Hi. Please read post 7 by Captain
J. and watch the proper way to do seacocks.
One of the most common mistakes
is confusing threads because this can be very dangerous. Straight thread should never be inserted into tapered fittings. You can sometimes get a few threads together but there is no real support and the application of some type of sealant
is just going to hide a problem. They are not designed to go together...period.
Here is how to tell the difference.
Thruhulls are usually straight thread. You have a nut which screws along the thread like a nut and bolt. Lay two rulers or a flat surface and a ruler along the threads opposit one another. You will see the edges are parallel.
Now take a pipe nipple and do the same. You can see the edges converging or tapering. In female tapered fittings, itís a little more difficult to see, but itís there. Tapered fittings are designed to lock together to prevent leaks
Application. Groco adaptor plates have both. The female side is straight thread.
This faces the ocean and is designed to take a thru hull with straight threads.
The male inside is tapered so you can use any ball valve or pipe fitting with the usual tapered threads.
Real seacocks...seacocks that are attached to the hull...will have straight threads for the thruhull and tapered for fittings inside the boat.
Lastly, I have examined hundreds of seacocks. I recently looked at all the Apollo bronze seacocks which were in a boat I built 40 years ago and they looked and worked perfectly. I have never seen a real bronze seacock corrode unless it was bonded to an electrical system
with real problems. In this one case, the corrosion
was limited to the stem bolt and handle.
Tru Design, Forespar and other supported valves rely on the integrity of the thruhull. If the exterior head
of the thruhull is damaged by an object, ice or a reef the valve will loose this integrity. You will wish it snaps off cleanly so you can plug
the hole. If itís just loose, itís vey difficult to stop the water
With a proper seacock, you can remove the thruhull, grind off the mushroom head and it will still keep the sea out.
Supported valves are cheap
to buy and fast to install. Well till later...
Happy trails to you.
Mark, a boatbuilding manatee