Bilge Pumps
This page was last updated on 10 November 2001.

I installed two bilge pumps on board:  a large Henderson MK IV manual diaphragm pump (the same one used by the Lavac toilet) and an electric Rule 2000 GPH with automatic switch.

I began the installation for the automatic pump by installing a three-way switch in the systems panel.  Then, I ran three wires from behind the panel down and through the engine room to the bilge in the main salon, protecting the wires where they run through the engine room by running them through a length of old plastic hose that I had around.  I secured the hose to the engine mounts to keep it in place.  The three wires are for the ground, power supply (+) and automatic switch.  A little later, I will make the connections at the pump according to the supplied wiring diagram.


Next, I chose the position for the pump in the bilge.  #381 has the shallow bilge, so access is easy to all portions.  The lowest point of the bilge is directly beneath the cabin sole between the two access hatches, so I positioned the pump base and secured it with two screws, sealing the holes with polysulfide.  There's plenty of boat and fiberglass beneath the bottom of the bilge so I didn't worry about installing two small screws directly into the glass.  The switch secures to a bracket that snaps into the pump base, a convenient installation that required no additional screws into the hull.  I made sure that the switch had room to move up and down freely.

With the pump installed, I made the final wiring connections according to the supplied wiring diagrams.  There are three wires--a ground (black), the power supply (brown), and a third wire (brown) which leads to the panel light.  I made the connections with waterproof butt connectors, which contain an adhesive that, when heated, melts around the connection, forming a secure, watertight seal inside the connector's heat shrink tubing.  They cost more, but are worth it.  I secured the wires and the protective hose (see above) to the underside of the cabin sole, far out along the hull behind the wooden supports for the bilge access hatches.

I ran the 3/4" discharge hose through the engine room, beneath the fuel tank, and aft to a through hull fitting in the counter.  I fitted a check valve in the line just downstream of the pump to keep the water in the hose from running back into the bilge when the pump shuts off; it's a rather long, uphill hose run, and this amount of water could possibly cause the pump to cycle repeatedly, so I'll take the somewhat reduced discharge rate and use the check valve.

I mounted the Henderson manual pump in the starboard cockpit locker.  Mounting the pump required cutting a large (about 3-4" diameter) hole in the side of the cockpit well, which is always fun.  Then, it was a relatively simple matter of screwing the outside place through the cockpit well and into the back of the pump, which was bilgepumpcover.jpg (24316 bytes)fitted with a supplied conversion ring.  I ran 1-1/2" corrugated hose from a low point in the bilge (just aft of the electric pump), beneath the engine and fuel tank (keeping the hose well clear of the prop shaft, of course) and up to the pump housing.  The discharge line then runs aft to a bilgestrainer1.jpg (62704 bytes) through hull in the counter.  At the suction end, I installed a heavy bronze strainer that holds the hose in place and will prevent any debris from getting sucked into the hose or pump.


To keep the number of through hulls to a minimum, I decided to conjoin the two discharges just above the through hull in the counter.  This required a fairly complex set of fittings, since the hoses are different sizes.  First, I cut the 1-1/2" line and inserted a 1-1/2" plastic "Y" fitting in place.  Then, I connected the other cut end of the line to one side of the "Y".  The 3/4" discharge line from the manual pump required some more work, however.  First, I had to ramp the 3/4" up to a 1-1/8" size through one plastic fitting, then I increased it from 1-1/8" up to 1-1/2" in another fitting just downstream, before connecting that (through a short length of hose) to the other side of the "Y" fitting.  I should have chosen 1-1/8" hose for the manual pump--it's actual discharge size--but I had thought it was 3/4" when I bought the hose and check valve, and they don't make a larger check valve anyway.  This is Rube Goldberg-esque in its silly complexity,  but is constructed and should serve just fine.  Tile will tell, and eventually I'll probably have a better solution at hand.

The bilge pumps are complete and ready for action...although I don't expect any water in the bilges!

UPDATE!  After a season, I have been very happy with the performance of the bilge pumps.  Frankly, I never once used the manual pump, and the automatic pump did its job with no trouble at all.  I keep the bilges very clean, so that helps prevent clogging of the pumps with debris--or, more commonly, clogging the automatic switch.  I never had a problem with this during the first season.  After winter storage the first year, the check valve I installed in the automatic pump discharge failed, so I removed it completely.  Those things simply never work out, but I suppose it was worth a try.

Further updates will be posted as applicable.

Glissando, Pearson  Triton #381

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