Engine Room Seacock II

In the last post about the engine room seacock I made the copper fitting that connects the port side deck scupper drain hose with the port cockpit scupper drain hose.  At this point the new Groco seacock we purchased was still dry fit and free floating on the insufficiently small, old, rotten wood ring that the old ball valve threaded down on.  To remedy this I started by grabbing some of the okoume wood left over from our inner forestay bulkhead.  I cut this wood down to an appropriate size for the seacock and cut it into shape.  I then sanded it down, rounding out all of the corners so there would be no sharp edges.

I then removed the dry fit seacock and un threaded the lock nut that was on the thru hull.


At this point I used a pair of vise grips clamped onto a wrench to thread the thru hull out of the boat.  Once the thru hull was out of the way I used a painters multi tool and a hammer to strip away the rotten wood ring.

With the little wood ring out of the way I was free to prepare the surface for the new okoume seacock base.  I had to strip away layers of paint, primer, and assorted sealants that had dried up in this area over the years.  The whole area around here was really rough and had some quick and dirty fiberglass work done to it so I ended up sanding down a lot of that as well.  It was a challenge to sand only the “high” areas and paints without thinning out the fiberglass of the hull.  I had to concentrate very hard on the angle of the sander to ensure that I was only removing material that needed to be removed.


After cleaning the newly sanded area with acetone I turned my attention back to the okoume.  Using the seacock and thru hull as a template I traced out the holes that would need to be cut for the thru hull and silicon bronze bolts.

Once everything was traced and centered I cut the hole in the middle out with a hole saw.  I then rummaged around in the fasteners organizer bin to find our 3/8″ silicon bronze bolts and nuts.

I then used a 3/8″ drill bit to drill the holes for the bolts and dry fit the seacock.  The bolts are carriage bolts so as you tighten them down they press into the wood and hold themselves in place.  They also have a rounded head that pulls into the wood and does not protrude out aggressively.  For our purposes, however, I really wanted them to be flush, so I countersunk them a small amount as well.


Once the wood was fully formed I mixed up a batch of un-thickened epoxy and gave it one coat all around.  This waterproofs the wood more or less and it is particularly important on the edges to seal up the end grain so that it doesn’t suck up moisture.

I then applied a layer of un-thickened epoxy down to the cleaned hull surface where the wood was to be mounted.  At this point I mixed up a big batch of epoxy thickened with 404 high density adhesive filler.  404 is a very high strength filler that is very dense and is good for this type of thing.  406 Colloidal Silica could also have worked in this scenario, and I did add a little in, however I find that 406 is much harder to mix without getting dry pockets and for this I wanted to avoid those at all costs.

Once the epoxy set up and hardened I was able to drop the seacock on to the bolts.  I then went outside and used my wrench/vise grip tool to thread the thru hull into the seacock.   At this point I went back into the boat and tightened down the silicon bronze nuts onto the bolts and re-connected the hoses.

And here is a picture of the final product!  I am still waiting on my new hose to arrive for the side deck scupper and I think I will make the hose you see here a little bit longer but things are really starting to look good.  A nice coat of bilge paint and this whole area will really shine.  I’m quite happy with how things have turned out and feel 100 times better about the strength and long term reliability of this set up.


2 thoughts on “Engine Room Seacock II

  1. Nice work Ryan! Question: how will you finish the external hull area around the thru hull? Right now it almost looks like the threaded thru hull mushroom base is resting up on very little hull fiberglass (when viewed from below, as in the second small picture at the bottom of this post). Will you be adding the fiberglass to the outside at a later stage? Will there be sealant around the threaded thru hull and finally, when done, will the mushroom base be proud of the hull or fiberglassed over?

    Liked by 2 people

    1. Michael, Thank you! The fiberglass is a bit thin there so that when the thru-hull is tightened down it is more or less flush with the rest of the hull. The compression of the thru-hull and the bronze that it is made out of compensates for the slightly recessed fiberglass. That said, I noticed that this area could use some work so I will be adding some epoxy and fairing the area to ensure that everything is 100% as far as strength and integrity go. There will be sealant around the threaded thru hull as well, both on the threads and on the mushroom head of the thru-hull. When complete, it will not be 100% flush but it will not stick out much either. The thru-hull will not be fiberglassed over – there is no need for this and it would also make it difficult to inspect and difficult to pull out if needed. I hope that helps! I am going to try to get to this part of the project before the end of the year so you should seem some upcoming blog posts on this topic specifically 🙂

      Liked by 1 person

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