Subject: [harryproa] Re: mast bouyancy
From: "robertbiegler" <>
Date: 2/12/2006, 6:10 AM

--- In, Mike Crawford <jmichael@g...>
>   Very solid arguments for fixed masthead buoyancy.

My guess is that mast buoyancy or leepod are only good to deal with
errors of judgement in moderate conditions.  If you flip a cruising
multihull by carrying too much sail because you need to get off a lee
shore, the conditons are likely rough enough that your masthead
buoyancy breaks your mast, unless te mast is specifically engineered
for the purpose.  (Relevant case study is a 12 m Apache catmaran in
the Round Britain Race which failed to climb a wave in a force 7, slid
backwards and capsized over the lee stern.  The masthead float kept
the boat on its side for while, until the mast broke.)  If the boat
gets flipped by a wave, it is very unlikely the the wave will transmit
just barely enough energy to the boat for a capsize without lee pod or
mast head buoyancy.  That little bit of extra capsize resistance would
help for only a small proportion of the spectrum of wave sizes.  If
you are not willing to accept a low probability of flipping the boat
in the first place, I think you have to accept that the boat will go
over all the way and design the boat so that, first, it can survive
this without significant structural damage, and second, so that it can
be righted frum a fully inverted position. 


Robert Biegler

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