Bilge Pump Discharge - New Thru Hull ??? - SailNet Community
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post #1 of 4 Old 04-30-2003 Thread Starter
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Bilge Pump Discharge - New Thru Hull ???

Hi Everyone,
Looking for some advise on installing an electric bilge pump in my sailboat. Do I have to install a new thru hull fitting or is it possible to connect the new bilge pump discharge line (3/4") into a "Y" connection that would be installed in the existing (1 1/2") manual bilge pump discharge line ... aft of the manual pump itself ???
Any advise would greatly be appreciated.

Thank you,
Terry Clarke
CAPTIVA, Port Whitby
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post #2 of 4 Old 05-01-2003
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Bilge Pump Discharge - New Thru Hull ???

Expect you''ll get some contrary advice, but:
If your intent is to add an automatic bilge pump, for use when boat untended - your idea has merit.
There''s, obviously a trade-off here. You''ll still only have one pump available (at a time), and would want to ensure that the diverter ("Y") valve is quickly accessable, and preferably c/w mounting feet/flanges (fasten to bulkhead or whatever). Ensure that you don''t "foul" the discharge (vented) loop, and adapt from the .75" pump discharge to the 1.5" overboard discharge as early as possible. NO CHECK VALVES!
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post #3 of 4 Old 05-01-2003
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Bilge Pump Discharge - New Thru Hull ???

You do not stae the size of the vessel but a 3/4 line for a bilge pump is very small. These are normally 1-1/2 in diameter. Once you run this hose to the aft end of your boat, depending on its size, you will have a lot of water in the hose. I would definitely put a check valve in-line so the pump is not cycling all the time. You could easily have a half to full gallon of water in the line depending on the depth of the bilge. Don''t forget you have to run the discharge hose high enough in the boat to prevent back siphoning when heeled over. Yes to Czech valves! Why cut corners by sharing a through hull? It should be a dedicated line, your life could depend on it!
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post #4 of 4 Old 05-01-2003
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Bilge Pump Discharge - New Thru Hull ???

Run separate, properly sized hoses for each pump. The single line theory is good until it gets knocked off or screwed up at the end toward the thru hull. Then all pumps on the line are useless. Redundancy, donchaknow. I put a Rule 360gph automatic at the bottom of my 5'' bilge. 8" higher I put a manually switched 1500 gph. There''s also a whale gusher, each on separate lines. Skip the Rule float switches. They seem to go to crap on a regular basis, even the more expensive "waterproof" ones. The 360 auto I have (I don''t know if they make it any more - they might only have the 500) draws very little amperage and has done so since 1994. The float switch problem I''ve noticed more and more after moving to the Caribbean and replacing switch after switch on friend''s boats. Further, hoses and bilge spooge and spooey can lay across the things and keep them from activating. KW
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