New High Performance Monofoilers

Hear hear!

But Lewis Carol was in fact a virgin...

 

In what sense?

 

In the sense that he never foiled on a design of his own, at least.

Wait, am I confused?

 

When a thread gets to this point I just quit.

'bye

 

Does anyone have thoughts on why Hydroptere is going so fast? She is big and powerful, but uses surface piercing foils that throw tons of spray. How did the early surface piercing Moths do? Why did the bi-foil setup prevail?

 

Funny, I didn't see my next to last post as a personal attack at all. More like a satirical commentary on your propensity to wander about the dreamscape of your foiling obsession. Much like Alice in Through the Looking Glass, you dance about, flitting from one nonsensical foiling escapade to another. Never touching down, never really getting that boat done, much less sailed and proved. I very clearly stated that the whole thing was done in jest. Are things going so badly for you that you've lost what little sense of humor you once had?

Bubba... get a job, save some money and finish that contraption of yours. The foiling community awaits your shining light of brilliance.

 

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Before John Illett and Ian Ward first foiled successfully on bi-foilers, Andy Paterson and Brett Burvill had both foiled with three foil surface piercing arrangements with Burvill the first Moth foiler to win a race. But even before that Frank Raisin had foiled a Moth with a multiple foil arrangement in 1972!
In the Moth class the bi-foil configuration prevailed because the race winning surface piercing arrangement that Burvill used was outlawed as violating the "anti-multihull" rule within the Moth class. I wrote Burvill a while ago and he is convinced that if that configuration hadn't been outlawed it would have been at least as fast or faster than a bi-foil system. I'm not convinced of that but surface piercers have a major thing going for them: the faster they go the less foil area they need. Bi-foiler designers have to pick an area that allows the boat to take off relatively early while not penalizing top speed too much.
But it's not all rosy for surface piercers: the foil system develops lift right up to the air/water interface and because of that a surface piercing foiler has a greater tendency to ventilate the foils causing loss of lift and possibly a crash.
Hydroptere is an extraordinary boat that uses the advantages of surface piercing foils to the max-can't wait to see her go after the record again.
see the "fences" on hydropteres foils-used to prevent ventilation(the ridges you can see on top of the port foil):

 

Does a bi-foiler have the advantage of allowing the skipper to cant the rig whereas a tri-foiler sails flat? The reason I ask is that I have built three tris and a cat with canting rigs. The results are very impressive. Also as a sailboarder who did some racing, back when it was popular, I found that the rig cant angle was key to speed. Everybody would just "hook in" and stand straight whereas on marginal days I'd not "hook in" and plane away from everybody by getting the cant optimized.

 

Rohan Veal invented the technique of sailing a Moth heeled to windward. It unloads the vertical fin, reducing the tendency to ventilate that it would have if loaded. It increases righting moment(regardless of altitude) by ,roughly, one percent per degree of heel. Most Moths and other bi-foilers sail at 15-20 degrees upwind. There is also a gain in vmg upwind, similar to the gain from using a gybing board, because the lift from the main foil is providing all the vertical lift and all the lateral resistance required.
PS John: would like to here about your boats and how you canted the rigs-sounds great.

 

three (4) foil "bi-foiler"

One of the great advantages of a boat like the Hobie trifoiler, Rave or Dr. Sams new Osprey is that that dual wands operate independently allowing the boat to develop all its own RM without input from the crew. Hydroptere and every surface piercer I know of develop RM differently by increasing the separation between the center of lift of the main foils and the boat CG as it heels(leeward foil develops an increasing amount of lift). Hydroptere uses movable ballast as well.
I've been toying with the idea of a hybrid: a "bi-foiler" that uses retractable
small foils in each buoyancy pod-primarily in heavy air upwind. The point would be to increase the RM of the boat boosting upwind speed. The foil would be deployed in such a way as to hold the boat at a designed angle of veal heel along WITH crew participation. A target might be to add 50% to upwind RM and that would require a foil about half the size of a Moth mainfoil.
Disadvantages include the fact that two foils would be required and the additional weight. The gains could be appreciable, allowing a substantial increase in SA.
In light air the foils are retracted but the boat still has all the extra SA. So the gains would be not only upwind in heavy air but downwind in every condition and upwind and downwind in light air due to the extra power.
Takeoff would be significantly earlier than a "normal" bi-foiler....
Bradfield and Ketterman have already proved that the extra drag of a third foil is more than made up for in moderate to heavy air by the virtually unlimited rm available with their system. I think that it would be ideal to have these "power foils" able to be deployed without an altitude control system-a preset angle of incidence might work.

 

Actually, for the sake of accuracy it could be noted that Moths had been sailed heeled to windward for years before Rohan entered the class or foilers came along. 18s also sailed heeled to windward for some time, although apparently it was a fashion to some extent. Even Lasers have been heeled to windward; see Bourkey's book.

 

The technique is different on a bi-foiler-thats why its called "veal heel" . I should have said that Rohan invented the technique of sailing a FOILER Moth to windward. Not only is the technique different the physics of what happens, largely, ONLY applies to a bi-foiler.

 

Geez Chris, how could you possibly think that you could inject reality into a purely fantasy stream of consciousness?

As long as we're going whole hog with retracting foils, heeling Veals and all that one could possibly toss onto an otherwise spare and purposeful craft... how about this one that I've been toying with lately?

We start with a tri config of a foiler with, you guessed it foils on the ends of the akas. There are no aka end vestigial floats, as they only get in the way of a purist’s boat and visually clutter the design. Yes, there's another foil on the rudder and of course there's that robust foil at the end of the daggerboard board. Because we only sail in the really windy parts of the country, there's no reason to be concerned about the take-off speed. If the wind is less than 12 knots, we just don't bother. Wouldn't be sporting anyway.

Now, here's the twist with my remarkable brainstorm... as the currently, being-toyed-with boat gets into the Heel O' the Veal and the windward aka(and no retracted foil) immerse, the boat just continues to roll to windward, right on past our icon Veal into a whole new territory that I call Angle d'Abolic. The previously extended aka retracts into the now speeding hull for a perfect hydrodynamic shape.

With precise coordination, unaffected by sea state and wind conditions, I pull on my discreetly powered-up hydraulic lever and out comes a whole new, foil on end of aka system (FEAS) that extends up and out of the hull at what would be a 45 degree angle, should the craft not have already rolled well past that reference point. When fully deployed, the Systeme FEAS d'Abolic comes into its own as a foiling vessel of serious anxiety.

With the mast now canted well to windward... so far over, in fact, that it now becomes a lifting wing in the atmosphere and not just a sail as you may have known it just seconds before. It is at that point that some real magic takes place.

A whole second sail system is lifted from a secret compartment on the hull and it takes on the principal duties of the former rig. The Hyper-Heeled (TM) rig, is in full lift mode, the upright rig is driving like a drunken moonshiner and the Systeme FEAS d'Abolic is doing the heavy lifting from the water side of the craft. Dare I say that this entire function is automatic, requiring no input from the pilot, as it is keyed to velocity, as well as sensed angle?

While all of these coordinated devices are engaged in the dance of beauty, the main and rudder foils are also undergoing a fabulous change of their own... yes, you may have guessed it, they cant!!! And why not, really? The technology has been underused by the monohull genre, yet it retains that unmistakeable power that only advanced sailors will recognize.

Yes, it is a bit on the overly complex side of the equation. But... and this is the important part, it works when I run the calcs, (I can supply a sheet with a long list of fairly vague and self-important numbers). It can be built (it will be built) and it will take over the previous foiling revolution with multiple lifting surfaces and revolutionary design techniques never before seen in the genre of foiling machines.

As you can see, I firmly believe in design complexity. In fact it is the driving philosophy of my refreshed approach to foiling craft. Limited thinkers will be forced to sit back and weep at their deep lack of vision, while production examples will be shipping to the youngest of sailors who augment their home allowance with a simple paper route.

No need to send us an email, we already know your ISP number and your propensities for foiling dreams.

We own the revolution!!!!

 

To answer your question about some of the boats... the last two are general copies of Hydroptere. One 22 ft and the other 20ft. Canting of the masts is just done with crude lines pulling laterally on the loose stays; producing 10 degrees of cant. Nothing fancy but it works. The jib is on its own mast. The head is hooked onto a hook on the main mast. The foot is loosely attached with an adjustable line. The jib cant is maybe 20 degrees in strong air and very noticeable. On one of the cats this produces enough lift that the bows do not dive at all making it considerably faster and very nice to drive hard. Next change planned is to add center foils to the latest Hydroptere like tri and cant the whole boat on one ama and the center hull -- the reason for my questions about foils and canting. Thanks for the tips.

 

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Your boats sound very interesting-post some pictures if possible. I'd like to see what you've done.