Bilge pump dilemma
I want to install an automatic bilge pump in my Pearson 30 and I am weighing different options…
Do I install an electric diaphragm pump "high and dry", with a pickup hose/strainer going to the bilge and separate float switch, or should I go for a smaller, self contained centrifugal unit (like the ones made by Rule).
I have a diaphragm pump ready to go, but it is bulky and hard to find a good place to install it. The cockpit locker seems a logical place, but it wouldn''t be very protected from fenders, lines, and boathooks. It also draws quite a bit of power (7A) and doesn''t have a very high capacity (4.5 gal/min = 270 gal/hr). Do diaphragm pumps perform closer to their rated capacity than centrifugal pumps?
The smaller units seem to have a higher capacity and draw less power, which seems an advantage to me (I understand that smaller boats need bigger bilge pumps). Are centrifugal pumps more prone to back siphoning or other failure? Anyone have any experience with these pumps?
Also, is there a rule of thumb on the longest hose run that a typical pump can handle? I''d like to discharge through the stern, but with a hose run of 15 ft or so, I am not sure that''s feasible. Would it be better to exit through the side (with a vented loop). By the way, would I still need a vented loop with the diaphragm pump or does its design act as a siphon break?
Thanks for your insights!