30 mph for 3 G

[Daniel Noyes]

Hi all
since Frank posted the sail rocket I have dug up some sketches I did for a home built speed sailboat (soft water).
Her looks hark to a old stern steering ice boat.
The business part of the rig is based on the Yellow Pages Endevour concept of small planeing hulls. Three flat wide hulls, two up front and a small skimmer at the stern, I have drawn various rigs for this craft but I like the simplicity of a large low lateen rig on Bipod mast.
I think a 16' one man version could be built for around 3,000$ and might sail at 20+ mph.
I will build a model some day when I have a spare munite and see how it performs.
Dan
http://dansdories.googlepages.com

[ben2go]

OK,you have my attention.

[ahp]

There was a book titled "The Thirty Knot Sailboat". The author only built a scale model which he sailed on a dry lake in the South West. In the spring these lakes do get some water in them. His design, he made several, was like an iceboat with hydrofoils.

[Daniel Noyes]

Could this be the fastest wooden sailboat ever!?
Monitor, designed by Baker and built by the U.S. Navy and Baker mfg co. sailed on stainless steel hydrofoils to over 30 knts. in the 1950's (swimmers and fish beware)! boat is in the Mariners Museaum at Newport News VA.
http://www.wind-water.nl/monitor_port_1.jpg
My idea would be quite a bit simpler and cheaper though not as elegant. Ill try and get a few sketches scanned and on line.
Dan
http://dansdories.googlepages.com

[ben2go]

Wouldn't it,in theory,be possible to achieve more than 30kts. by sail using hydrofoils?

[Dan McCosh]

The Hobie Trifoiler was a production hydrofoil that would do more than 30 knots.

[Captain Blight]

Here's my take (http://www.woodenboat.com/forum/showthread.php?t=88677).

[frank pedersen]

Hi Dan: You too have my attention, but I am slower to respond. Three thoughts: (1) I think I get the idea, but a drawing would be helpful. (2) You mention a lateen rig. In a book I really enjoy, Sail Performance (2nd ed.) by C. A. Marchaj, there is a chapter on wind tunnel comparisons of various rigs. The lateen comes out well, but the most amazing result was the power of what is called the crab claw. There is a certain similarity of the crab claw to the lateen rig, but the crab claw, at least in these comparisons, showed a remarkable superiority, Perhaps you have noticed pictures of top-level competition in the Sunfish. They usually have the tack of the sail almost on the deck, which causes the boom to angle upward. That makes the lateen rig a virtual crab claw. Interesting. (3) After seeing on You Tube pictures of Moths on foils, here is my proposal for affordable speed: (a) a Moth on foils with hiking racks, plus (b) a Spitfire wing shaped sail with full-length battens, plus (c) a canting mast that can be angled to windward (shrouds are tightened or loosened with a lever) to have a touch of the lift pattern of Sailrocket.

[Captain Blight]

Good ideas but foils are pretty spendy. And if you don't spend the money for someone else to make them, then it's a big investment in time to do it yourself. Dan, what's wrong with the D&DDD idea? Two flat-bottomed hulls could scream right along!

[Daniel Noyes]

Hi all
There are two important ideas behind the Yellow pages endeavours' three short, wide planeing hulls:
1 a short wide hull is very efficient at generating lift at planeing speeds. I saw photos of an old experiment, a planeing surface tow tested in a tank with holes drilled at regular intervals fore and aft along the plane and measuring tubes to test the water preasure along the lenght of the plane, just like a wing in the air or water the plane generated most of it's lift along the first third of it's surface. A windsurfer is mabey 10ft long but only 2 ft wide so its lifting surface is about 2 ft, to sail fast a windsurfer must shift weight aft untill more than half the board is out of the water, this reduces the drag of the trailing portion of the hull. With a wider shorter hull you get alot more lifting surface and alot less drag from the rest of the hull.
2. the third hull regulates the angle of attack of the other two hulls, short wide hulls tend to squat when power is applied. By seperating the hulls fore and aft and joining them rigidly the hulls can be kept at their optimal planing angle.
Here is the sketch I pictured the boat with a varnished main beam and white hullsm mabey even a canvas nonskid deck on the hulls, like the machine just came out of Hereshoffs or a Burgess work shop at Marblehead. The large dagger board is for up wind work, likely at slow displacement speeds. I designed this boat to be carried on a fullsize pick up with a roof rack. Neat thing is with the sail and masts lowered and secured this boat or a bigger version could be left on a mooring.
Dan
http://dansdories.googlepages.com (http://dansdories.googlepages.com/)
http://farm4.static.flickr.com/3115/3098800715_f613f84010.jpg?v=0

[Captain Blight]

HOLY CATS! You'll shoot yer eye out, kid! But it looks simply grand, I like the idea of the varnished springplank and the cream-canvas decks.

I see now why you were thinking Sunfish-type lateen. You'd really want this thing to sail on her feet.... you could always power it with a great big kite!

[Daniel Noyes]

yeah a kite, if it could be reliably controlled, would be ideal.
Dan
http://dansdories.googlepages.com

[Daniel Noyes]

Thanks Blight!
thats just what I was going for, I got to see Amarillis II at the Bristol RI a few yrs ago and was very impressed.
I think you are right on about the efficency of the wide floats, highly efficient in planeing mode and very poor in displacement mode. Im pretty certain that the drag on the boat will actually decrease significantly as the floats begin to plane, as opposed to most sailboats where drag increases steadily with speed. I would expect performance up wind to be about as good as a PDR or opti pram, the deep dager board is specifically for efficient slow speed lateral resistance, I tucked the rear float in at the stern to give a little better flow by the rudder. The boat caries the large low sail to power it past the displacement/forced speed onto a plane, the hull speed of the floats is likely 2mph tops so they should begin planeing relatively quickly as the boat is steered off the wind, once the boat was up it would break free and accelerate rapidly. The only way to test the idea is a decent sive scale model, 1/4 scale would work well, the scale weight including a simulated skipper is important as weight will be a big factor in determining if this design is feasable.
Dan
PS Ill post some of this to the thread.


Some thoughts on your design: First, WOW, that looks like it came right of Cap'n Nat's drafting table. Line, proportion, scale, all of it looks like it's just an evolution of Amaryllis, what she would have become had things drifted that way. Maybe a little bit of iceboat in there too.

Second, I've unfortunately got to question your use of square floats: although it's true that a long narrow surface is much less efficient in planing mode than a short wide one, I think you may have gone a little to far the other way. It would seem that off-plane, your craft would be draggy and hard to steer. Maybe that's just me.
http://farm4.static.flickr.com/3115/3098800715_f613f84010.jpg?v=0

[P.I. Stazzer-Newt]

Read "Icarus - the boat that flies" by James Grogono.

"If I have seen further..."

[Daniel Noyes]

looks interesting, Ill see if the library can get it.