Replacing Engine Intake Seacock - Advice Appreciated

[Gary H]

I managed to break my Spartan Seacock on the cooling water engine intake on ny 22D. (I tightened the lock nut without using a spanner to secure the plate cover.). See photo. Sadly, it appears that I have to now replace the seacock ($400 and pull boat from water). Advice on the removal of the old thru-hull and seacock and installation of the new from those who had been through this is much appreciated.

[Jim Walsh]

When I removed and replaced my sink drain seacock during a project to add refrigeration a few years ago I just drove a wood bung into the through-hull so I could have a way to center the pilot drill in my hole saw. If you choose the proper size hole saw you will just drill through the outside flange of the through-hull and you will be able to drive the seacock and remnants of the through-hull up into the boat with the judicious application of an appropriately sized hammer and a tapered steel drift or a hardwood dowel.
It sounds more intimidating than it actually is in practice. In this photo you can see that I had to make a slightly larger hole to accommodate my new through-hull but you may not be required to do so. I ended up with a core sample of my hull and the backing plate.

[Gary H]

Thank you. This is very helpful.
The larger size hole likely makes it easier to drive the old thru-hull up into the boat. I plan on replacing with the same Spartan thru-hole so I imagine I would just use the hole saw to remove the mushroom flange. Hopefully there is not 5200 between the threads and hull/backing plate.

Is that a tapered wood dowel inserted into the thru-hull for the removal?
Thank you.

[Carl Thunberg]

There is a recent topic in the "Project Descriptions" forum entitled "Replacing Spartan Seacock with Groco" You may find some useful information there.

[John Stone]

You should not use a hole saw to remove the through hull. Jim was replacing his through hull with a larger through hull. Good technique for that and suggested by the maker of the hardware he was installing. But not appropriate if replacing with like through hull.

There are two ridges inside the throat of the through hull. You can purchase a through hull remover tool which looks liked a stepped cone or borrow one from a friend. Tap it up intro the through hull and you put a large wrench onto the end of the tool and turn it and it will unscrew from the seacock--as long as the seacock has retaining bolts and it will if properly installed originally. Those bolts keep the seacock from turning plus help hold it tight to the inside of the hull.

Or you a measure the inside diameter of the through hull and goes to Home Depot and by short length of flats steel bar about 1/4" thick. Then file it till it just fits up into the through hull. You want about two inches stick out of the hole with it tapped all the way in. Then put a large pipe wrench on it and turn CCW and it will unscrew. You may need to add a little heat but be careful as you don't want to damage the fiberglass with heat.

This is a simple process. It only requires thick enough steel that won't bend under pressure and a long enough lever arm. Here are links to a post where I documented removing 10 through hulls on my boat.

Technique. http://www.farreachvoyages.com/blank-16/

Tools. http://www.farreachvoyages.com/blank-43/

[Khaos13]

To the OP I would say don't feel too bad about what you did or didn't do. That shaft has the look of "chrystalized" bronze or brass. The black staining indicates it's been there for a while. I've seen brand new propellers throw a blade with exactly this look. I'm not sure what causes it or if it is in the forging of the part itself but it IS a defect in the metal. I've had a Spartan sea cock handle break with the same appearance. I brazed it back together and am much more careful with bronze parts now.