the topic. Do what I suggested several posts ago and make friends with Sam Schneider, get your butt on over to Sailing Anarchy where there are real foiling experts and post your interests with them.

If you are lucky enough and Doug doesn't make his presence felt, you'll get all sorts of guys to come out and offer-up the best of information that would take you years to discover on your own... if ever. Write them offlist and the world will open to you like never experienced on this list.

Gary Baigent is running on SA as CoxCreek. You'll find the guys who did the Canadian C-Class cat there, something like two dozen, or more, Aussies and Kiwis, who have hundreds of hours of foil experience in all areas of the application and a friendship potential that will make your head spin.

This is simply a friendly nudge. If you are really looking to understand some specific applications in the foiling genre, do yourself a favor.