The Articulated Sailboat

[ancient kayaker]

This idea evolved in a kayaking thread but I thought it deserved informed comment from a wider audience.

A rigid sailing assembly consists of a mast attached to a crossbeam, which supports a Bruce foil at each end. The sailing assembly is attached to a hull by a large vertical axis rotary bearing. Hydrodynamic force acting on the Bruce foils produces a vertical force which in turn acts on the moment arm of the crossbeam, and the resulting moment cancels the heeling moment of the wind acting on the sail. The Bruce foil is an established concept.

Steering is done by pivoting the assembly. With the clew of the sail attached to a kind of bowsprit as shown in the first sketch, the sails thrust is rotated at the same time as the foils. This is the new feature.

The advantage of this rig is its ability to tack virtually instantaneously as shown in the second sketch. It is particularly useful for long hulls that are slow to turn and may be caught aback during tacking. In a new design tt may allow higher speeds to be achieved by using a very long narrow hull which can still tack handily in narrow waters. The concept allows a non-planing monohull to be optimized for straight-line speed without compromising its agility.

[Chris Ostlind]

This is somewhat on the same subject, minus the Bruce Foils and sail rig, so I'd like to show a couple of pictures of my Canadian buddy, Bob Stuart, and his very quick HPV, Lamordinghy, equipped with his own, SpinFin, pedal drive unit.

As you can see from the photos, Bob's boat is setup with a rotating steering system that doubles as a stability enhancer for his boat. The immersed edges of the amas are just slightly angled inwards, though they do not act as lifting foils. The steering is accomplished through a continuous loop line that connects both ends of the ama/aka structure. Pull on the line on one side and the boat turns smartly.

These pictures were taken when Bob made a visit to Utah several years ago. I got to drive the boat and it is very responsive to turning input, totally stable and very fast.

Hope these help along your path to further kayak enlightenment.

Chris Ostlind
www.lunadadesign.com

[ancient kayaker]

Without a sail Bob would not need the lifting foils. The steering foils look to be well forward of the stern, closer to midships for a faster turn. Slow turns were the problem in my previous sailing kayak. If I can get the mechanics to work I will implement the idea in my next effort.

I'm still hoping to get more feedback, because it seems such a good idea it should have been tried before. Maybe someone will come up with a picture of something old, wild and weird.

If it works I will need a better name, "articulated sailboat" is not very inspiring, perhaps Bob wouldn't mind if I called it the spinsail.

I like it AK-you should put it together!
"Foil Around" or "Rota Rigger"(just kidding!),"Foil-yaker System",
Well, I tried.....

[ancient kayaker]

Foil Around is my favorite to date although UFO (Undesirable Floating Object) has also been suggested by a more traditionally-oriented sailing buddy.

Currently I am trying to figure out how to combine it with a wingsail. Spin-a-wing? Whatever: it will happen!

[Chris Ostlind]

With no wish whatsoever to "go a wet toweling" on all these ideas... Bob Stuart's SpinFin named product had to do with the pedal drive system and its amazing ability to deliver power to the pedal powered kayaker.

Check the records for HPV's and you'll see Bob's credits named properly in the firmament of the genre.

I do, however, like that you have adapted his "Spin" concept to yet another form from the boat as shown.

Bob has since sold his tooling and interest in the SpinFin product and moved to the wide open plains of Canada.

Please do, go forth and name the Spinning aspects of your own design work as it suits your interests. There's no wanky business claims as far as I know.

Chris Ostlind

Originally Posted by ancient kayaker

Foil Around is my favorite to date although UFO (Undesirable Floating Object) has also been suggested by a more traditionally-oriented sailing buddy.

Currently I am trying to figure out how to combine it with a wingsail. Spin-a-wing? Whatever: it will happen!

-----------------------------------------------
"Spin Tacker". "Foil Spin System" of "FSS" ----enough!

I think you have combined some good ideas in a unique way-I can't wait to see how it works!

[Chris Ostlind]

Then, there's this to consider... the very interesting entry in the 2008 Watertribe Everglades Challenge by Randy Smyth. He used a rotating (spinning) aka/ama assembly. When he sat way outboard on the windward side of the boat, this system allowed him to rotate the leeward ama forward for max resistance to capsize AND at the same time, rotate his body weight aft, to provide a serious counter balancing effect to his big rig and screacher.

Ingenious and intuitive and very much in keeping with a guy who has won so many multihull titles, worldwide, that they are tough to count.

Unfortunately, the Lobotomy machine broke while leading the race and had to retire, leaving the victory to a full-tilt Tornado catamaran with a very experienced crew.

[ancient kayaker]

The "front wheel steering" concept may have a fatal flaw, see post #145 in this thread:-

New High Performance Monofoilers

Of course I can fix that by having a conventional stern rudder as well, but it's a valid point.

[bistros]

Originally Posted by ancient kayaker

The "front wheel steering" concept may have a fatal flaw, see post #145 in this thread:-

New High Performance Monofoilers

Of course I can fix that by having a conventional stern rudder as well, but it's a valid point.

Reality battled with theory once again, and as usual reality won. Julian Bethwaite's testing of his father's foiling project (using a 49er hull & rig) has worked fine with front foil steering. Julian seems quite confident the front foil steering is safe, even at 20+ knot speeds under sail.

The only circumstance he noted as problematic is when moving at very low speeds where the rudder blade is needed for maneuvers - at speed they remove the rear rudder.

--
Bill

Originally Posted by bistros

has worked fine with front foil steering. Julian seems quite confident the front foil steering is safe, even at 20+ knot speeds under sail.

--
Bill

==========
Really? Remember you said that... Since the boat has not even been two boat tested -much less raced- there is not enough info yet to make any judgement vs a conventional set up.

[ancient kayaker]

Originally Posted by bistros

Reality battled with theory once again, and as usual reality won ... Bill

Well, reality hsn't had a chance to strike yet since I haven't tried it out!

From Julian on SA today:
"Bora is correct re steering System, in fact we end up with poor steering because we underestimated the loads on horn.

The pitch is very stable.

Way to early to comment further, there is simply way to much to learn, next sail is likely to be Thursday.

JB "

[Chris Ostlind]

Originally Posted by Doug Lord

Really? Remember you said that... Since the boat has not even been two boat tested -much less raced- there is not enough info yet to make any judgement vs a conventional set up.

Each and every one of the brain exercises you have produced in the past has been accompanied by loud proclamations from you as to how they will perform, how they will function technically and how they will set the world on fire.

And here you are, criticizing both Julian and Bill because the boat in question, which is actually built and sailing mind you, has not been two-up tested, not raced and apparently there's not enough info to actually know what it can do.

Irony comes to mind.

[ancient kayaker]

I wonder if anyone is still subscribing to this thread? Well, builidng is underway on this and other projects in related threads. I will post pictures soon on progress.