Hobie Trifoiler replacement

[waynemarlow]

Has anybody done any in depth design for a Hobie Trifoiler replacement, they are a great machine, but built like a tank and have speed limitations. Thinking along the lines of a very light weight custom boat perhaps with outward facing Bruce foils to keep complexity down but do like the twin sail arrangement as it really does work better than predicted by some.

Looking for speed here rather than being able to sail upwind and down but being able to get yourself back to a starting point would be cool.

Any views guys & gals.

[Gary Baigent]

How about my fantasyland "C Class" tri foiler - which I intend to start, anytime soon, sometime soon - soon as I finish the other .........??

[waynemarlow]

Interesting as the aircraft have gone to this type of arrangement for efficiency of the foils, are the out riggers wing section as they could also offer consdierable lift at 30 knots.

[Gary Baigent]

Foils and winged beam will be like this - here on my other boat G. Marx.

[ancient kayaker]

I have been looking at an idea using the Bruce foils as suggested, simpler, lighter and maybe less drag than the Hobie arrangement. However, I was considering a monohull with the foils on outriggers, and a planing hull instead of a rear foil. More for simplicity than for efficiency, in a boat that would function well in non-foiling mode as well. I need to do some experimenting though.

[sailsocal]

Originally Posted by Gary Baigent

Foils and winged beam will be like this - here on my other boat G. Marx.

Interesting foil design, did you design and build them yourself? What material are they?

[Gary Baigent]

Sailocal, the 11 metre wing beam is strip planked paulownia, a lightweight, non rotting timber that is grown here in NZ in a few plantations, halfway between balsa and cedar in weight, then glassed inside and out; the beam was built on two quarter moulds then glued together after the insides had been glassed, then the outsides glassed and reinforced with carbon bands. There are also diagonal struts running from main hull to shroud attachment points to triangulate the rigging loads, may not be necessary but there all the same.
The foils are stripped Port Orford cedar, (also plantation grown here, very light and very strong, supposedly the best timber there is) glassed and carbon reinforced and glued/glassed/carbon ed solidly into the floats, no cases.

[waynemarlow]

OK I like the concept of a delta wing type boat with Canard at the front. A few questions then. The lift ( height ) of the front can be easily controled with a wand AKA the Moths, sorted. The outer perhaps would be better as a Bruce foil as it would then self regulate, with your foils Bruce how do you intend to control the amount of lift as if it gets too close to the surface, you can get all sorts of cavitation problems ?

A twin mast set up as per the Trifoiler could lend itself to the Delta cross arms nicely, but how do we get balance in the sails through the boards ?

Keep the suggestions going as the 49er developmental foils is not unsimilar with canard front and cross foil at the back.

Where would you put the rudder as the canard aircraft have an additional rudder at the back. Would the front rudder work at low speeds ?

[tony-uk]

hi
i am making a sail aka ama rig that can fit any sea kayak
i will test it and if all goes well i will build some foils
my progress will be logged

here
http://kayakmaran.pbworks.com/FrontPage

[Herman]

The original that the Hobie TriFoiler is based upon, was slightly larger, and WAY lighter.

A really great concept, hope it gets continued some day.

[powerabout]

I wonder how a trifoiler would perform if all carbon incl the masts.

( I have a trifoiler but not ready to sail yet still making spares for it)

[Doug Lord]

Word is Greg Ketterman(designer of the Hobie trifoiler) is about to debut a new foiler-maybe this year. And Dr. Sam Bradfield is about to debut a new all carbon version of the Rave-see rendering below.

[pdqsailor]

Tom,

What would your thoughts be on a swept back or delta foil design with small end plates (like airplane wings have) to prevent vortice drag? These would be somewhat larger than ventilation fences and shaped to profile the foil.

[tspeer]

Originally Posted by pdqsailor

Tom,

What would your thoughts be on a swept back or delta foil design with small end plates (like airplane wings have) to prevent vortice drag? These would be somewhat larger than ventilation fences and shaped to profile the foil.

End plates do not prevent induced drag. At best they can reduce it a bit. Better to simply increase the span. You get more induced drag reduction for the same additional wetted area.

Swept back is a good idea. It can increase the incipient cavitation speed.