Your One-Way Drain Plug

It does exactly what its name suggests.

The one-way drain plug uses a ball-stop that allows tanks to drain and de-pressurize while keeping water out.Dave Navin

From the “how-come-no-one’s-thought-of-this-before?” category comes the one-way drain plug, which does exactly what its name suggests. Especially for boats with forestays, backstays or other control lines running into tanks, it solves the perennial problem of keeping those tanks dry. No more unscrewing drain plugs between races to let water out or, somewhat more risky, leaving them out altogether. “We tried a number of things to let water out of the backbones of our scows,” says Melges President Andy Burdick. “We always thought, ‘Wouldn’t it be great just to have a one-way drain plug?’”

Enter engineers and E Scow sailors Dave Navin and son, Kyle, along with Brian Porter. Together, they developed the patent-pending plug. “I had sketched one up, and Brian built a prototype,” says Dave. Realizing they were working on parallel paths, they teamed up and then got Kyle to do the CAD work. The result was a drain plug with a built-in check valve that uses a small, round ball. Says Dave, “When we first built it, we took a Dixie Cup, cut a hole in the bottom of it, and fit one of the plugs into the hole. It easily drained just a ¼” of water.” Brian has them in his E Scow and says, “It’s remarkable how much drier the boat stays now.” He says they also eliminate the increased pressure in airtight tanks that builds up on hot days.

One-way drain plugs designed for C scow tank drainage and breathing.Courtesy Melges Performance Sailboats

To date, they’ve built around 400 plugs. They sell only the male plug, and their current design fits the standard Sea Dog female housing. Dave says that they will soon be producing plugs to fit other housings, such as RWO and Ronstan.

To install, simply remove the existing plug, screw in the one-way plug, and you won’t have to touch the drain plug again. Be sure to check your class rules to make sure these comply. $40. Available through