Building Hand Bilge Pumps

I read Dave Carnell's page on building PVC bilge pumps for sailboats, so I decided to build one like the kayak-sized Beckson pumps.

The pumps are made from:

First, cut a disc of plastic the exact diameter of the inside of the pipe. This will be the bottom plate. Then, cut a disc about 3/8" smaller than the pipe ID, and a second disc about 5/8" smaller for the top plates. Drill a series of holes or slots in the bottom plate for water to enter. The holes should stop about 1/8" from the outside of the disc so there is enough surface area for the bottom flap to seal.

Drill a 1 1/4" hole in the side of the 2" pipe, about 3" from the end. Rough up the area around the hole and one end of the 3" pipe. Glue the 3" piece in with a fillet some well-thickened epoxy. When the epoxy cures, use a round file to smooth off the end of the 1" pipe that protrudes into the 2" pipe.

With some of the same epoxy from the tube-gluing operation, fill the 1/2" PVC pipe about half-full. When the epoxy cures, drill a 13/64" hole in the center of this thickened epoxy. Don't drill all the way through the top of your epoxy pour so epoxy won't drip down into the hole when you glue in the dowel. Tap this hole with a 1/4" UNC thread. Glue one end of the dowel into the open end of the 1/2" CPVC. Coat the dowel with unthickened epoxy.

If you've used a holesaw to cut your discs, then they already have a hole in the center; if not, drill a 1/4" hole in the center of both top plates.

Cut a disc of inner-tube about 1/16" larger than the ID of the pipe. Sandwich it between the top plates, with the smaller plate against the 1/2" pipe. Bolt the stack to the threaded hole with a 1/4" x 1" stainless bolt.

Cut a disc of inner-tube about 1/8" smaller than the ID of the pipe. Use a small stainless machine screw, fender washer, and locknut to bolt the bottom flange to the bottom plate.

Slide the bottom plate into the bottom of the pipe so that it sits about 1/8" inside the edge of the pipe. Drill 3 holes, evenly spaced around the perimeter of the bottom of the pipe, about 1/4" from the bottom and into the plastic plate. Screw the pipe to the plate with (3) #6 x 1/3" stainless machine screws.

Drill a 1/2" hole in the center of the PVC cap. Slip the dowel through the hole in the cap (threaded end inside) and glue on a 1/2" piece of 1/2" CPVC to the other end of the dowel.

Force-fit the cap onto the PVC pipe rather than screwing it on. This way you can smack it with a stick or a rock on the beach if you need to take it apart for field servicing! I am not saying that this pump design will immediately need field servicing, but my friend, Pump Guru Pete Roszyk advised me that ALL pumps will eventually need servicing!

Glue the 1/2" tee onto the CPVC on the end of the dowel. Use contact cement to glue a 4-5" piece of one of those hollow pool noodles onto the pump for a float; and voila! your own bilge pump.

Bruce Anderson made some PVC bilge pumps with some nice improvements.

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