Attaching Seacock Backing Plates

Marelon Flanged Seacock

On May 9th, 2010, I took the opportunity (after prepping the topsides for a coat of primer) to 'glue' in the new seacock backing plates. I decided to go ahead and use wood backing plates for these seacock installation, after mulling over creating my own fiberglass plates by building up layer upon layer of fiberglass wetted out with epoxy. The downside to the wood installation is potential future water seepage and subsequent breakdown of the plate. To guard against this, I coated all pieces of my constructed plates with epoxy prior to assembly.

The plates are made of red oak, 1/4" thickness. For each backing plate, I cut 3 squares approximately 4" x 4", sanded all surfaces, solvent washed them, and then coated all surfaces of each piece with epoxy. Once the epoxy had cured, I sanded to create a good surface for mechanical bonding, mixed up epoxy thickened with West System 403 Microfibers (great as a filler and for wood bonding), spread this thickened epoxy on the oak squares, and finally carefully clamped the pieces together while the plate cured. Once the plate had cured, I cleaned up the excess epoxy that had oozed from the assembly, and generally cleaned and rounded the edges. On to the hull...

On the interior of Froonie's hull, I sanded the surfaces to where the backing plates would be attached, and generally prepared the surface for epoxy work. Again I used the 403 Microfibers, mixing enough to generously fill any uneven surfaces and/or small voids on the surface of the hull. I spread this thickened recipe onto both the underside of the backing plate as well as onto the surface of the hull itself. I then firmly set the backing plates into position making sure a bit of filler oozed from the edges. Finally, I formed a fillet around the base of the backing plate for possible cloth application later on, or at least to create a smooth transition that would appear visually pleasing.

Here is a picture of one of the original thru hulls after I had extracted it. The factory set up was essentially a thru hull glued in place, with a locking nut set tight against the interior of the hull. The hose for draining the cockpit scupper was then attached directly to this thru hull. One accidental kick of this thru hull could open up the flood gates...so I am taking the time to install proper flanged seacocks and thru hulls (see pic above of the Marelon seacock). There are two cockpit scuppers, and so therefore two seacocks.