kite dinghy

[sigurd]

It leaks and is hard to open.
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bungy

[sigurd]

lots of bungies and their associated devices and some unrelated.
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54m x 4.
the 2:1 advantage the sheets have over the pilot is eliminated when the lines are extended, by attatching the sheets directly to the yellow/black leader lines.
There is a dubious unsafety release which is supposed to reel out all but one line.
The low stiction on the actuator sheave requires a stiff tension on the actuator loop's tightening bungy.
The sheeting blocks are clipped to the pink loop when the lines are extended.
Port sheet is jambed. Padeye burned. Uneven length of reeled lines.

[Tim B]

Either clean up the transom flap and hinge the flap nice and cleanly, or just get rid of it. and either laminate up the hole in the transom, or tidy it up and glue in a perspex window.

Personally, I think the systems on this boat will require very careful thought and probably redesign (or renewing at least). Do not rush it, and think it through well.

Tim B.

[sigurd]

Indeed.

[sigurd]

.. ..

Very interesting! How's the performance-can you describe some of your experiences with the boat?

[sigurd]

I broke the daggerboard so I haven't used it alot. It moves quite erratic.

[frosh]

Hi Sigurd, I have thought about doing this as well but figured that it would be very difficult for one person to control. What you have is something akin to putting a windsurfing rig onto a large dinghy hull. It will not give the performance of the original concept.
I decided that the kite dinghy needed a purpose designed hull and probably a crew of two. One steering and providing balance, and other controlling the kite lines through a sheet and pulley system to gain mechanical advantage.
I decided to not go ahead as I thought that it would be too slow as the sailing weight of the hull and crew would be quite large.

[DanishBagger]

I am thinking that it needs a hull, similar to a snowboard. I.e. having a long keel (horisontally), or two daggerboards placed strategically at both ends of the boat to help it track properly. Perhaps having the aft one be a (very) balanced rudder.

Ideally, I would make a pivoting piedestal that I could move (when the kite is not up) to experiment with the ideal position. If that piedestal was designed properly, you wouldn't need another person on board.

If you haven't already and want to read about some of the conclusions regarding kite boats from one of the pioneers google Peter Lynn of New Zealand. I did last night but his sites were down or I would have posted a url here. It is definitely possible to build a very fast kiteboat and he has drawn the conclusion that a monohull-very lite- with a planing hull is the best solution. He inspired me to design a very light weight single person kite foiler that has not been built but that I think would be extraordinarily fast-if a bit dangerous. As you probably know the "air chair" delta foil has been adapted for kiteboard use..
Kite boat systems offer the potential of 100% eliminating heeling force and give you plenty of lift to play around with. Another advantage of a small light monohull is the ability to paddle out away from the beach to launch the thing thus not incurring the wrath of beach sailors for taking up too much space; also reduces the danger to others from the sharp kite lines.

[sigurd]

I can launch, land, and sail alone. I have not yet seen what happens, other than hardware failure, at higher power levels, so I don't know how much canvas I can utilise in what wind. With the 12sqm it seems to plane in less wind than the sailrigged e-dinghy. Overpowered, when the kite runs, the bow will lift and be dragged to leeward, and the boat will heel until there is little keel left in the water.
There is a large difference between this pull and the pull when the kite is parked for highest pointing. Thus windward work has felt slow. The lateral running track could be used to move the towpoint to leeward if I get some proper blocks. Any recommendation to blocks which will not jamb, and are matched to the 300kg+ lines could be helpful. Both front lines could run through the same block since there is no relative movement. The lines are between 1 and 2mm.
There is no need for a mechanical advantage on the sheets.The kite is easily steered with light tugs.

[Tim B]

Performance and handling will also depend very much on where the kite is being flown on the boat. This must be considered carefully and I wouldn't expect there to be a simple answer.

Tim B.

[sigurd]

Too far forward and the transom sinks, instant bathtub.

[cristofa]

Sigurd - in your email you said

"I found your pics. You had a little bar on the foredeck to place the towpoint? where was the reel?"

The pics are at Kites

and the 'little bar', with the towpoint at the end, rotated about a point just ahead of the dagger board - I found that windward performance was significantly improved by moving the towpoint to leeward.

The reels were mounted below in the cabin. There was one winch for winding the lines in and out, and a differential gear device (which could be locked) to pull one line harder than the other.

As to what became of the boat - I'm afraid I cut it up a few months back. I could not see myself returning to the project, and it was taking up space in the garden.

atb ... Christopher

www.rocat.co.uk