siphon problem

[budkarins]

The outlet for the bilge pump on my C Morgan 38 is very close to
the waterline. With 3 or 4 people in the cockpit and under
power, seawater siphons back through the bilge pump hose into
the bilge. I put a shut-off valve in the line but am
uncomfortable with the valve in the off position if I need to
pump the bilge quickly.
Has anyone else found this problem and if so I need sugestions
as to how you solved it.

 

[aistqm]

Bob. Is there enough room to place a high loop (up to the under side of deck - a'la exhaust hose) on the sea side of the pump.

 

[jhask]

<div>Bob,On my 382 there is a high loop on the starboard side inside the engine compartment. It uses a vacuum breaker to avoid the siphon problem. Several years ago the breaker became clogged and I experienced the same problem.Somehow I always thought that this was the way the boat was designed. If you have a high loop you may want to replace the breaker. In fact I need to replace the one on my head discharge loop. I redid my head hoses a couple of weeks ago and noted it was clogged.Dick
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[barefoot]

Bob -- I didn't have that problem, but the long run of hose up from the bilge pump led to significant amounts of water coming back into the bilge when the auto switch turned the pump off -- it was half way back to the turn-on point. So I installed a one-way valve in the hose as it goes up through the engine compartment. Water can go out but not back in. That helped with my problem and I think it would solve yours.

 

[budkarins]

<div>Lenny
You and I had the same thought. That is what I did. And it works. Thanx again. Capt B
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[markyvette]

Ditto with the one-way valve. Be advised that it's not fool proof. Hair and stuff can lodge in there and leak back into the bilge. Yes, I did the one way, but my recent survey told me I had to have a siphon break installed on both bilge pumps hoses auto & manual. Fair enough. You hear enough stories about boats taking on water for this reason - so I did it.