Bilge pump question

[Steelshooter]

We recently bought a new to us Beneteau 440 and had a leak in the pressurized water system which went undiscovered while out sailing. I discovered the water pump running when I went below and naturally the water drained into the bilge. What concerned me was it took quite a long time for the bilge pump to drain the bilge and the water flow at the through hull was barely a trickle. I cleaned the strainer which had quite a bit of debris in it but the output remained the same. It's a diaphragm type pump which I have no experience with and when looking for a replacement I was surprised to see it rated at less than 300 gph. I would feel more confident with a higher output bilge pump and honestly don't know why something like a Rule 2500 wouldn't work. Do any of you have any advice?

[rslifkin]

A small diaphragm pump or small centrifugal as the primary bilge pump is common, as they can draw the water level down lower than a large pump will. Diaphragm pumps also don't have hose drainback issues.

That said, for setups with a small main pump like that, there should also be a much larger pump set to trigger at a higher water level to handle any large amount of water.

[sailormed]

On my boat I have a reasonable standard bilge pump, but the manufacturer proposes a “high water bilge pump” with a much higher capacity as an option when buying the boat. The 2 bilge pumps solution is very common and has a lot of advantages.

[SVHarmonie]

Bilge pumps are a complex issue, with lots of competing priorities.

I am not sure what a “trickle” is, but I suspect that your existing bilge pump is in need of an overhaul. It is an expensive pump, and is well worth fixing. One of the advantages of a diaphragm pump is that it IS rebuildable, and it should be mounted in an accessible place.

A good solution is to use your diaphragm pump to remove routine rain drips and condensation water, and have a second bilge pump set higher up to handle any “issues.” It is a good idea to have an alarm go off whenever this pump comes on so you know there is a problem you need to address.

It is helpful to realize that even a large bilge pump is not going to keep up with the inflow if you have an actual hole in the boat bigger than you can plug with your finger. If you can’t contain a significant leak, or stop it, a bilge pump isn’t going to do more than delay things..

[DDabs]

As far as bilge pumps go, I've had really great success with Whale Gulpers. They do well against clogs as they seem to pump through just about anything, and with the right connections they can be mounted just about any which way as well.