Draining the Deck Swamp

Draining the Swamps

By Lee Thurner
Meridian, Sloop no. 139

One of the minor annoyances that detract from our otherwise wonderful boats is the puddles of water that won’t drain from the side decks, owing to the placement of the scuppers forward and aft of the low point. Those puddles are in exactly the wrong places…right at the boarding gates…and they seem to accumulate the everyday detritus that lands on the boat and present it to the crew every time they step aboard.

After thirteen years of living with these “swamps” I finally eliminated them with a project based on an idea I saw in Bruce Bingham’s Sailor’s Sketchbook.

The solution consists of adding a small scupper that has an opening flush with the deck, and then routing the water it collects outside of the boat.

Getting the water off the deck

Unsuccessful in finding flush through-hull fittings small enough for this application, I adapted Bingham’s idea and bought a pair of bronze hose adapters that had a ¾” hose barb at one end and a ¾” male tapered pipe thread at the other. I preferred not to have the ends of these adapters showing at deck level, so I installed them as shown in the drawing and described below:

Located the low point of the deck…the point at which the “swamp” is deepest…and measured and marked its location with reference to a point that can be found below. In my case the reference point was the forward outboard bolt of the farthest-aft stanchion base. The farther outboard on the deck that you locate the scupper, the better the swamp will drain.
Back below, found the spot and made sure it was unobstructed by wiring or plumbing. I had to relocate the wire chase to clear it. Also made sure that the balsa core of the deck spanned the scupper location.
Back on deck, drilled a 1/8” pilot hole at the center of the scupper location.
Back below, with the pilot hole as a center, used a 1” hole saw to cut a hole through the inner fiberglass skin and the balsa core, but not through the deck skin laminate.
Back on deck, used a ¾” hole saw to make a hole in the deck skin.
Back below (tired already) and cut screw threads into the deck core by screwing the threaded end of the hose adapter into the 1” hole, turning it with a wrench. The size of the ¾” fitting gives it an almost perfect fit in the 1” hole. Removed it and applied a liberal coat of 3M 5200 sealant to the inside of the hole in the deck (to seal the deck core) and to the threads of the hose adapter, and screwed the adapter into place. Snug it up against the deck skin but don’t over tighten it. Smeared some more 5200 around the joint where the fitting penetrated the inner skin; allowed the 5200 to set up before proceeding.

Getting rid of the water

There are several ways to route the water collected by the new scupper to the outside of the boat. The most obvious, and probably the easiest, is simply to add a ¾” through-hull fitting below the new scupper and connect it to the scupper with hose. I didn’t want black streaks down the hull, and anyway preferred not to make any more holes in the hull, so I opted to tee into the existing hoses that drain the aft scuppers. I found suitable

1 ½” x 1 ½” x ¾” glass-reinforced nylon barbed tee fittings at a marine surplus store and, using a 1 ¼” hole saw, routed the ¾” scupper hose through the furniture and bulkheads, keeping appropriate slopes for drainage; cut the 1 ½” hose, and installed the tees with hose clamps.

Result

The new scupper drains all but about a tablespoonful of water from the deck, and that small amount evaporates quickly.

Caveats

Those who have the “A” plan may not be able to reach the aft scupper hose without exposing the new hose to view behind the chart table. In this case the hose can be routed between the shower molding and the hull, albeit with a little more trouble, to reach the forward scupper drain hose at a lower point. I have added a panel in the navigation station that hides this part of the hull, so I didn’t have this problem.

If the balsa core doesn’t cover the proposed scupper location, the thickness of the deck laminate should be supplemented to give adequate “bite” for the hose adapter threads. A few additional layers of glass mat and resin should accomplish this, but it will also make forming the threads more difficult. An alternative solution would be to install the fitting and then encase the penetration in Marinetex or a similar solid epoxy.