Diaphram Bilge Pump - Best choice?

[foamcore]

They are a choice for a bilge pump. If you will have only one pump, they are a good choice. I like um because you can use the inlet hose to remove water from spots that don't drain, sort of like a vacum cleaner. That was handy on my old boat.With care they last a long time and are rebuildable. Other designs are better for moving large volumes of water though.

[batkins61]

One problem with a lot of sailboats (e.g. my Beneteau 361) is that there is very little vertical space between the floor boards and the bilge, and the sump is about 2"x3"x2" with the two existing intakes (manual and electric) already stuffed in there. There's no room to put a pump under floor boards, so it has to be mounted elsewhere with an intake hose. What options are there for this situation, other than a larger or second diaphragm pump?

[cal40john]

Originally Posted by batkins61

One problem with a lot of sailboats (e.g. my Beneteau 361) is that there is very little vertical space between the floor boards and the bilge, and the sump is about 2"x3"x2" with the two existing intakes (manual and electric) already stuffed in there. There's no room to put a pump under floor boards, so it has to be mounted elsewhere with an intake hose. What options are there for this situation, other than a larger or second diaphragm pump?

You have relatively small pumps to take care of little leaks and dry out the boat. The big pump doesn't have to be in the lowest spot.

John

[batkins61]

Originally Posted by cal40john

You have relatively small pumps to take care of little leaks and dry out the boat. The big pump doesn't have to be in the lowest spot.

John

Ok, that makes sense. There's room behind the engine between the transmission and the stuffing box, off to the side. Is there a safe way to T into the exhaust to save a cutting another hole?

[cal40john]

Originally Posted by batkins61

Ok, that makes sense. There's room behind the engine between the transmission and the stuffing box, off to the side. Is there a safe way to T into the exhaust to save a cutting another hole?

No. The people that write exhaust installation guides have gone to a lot of trouble trying to keep water from backing up the exhaust system and ruining the engine. Plumbing a 30 gpm or more pump into the exhaust seems to me to guarantee a hydro-locked engine.

The offshore racing crowd doesn't even allow tee-ing into sink or cockpit drains. I did use one of the additional cockpit drains added to my boat to tee into. Previous owners offshore raced my boat and had to add cockpit drains to meet the rule. So I still have 3 drains to empty the cockpit even if the 4th one is slow due to the bilge pump using most of its capacity. Though I might be sorry someday when the boat has a major leak down below in the middle of a big enough storm to keep the cockpit awash with waves.


John