BoatBanter.com - View Single Post - Tapered thread thru-hulls ?

(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.