Bilge pumps

[zoidberg]

I'm shortly to fit new bilge pumps into a 27' deep-keel sailboat with a 4' deep sump below the engine.

What d'you reckon is the optimum 'fit' of bilge pumps?

 

[Porthandbuoy]

The largest that will fit. What's the useable width? Have you room for hoses & elbows?
Your 4'? Is that to the discharge skin fitting? Don't forget the capacity of most pumps are given with zero head. The capacity will be seriously reduced if it has to lift the water 4' or more.

 

[PhillM]

Depends on what you want it to do. Emptying a little rain water out is one thing but dealing with the ingress from, say, a failed skin fitting or collision is another. In the first instance any old electric pump would do. In the second you not only need a pump with the capacity to move enough water, but also a battery bank capable of sustaining what it would need to draw. Perhaps, consider a engine driven one because you are going to need to start your engine to power an electric one for any length of time of time anyway.