On Fri, 28 Oct 2005 07:46:14 -0700, Robert or Karen Swarts wrote:

This is not an original idea with me. I have seen it recommended in a couple
of articles/books on deep water sailing/boats. There is no disputing the
math, although other factors do come into it.

BS


Well, there have been many bad ideas published over the years, I'm sure.

But anyway, a mast filled with air and submerged will have more buoyancy
than one filled with water. And that buoyancy will, all things considered,
have a tendency to right the boat. I don't dispute that at all.

I am just asking the question "What effect is there on the chances of
righting your boat when your 'sealed' mast fills up with water which then
can't easily escape?"

Because I fear that the mast may stay submerged long enough to fill up.
Anyway, I don't think I have anything new to say on the subject.

Maybe you could put flapper valves on the mast so water can't come in, but
can get out at the mast head, and air can't get out but can get in at the
mast's base?

;-)

--Mac


"Mac" wrote in message
news
On Thu, 27 Oct 2005 16:22:26 -0700, Robert or Karen Swarts wrote:

Let us suppose the mast is 4" in diameter and 25 ft long, stepped 4 ft
above
waterline. The weight of water it displaces is 138 lb. Let us suppose
half
if that is the weight of the mast. That leaves 69 lb positive buoyancy.
The
center of buoyancy of the mast is about 16 ft above waterline. That will
create a righting moment of about 1100 ft lb when the boat is flat on the
water. That is not inconsequential, and could be a large help in
preventing
a total capsize.

BS

[snip]

This all seems very doubtful. I am not sure if you understand how dynamic
the sea-state is in conditions likely to cause a knockdown in the first
place.

Maybe you should ask a real naval architect (marine engineer) about
this. I think it is a very bad idea which you will regret if you do it,
but I am not an expert.

--Mac