"Dave" wrote in message
...
On Thu, 10 May 2007 14:55:37 GMT, "James"
said:

Since thru-the-hulls have straight pipe threads and the ball valves
have tapered pipe threads I don't see how this is possible. Am I
missing something?

Coupla things.

West has some ball valves that will fit right onto the straight threads of
the thru-hull.

However for purists, that setup will run into the objection that the
thru-hull may break as the result of galvanic corrosion when you try to
close the ball valve. Current standards call for a flanged connection.

(Not being that much of a purist, I replaced my gate valves this season
with
ball valves that screw onto the existing thru-hulls. The existing
thru-hull
has held up for 25 years, so I'm not too concerned about it.)

One point, Dave: All through-hulls have a limited lifespan. Essie also
has/had threaded through-hulls onto which seacocks are screwed, but I'm in
the process of eliminating them. In a salt environment, Essie's
through-hulls lasted 40 years. She is now in fresh water, and they still
look and feel solid, but I do not consider that to be a permanent state.

So far I have completely eliminated three of these through-hulls (head
compartment), glassing them out and converting to a porta-potti setup, with
the head sink discharge now being pumped out well above heeled waterline.
Eventually I will eliminate EVERY below-water through-hull that I can.
Ideally, I will have only two: seawater intake for the engine, seawater
intake for the galley sink. But it's an unknown at this time whether or not
I can get my cockpit drains to discharge above waterline.