Comments below:
"Trent D. Sanders" wrote in message
om...
Not sure I understand your reply,,, do you mean to say that tapered
[pipe] threads wouldn't "snug down" like straight threads? Seems like
when I do plumbing around the house that that's the case.

Maybe I should have asked the question of whether anyone makes a
straight threaded ball valve.

Trent
S/V Cimba

I'll try to explain what he meant. As you know tapered threads are tapered.
They are used for pipe fittings because as they are screwed together the
tapers come closer and closer together until all the space between the
threads is taken up and the fitting becomes tight. The threaded area can
only be so long as it tapers at a constant rate. If you tried to make a
tapered thread thru hull it wouldn't work because the threads at the top
would be way too loose and weak with not enough thread contact, and at the
bottom too tight for the ring to turn far enough to hold the thru hull tight
to the hull.

Make sense? You could probably get a plumber to re-cut the straight threads
into tapered threads on the top of your thru hulls but it would be better to
use real seacocks with regular thruhulls threaded straight in as explained
in an earlier post.
--
Ken Heaton & Anne Tobin
Cape Breton Island, Canada
kenheaton AT ess wye dee DOT eastlink DOT ca

Not sure I understand your reply,,, do you mean to say that tapered
[pipe] threads wouldn't "snug down" like straight threads? Seems like
when I do plumbing around the house that that's the case.

Maybe I should have asked the question of whether anyone makes a
straight threaded ball valve.

Trent
S/V Cimba

(John) wrote in message . com...
(Trent D. Sanders) wrote in message . com...
Does anyone know of a source for BRONZE tapered thread [pipe thread]
thru-hulls?

The thru-hulls sold by Worst Marine and others are all "straight
thread" with straight thread tightening nuts. The sea-cocks that go
on these thru-hulls are also straigh threaded, but are designed to be
bolted [ usually 3 bolts ] through the hull also. It would seem that
for a fiberglass hull the less holes the better.

So many people put a tapered thread ball valve [seems like all ball
valves are tapered threaded] on to the straight thread thru-hull. Not
a good idea.

T. Sanders
S/V Cimba

The reason you can't find a tapered thread on a thru-hull is because
you don't want tapered threads on a thru-hull. The standard nut on a
thru-hull guarentees that the nut is holding the back of the face of
the thru-hull tight to the hull, the same holde true with the backing
material and nut. Exerting a clamping force on the thru-hull, giving
you a good seal to the hull. The problem with the tapered design would
be that the nut, which might be tight, would be tight to the thru-hull
threads, but may not be exerting any clamping force on the thru-hull
face. The nut could be nice and tight, and the thru-hull might be
loose to the hull.

(Trent D. Sanders) wrote in message . com...
Does anyone know of a source for BRONZE tapered thread [pipe thread]
thru-hulls?

The thru-hulls sold by Worst Marine and others are all "straight
thread" with straight thread tightening nuts. The sea-cocks that go
on these thru-hulls are also straigh threaded, but are designed to be
bolted [ usually 3 bolts ] through the hull also. It would seem that
for a fiberglass hull the less holes the better.

So many people put a tapered thread ball valve [seems like all ball
valves are tapered threaded] on to the straight thread thru-hull. Not
a good idea.

T. Sanders
S/V Cimba

The reason you can't find a tapered thread on a thru-hull is because
you don't want tapered threads on a thru-hull. The standard nut on a
thru-hull guarentees that the nut is holding the back of the face of
the thru-hull tight to the hull, the same holde true with the backing
material and nut. Exerting a clamping force on the thru-hull, giving
you a good seal to the hull. The problem with the tapered design would
be that the nut, which might be tight, would be tight to the thru-hull
threads, but may not be exerting any clamping force on the thru-hull
face. The nut could be nice and tight, and the thru-hull might be
loose to the hull.