On Sun, 18 Oct 2009 09:21:53 +0200, "Edgar"
wrote:



Vic, if you put auto inflating bags on both gunwhales you will enure that
you will never get her upright again but she will float nice and high while
upside down.

That seems counterintuitive. The gunnel bags would be inflated before
the roll over. If the boat is already turtled or rolling past the
ability of the bag buoyancy to right it when inflated, it would be as
you say. That's a no-no. (-:
But in case you're talking about heavy seas flipping a boat, you're
absolutely right. Bags on the gunnels are worthless.
I was thinking about the more common swamping situations.
Anyway, without thorough testing and an understanding of the
weight/buoyancy dynamics of a particular boat I wouldn't stand by any
contraption I propose.

The Royal National Lifeboat Institution in Uk used to have boats that were
inherently self righting but such a boat does tend to turn over more often
than necessary which is a pain even if it rights itself afterwards.
Modern lifeboats are not inherently self righting but instead have an
automaically inflating buoyancy bag which is centrally mounted in the
superstructure so it exerts maximum righting leverage whichever way she
turns over.

That's similar to the masthead bags for sailboats. Then the problem
becomes righting the boat from a laid down position.
I was thinking that a good system for an open boat would prevent the
capsize due to swamping, and leave only the bailing.
No need to go outside the gunnels.
But on that subject of righting, my recollection of righting small
boats is that once one gunnel is free of the water, the rest of it
goes pretty easy as that side lightens right up as water leaves it.
Then the only issues left are not to let inertia roll it again on the
other side, and getting it bailed out.
The boats I righted always had me standing on the bottom, so muscles
can be well-used.
Totally different than doing it while afloat, which from what I've
seen is darn near impossible without motor power, unless it's a very
light weight boat, even with a crew of strong men.
If I were in the business of righting small boats, I'd carry a rig to
make an A-frame over a capsized hull to get some leverage.
Maybe 10-12 foot scaffolding type tubes. One side has a hook to go
over the offside gunnel, one side a clamp for the nearside gunnel on a
u-joint. Both are joined at the apex, where a line is attached.
Should make it a lot easier to roll the boat back over pulling on the
nearside, whether with a power boat or men in the water.
Man, I wish I lived by that warm Florida water where I could monkey
around with this stuff. That would be fun. If the fishing is slow,
go play with turtled boats.

--Vic