Wouldn't an airtight/watertight spar be enough to keep from turtling?
------ Original Message ------
Received: Sat, 28 Jan 2006 09:53:45 AM MST
From: Mike Crawford <jmichael@gwi.net>
To: harryproa@yahoogroups.com.au
Subject: Re: [harryproa] kite traction
That's one of the more unique ideas I've heard.
Randy Reynolds claims to be perfecting his system for righting the R33
cats when they go over, and says he has tested the system four times.
Many people are waiting for the official unveiling. It's briefly
described towards the bottom of http://www.r33.com/en/update/index.asp .
The Firebird catamaran folks sell a compressed gas righting system for
their 26' catamaran for $4,000, shown on their options page at
http://www.firebirdcat.com/pricing_and_options.htm/pricing_options.htm .
I'm waiting to see what Randy claims is so wonderful before getting
serious about a choice, either for a proa or for the current boat.
As for the kites, they are one of the few ways I can think of to right
a boat on on your own. If you can set up a compressed gas righting
system to keep the boat from going turtle, then you won't need a large
kite at all. If the boat is all the way over, you'll need a lot more lift.
You could conceivably strap a carbon spar underneath the deck, erect
it once the boat has turned turtle, stay it to the leeward hull, and fly
either an outleader or a water-relaunchable traction kite from it. I'd
want the spar for two reasons:
- Outleaders won't likely want to launch, or relaunch, especially
when wet, without something that will lift them off the deck/water.
- Any kite powerful enough to generate 400Kg of lift will likely be
too dangerous to handle. I've spent years traction kiting on land, and
shudder to think about controlling that kind of force. It will be safer
to use a much smaller kite, with a more horizontal force, and use the
righting moment of a spar to your advantage.
The outleader would certainly make sense if you already have it on
board. Of course, then you might have to swim to get it. I'd probably
have an emergency bag strapped or built into the underside of the deck,
or along one of the beams, with the necessary kite, lines, cell phone,
handheld vhf, flares, and so forth. This is what I'm working on for the
current catamaran, minus the traction kite, just in case.
You might need that spar for righting in any event, even with a
support boat. A number of racing and pocket cruising cats can be
somewhat easily righted by reverse pitchpoling them, but i don't believe
that a proa will lend itself to going end-over-end.
Everything would be easier if there were some sort of inflatable
righting system to prevent the boat from going all the way over. Plus,
even if the boat were to turtle, flotation would still make righting it
easier.
- Mike
Robert wrote:
> Looking at the kite boarders I started to think about how much traction
> a kite has. It would not take a very large kite to lift the lw hull out
> of the water and back over where it belongs if you were unlucky to be
> flipped by a wave. For a Harry 12m lw hull it weighs less than 350kg. A
> couple of powerfoils can generate that much lift, so surely an
> outleader kite should be able to drag the lw hull up and over.
> Is my arithmetic correct. I am not sure how easy it would be to turn
> the boat upside down to try it but It would be an ineresting exercise.
> It might need a little mast head bouyancy added using the halliards in
> light airs. The concept could be tried out with a beach cat and a kite
> from a kite board.
> Regards,
> Robert
>
>
>
>
>
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