The scale of Biscuit's refit will include a much needed reboot of the thru-hulls, and today's focus was on the cockpit drain thru-hulls. These skin-fittings, and working plumbing components on the interior side of the hull, are most often necessary in order to rid the boat of unwanted fluids - fluids that range on the scale of clean and innocuous freshwater to the diabolic and malodorous effluent of some gray or blackwater tank! These skin-fitting, and their interior counterparts, or seacocks not only rid the boat of unwanted fluids, but should also work to keep the body of water within which the boat resides out.

Biscuit's two seacocks and skin-fittings (thru-hulls) for her cockpit drains were in fairly good shape - exhibiting only surface patina of the sort that regularly adorns bronze alloy. The issue that concerned me was not the integrity of the bronze alloy sentinels, but the type of seacocks chose for installation just below the cockpit and just aft of the companionway. As can be seen in the photos below, the seacocks were of the simply gate valve sort, and importantly lacked a flange at the base to protect thru-hull from damage - damage that could lead to water ingress and the sinking of the boat. On the interior of the boat, the threads of the thru-hull fittings were visible, and just above those visible threads was the gate valve seacock. An accurate and forceful enough impact onto the seacock could sever the connection and lead to a hole in the boat. So, as can be seen below, Biscuit will receive an upgrade in selection of the seacock - that interior portion of the thru-hull combo - when the new skin-fittings are installed.

The location of the existing thru-hulls and seacocks - tight up against a molded interior stringer - would make installation of the new flanged seacocks all but impossible. The best course of action was to remove the thru-hulls and glass-in the holes, thereby creating a blank canvas on which to select the new and workable locations for Biscuit's new thru-hull and seacock assemblies.

I began by cutting the thru-hulls with an oscillating tool, partitioning the circular collar into several parts and just coming into contact with the fiberglass hull. Once this was accomplished, I used a flathead screwdriver and a hammer to coax the individual portions of the collar up and away from the hull, eventually snapping off of the thru-hull itself. With the collar removed in its entirety, I then hammered what was left of the thru-hull into the boat, exposing the actual hole in the fiberglass hull.

Repairing holes in fiberglass necessitates a patch with a diameter roughly 12x the thickness of the fiberglass itself, or 12 to 1 bevel. In the case of Biscuit's turn of the bilge, she was approximately 1/4" to 3/8" thick, and so required a tapered to be ground 3" from the penetration, creating patch area roughly 6" in diameter. I marked the area to be ground with a Sharpie, and then set to work with an angle grinder and a 40-grit flap disk. Checking occasionally with a straightedge, I snuck up on the properly prepared surface removing a bit here and bit there until satisfied. While working with the grinder, I identified areas of the bottom that exhibited deamination and ground those areas out as prep for repair as well. I did observe a few voids that required filling, so prior to knocking off for the day I applied thickened epoxy to those voids in preparation for laying up the fiberglass lamination and bringing the hull back to that blank canvas condition.

Total Hrs: 4.5