Subject: Re: [baidarka] Re: Sail Plans
From: Pierce Nichols (forkbomb@earthlink.net)
Date: Wed Sep 03 2003 - 11:07:17 EDT
At 09:20 AM 9/3/2003 -0600, Tom Yost wrote:
>Have you considered a wingsail ?
>
>
>The following LINK is to wing sail designer Mladen Milidragovic at "Wing
>Sails" in Vancouver, BC. He has patented a fairly high aspect ratio wing sail
>that is intended for kayak use. It's profile creates such a low heeling
>motion that he sails a standard size kayak ( 21''-24") beam with no need for
>an ama setup.
These soft sails look a bit like the form that Marchaj talks about
in chapter 13 of 'Sail Performance'. Interesting note: switching from a
round to a parabolic leading edge would boost the peak Cl of his rig 25%
with no substantial increase in drag, according to Marchaj's tests. A
foam/fiberglass leading edge of appropriate shape would be trivial to
fabricate -- just cut the shape out of foam with a hot wire, and glass it
over. If it was possible, collapsing the upwind skin and just sailing on
the leeward skin would boost performance even more, but that's probably a
bit complicated if you want to tack.
That said, I see a potential fundamental problem with using
wingsails in a kayak. They are by their nature primarily upwind sails --
while they can easily double the performance of even the best conventional
rigs upwind, their performance drops off markedly past a broad reach; far
enough past, and they will heal to windward (a situation that seems nearly
certain to lead to a capsize). In order to use their drive this
effectively, a wingsail boat needs plenty of lateral plane area... what
kayaks generally don't have. Has anyone sailed a kayak with a wing?
-p
Mars or Bust!
www.marssociety.com
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