Bilge pump to pump out below waterline

[Clivevon]

To answer your question - if you run a bilge pump to a below the waterline through hull you dont need a check valve - you need a swan neck - a loop of hose which runs right up to just under your side deck - with it double clipped with A4 quality jubilee clips. Even if your through hull is above the waterline you still need a swan neck - think heeled. BTW stop thinking about what is convenient - focus on what (might) stop your boat from sinking out from under you when she is trying to do just that....
Check valves - we call them non return valves - significantly reduce the capability of your bilge pumps. NO. NO. NO.

[captlloyd]

Originally Posted by MJH

During my boat search I viewed one 40' sailboat that resembled the bilge areas you mentioned but certainly not that many. It was caused by the basically flat floor surface with very shallow bilge areas with pumps located here and there...I couldn't believe there were so many...I didn't buy the boat despite the attractive price.

To me this speaks against those using a boat for something other that for which it was designed, particularly in the extreme as is this case. The many advantages of one use go against the advantages of the other and possibly to the determent of the boat's safety itself.

I have no solution to your issue other than starting over again with a cruising boat to go cruising in.

~ ~ _/) ~ ~ MJH

I totally agree that you have no solution, apparently they already own the boat. A few limber holes would solve the problem.

[Lepke]

Commercial fishing boats end up with structural members breaking up the bilge like this sailboat. Limber holes are cut before the plating goes on. Otherwise after the steel is coated, either cement or foam is poured into the separate areas and the top of that becomes the new bilge.

[captnknopf]

There is a (rather expensive) bilge pump made to completely dry the bilge but I have seen plans to make one inexpensively. It is basicly a sponge in a plastic box with a vacuum tube coming out of the top of the box. All lines are hooked to a small vacuum pump and timer. It can be set to every hour or once a day or what ever. It is only to remove condensation or small drips. A regular bilge pump with float switch should be used but not in every cavity as if there is a big leak, it will flow from one cavity to another. Put in the lowest place in every cavity it will keep the bilges bone dry.

[skatun]

Just to clarify, I do have two automatic bilge pumps(floating switch), where one is used as a shower pump(it gets flooded when water in bilge reach 10cm) and one in engine bay. In addition I have a 230V bilgepump, two manual ones on deck and I am considering getting a ryobi battery operated one as well.

I just emptied the aft of the boat, so I will most likely put it off to next winter with installing the outlet all the way at the back above the waterline. The main task now is to get the diesel heater up running(serial with the HVAC) and the new electronic valves on the septic tank.