Seacock and Thru Hull Installation

Sunday afternoon, September 12th, I arrived back at Froonie and set things up for sanding the fairing filler I applied the previous evening. The first coat of deck primer (Interlux Epoxy Primekote) presented a number of areas that needed to be filled and faired prior to continuing on with subsequent coats.

I water washed all areas that I filled to remove the amine blush, using a 3M scouring pad. Next, I set up my DeWalt vs random orbital sander with 150 grit hook and loop pads and carefully sanded the surfaces to fair. I went back and hit the tighter areas by hand, areas that the machine would prove too aggressive with. The filler material I used is West System Epoxy with a mixture of 406 colloidal silica and 407 low-density filler (micro-balloons). Here is the photo of the foredeck after I completed all sanding of the filler.

Once the sanding was complete, I wiped down the topsides and deck with solvent to remove residual sanding dust - just to keep things relatively tidy. I then moved on to the day's primary task: installation of the thru hulls and seacocks.

First thing that I did was to lay out all required components, and mentally go through the exercise of installation. I decided to use Marelon thru hull fittings and seacocks; my decision was based in part on price, but mostly on the anti-corrosive nature of the product and its durability. I used SitkaFlex 291 for the bedding compound (liberal amounts), and silicone bronze flat-head machine screws, washer and bolts.

The seacock bases are made from three 1/4" squares of red oak laminated with epoxy - bedded onto thickened epoxy, with fillets created around all sides. The use of red oak was not the best choice, and future bases will be installed using fiberglass board (G10, or the like, or my own hand-laid fiberglass boards). I will no doubt be checking the integrity of the bases and seacocks for the first 2 years she's in the water...

After installing the bases and drilling for the screws and thru hull fittings, I came back and counter-sinked all screw and thru hull openings (except for the hull side opening for the thru hull). This counter-sinked area around each opening would provide further space for the bedding compound to migrate to, providing a good barrier between ocean and boat interior.

PROCESS:

1. I applied bedding compound to the screw heads and their exterior counter-sinked entry holes

2. I partially inserted screws into holes

3. From inside, I applied bedding compound to the counter-sinked openings on the seacock base plate

4. From inside, I applied bedding compound to the underside of the seacock base and placed on the screws

5. I tightened down the seacock base , and wiped away much of the oozing bedding compound

6. I wrapped plumbers tape around about half of the threads of the thru hull fitting

7. I gooped-up much of the interior of the thru hull hole, and screwed the thru hull into the seacock base

8. I wiped up the oozing bedding compound for a tidy appearance

9. I repeated for the other installation

Photo below shows the installed seacock base, and silicone bronze screws tightened down.

Next, I cut the bronze machine screws to appropriate length, and secured the balance of the seacock assembly.

This photo, below, shows the thru hull fitting installed - starboard cockpit scupper drain. After cure time, I will apply fairing filler to screws holes to bring to fair and further protect against water intrusion.

This photo, below, shows the thru hull fitting installed - port cockpit scupper drain. After cure time, I will apply fairing filler to screws holes to bring to fair and further protect against water intrusion.