Last weeks post detailed the start of the installation of the new Forespar Marelon seacock for our engine raw water intake. Picking up where we left off, I cleaned up all the old sealant that was left under the old rotten wood base and I sanded down the entire area. Since the new wood base is substantially larger than the old I made sure to sand out a good distance around the hole in the hull. It is really important to have a clean, raw fiberglass surface for the epoxy to adhere to. The last thing we want is be doing some maintenance on our bilge pumps and fall on this seacock one day out in the middle of the ocean to have it crack off and have water flood in!
Once everything was sanded down well enough, I found a cut away piece of oakum that I had been saving for such a project and traced out the seacock base. I then measured out from the outline of where the seacock will be and cut the wood into a round shape, roughly matching the contour of the seacock. Its not necessary to match the contour, a lot of pre-fab seacock bases are perfectly round, however, I like to think that it would help disperse the load a little bit better in a high stress situation.
I then held up the wood to the hole in the hull to see if my sanded area was wide enough and would work well.
For this small of a seacock we used 1/4 inch X 20 silicon bronze bolts and their corresponding nuts. After counterboring the underside of the wood I threaded the bolts through and fully tightened the bolts, pulling them into the wood and recessing their curved undersides so there are no point loaded parts touching the hull.
Mixing up a batch of unthickened epoxy, I gave the wood several thick coats to protect it and prevent any chance of rot one day in the future. A friend recently asked me why I am using wood at all – wouldn’t it just rot again? It’s a great question and brings up a great point. I am only using wood because its free, I already have scraps of great boatbuilding wood laying around, its easy to work with, and properly coated in epoxy it will not rot. The “properly coated in epoxy” part is important and several coats really need to be laid down to protect the wood. An alternative would have been G10 or fiberglass bases. These two are excellent seacock bases and I do not know of a reason not to use them. However, they aren’t cheap and I don’t have any laying around. The custom wood bases I’m building are oversized, perfectly match my needs, allow the silicon bronze bolts to pull in and bond with the wood, and don’t cost me more than the couple coats of epoxy that I lay down to protect them. The thriftier we are, the faster we sail. I would absolutely never cut corners on this boat – as many of you know she is overbuilt to begin with and every project that I do is ratcheting us up into a new dimension of tank-like over preparedness. However, there are many ways to save money and I hope we are taking advantage of all of them! 🙂
I let the wood cook out in the sun while I tackled some other side projects I have going on. Once finished, I sanded down the underside and wiped it down with acetone to prep it for adhesion.
With the wood fully prepped, I mixed up a big batch of epoxy thickened with 407 high density and 406 colloidal silica adhesive fillers. I mixed this batch thick, almost like the creamy fake peanut butter with all the sugar in it that I used to love as a kid. If you still eat that stuff please stop – your just consuming a bunch of sugar! haha – go get yourself some natural peanut butter and do that bit of work to stir it up, its like a hand and lower arm workout and healthy choice all bundled into one! 😉 Anyhow, back to the epoxy – it had to be thick since we are installing this seacock on a curved part of the bilge. Why they decided to drill the hole here is beyond me but we can work with it. Once mixed up, I laid the epoxy down with a big popsicle stick and then mushed the wood base in place, pushing down hard and making sure there were no bubbles on the underside. I then filleted the epoxy that squeezed out around the sides making a nice contour around the base.
Once complete, I let it set up for a while while I held everything in place and then put the new seacock in place. I then threaded the thru hull into the seacock from the outside of the boat and I’m happy to say everything looks like its going to work out very well. 🙂