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post #1 of 3 Old 02-03-2009 Thread Starter
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Bilge Pump Discharge Location, Other Qs

Hi all, I know this is pretty well-traveled territory, but I still have a question for you all. I was in WM today and they had a schematic for different bilge pump installations, including one for a sailboat like mine (Cat 30). This schematic was produced by Rule, who should to know a thing or two about bilge pumps. Anyway, in an installation for my boat, it showed a short route for the discharge hose, exiting near the rubrail midship. My question is this: If I went this way, and included a vented loop, would I still get back flow when heeled over on that side? It seems like this would cut a lot of friction loss and head out if I didn't run the hose all the way to the stern.

While we are at it, I have one more question if you don't mind. My manual bilge pump is plumbed in such a way that it includes a 3-way valve which allows manual pumping of the waste tank overboard. Is this normal? I would like to eliminate the 3-way and just plumb the manual pump to serve for bilge only.


Thanks in advance, Bill

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post #2 of 3 Old 02-03-2009
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If the vented loop is above waterline at any angle of heel there should be no backflow, water don't run uphill and the vent prevents a siphon.
I don't want to think about how stinky the boat would be if someone used the manual bilge pump to empty a blackwater tank.
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post #3 of 3 Old 02-04-2009
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If you have a manual bilge pump hooked up to your holding tank, it should discharge underwater—not above the water line for sanitation reasons.

If you're going to disconnect the diverter valve, you can lead the bilge pump to an above the waterline through-hull, but if you're still going to want to pump out the holding tank, that should probably go to the underwater through hull used for the head discharge.


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