Subject: [harryproa] Re: mast bouyancy
From: "Robert" <>
Date: 2/6/2006, 9:02 PM

Hi Carlos,
My own experience with lots of capsizes in small boats and
windsurfers is that the sail damps the initial rotation and then if
you don't uncleat you have a hard time of it getting it back as it
tends to hold onto the water pretty hard. I have seen bouyant panels
sewn into the tops of dinghy sails and they seem to work to avoid
turning over completely. Theoretically it should work on a bigger
boat but scaling up often brings suprises. I am assuming a capsize
from carrying too much sail in pretty strong winds such as one does
when racing. On the other hand a racing boat would have a taller mast
and therefore more mast bouyancy set higher, while a cruising boat is
extremely unlikely to go over.  I have seen the bouys on the top of 
masts but have no idea of the cons. Is the extra windage that much of
a problem or not?. I think i see your point of the possibility of the
sail scoopin water as the boat is blown down wind. Rob's experience
on elementarry is the boat quickly spins around, but that is on the
smaller lightweight versions. Uncleated there should be no problem
and a bouyant top panel should also avoid this problem,

--- In, carlos Solanilla
<carlosproacarlos@y...> wrote:
> Hi Rob
>   I do not have experience with the bouy at the top mast but I
wonder how much a cleated sail in the water acts as a fulcrum to
force the mast to go under as it gets filled with water
> Robert <cateran1949@y...> wrote:
>   Did some rough calculations on the Harryproas stability at 90
> Empty, a Harry is stable on its side but not by a large margin.
> Probably the resistance of the masts as well as the bouyancy would
> it turning over. Loaded, IFF the loads are well placed the
> improves. An extra 40kg or so bouyancy at the masthead and there is
> improvement. Possibly soft urethane foam sewn ito the top panel of
> sail would do. With wing masts the margin is much larger.
> Regards
> Robert
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