Kite Power For Daysailing and Cruising: The thread

[eponodyne]

Hey, all:

I'm starting this thread in an attempt get all the thoughts contained Here, here, here, and to some extent here into one thread. What I'm hoping will spring from this is the success of Rick Willoughby's Pedal Powered Boats thread; a tall order, but hope springs eternal. I'm also hoping we can keep the kite-assist for cargo ships out of the discussion; except as the technology applies to smaller vessels. Most of us don't take the VLCC out of the garage and down to the harbour for a brisk afternoon's sail.

So right away we're talking about off-the-shelf and closely related technologies for the kites, which means ram-air inflated and/or inflated bladder strut kites such as are sold for buggying and kiteboarding; available from such companies as Flysurf, Naish, Cabrinha, Peter Lynn, and their ilk. These are available in a range of sizes from ca. 3 sq. m up to a 23 sq.m. behemoth from Naish, and the true enormities from Outleader. They are designed to be controllable, and are, with their four or five control lines on a short bar, and the bar hooking into a simple pelican hook.


Some leading questions: What would be the optimum hull shape to take advantage of these sails? How would it be different for bluewater cruisers than daysailers? How might the hull(s) be different, with the different hull stresses brought about by lack of mast and shrouds? How much might ballast be reduced in monohulls?

How could control be improved, to reduce need to tend sheets and lines? Could existing self-steerers be modified to control a kite instead of a rudder? How much can kite shape be optimized to provide stability in the wind window? How about semi-rigid single-surface foil shapes, as one might get with windsurf sails?


I'd also like to dispel one common misconception right at the get-go: that kites only work downwind. No, not at all, not the case. You can work to windward with a kite just fine, and I proved this by winning a tacking duel with a Hobie cat in Florida just a few years ago on a second-generation Cabrinha kite and a homemade kiteboard. Technology's improved since then. Maybe with what we learn here, we can improve on that still further.

[gonzo]

I am curious, do you tack or jibe?

[eponodyne]

Tack or jibe?

Good question. A tack when kiteboarding is more closely related to a jibe on a mastboat than a tack as most would define it-- no headsail, remember-- and a "jibe" when riding downwind is really nothing more than a turn. It's tough to explain, but once you've done it it's pretty intuitive.

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