Bilge pump dilemma

[zoidberg]

In my refurb fervour, I've discovered the previous bodger had installed two 'lecky bilge pumps c/w two different diameter outlet pipes. These were 'siamesed' into one 2" through-hull outlet.

I'm satisfied the pumps themselves are sound and serviceable, although I'll replace the 'lecky wiring, fuses and switches. I'll supply them from two separate 12V batteries.

The question I need to resolve is whether again to fit 'two-into-one' or provide a new through-hull fitting so as to give each pump its own unimpeded outlet.

What does the congregation think of the balance of advantage?



The small one in the middle I'll use in a 'roving' mode to empty cockpit lockers.

 

[Neeves]

I dislike drilling extra holes in a hull.

Many though hulls have intermittent use, galley sink, salt water to galley - etc - can you use any of these with one of your bilge pumps.

Jonathan

 

[Dutch01527]

Not an expert on this area but I would consider fitting one way valves and keeping the 2 in to one set up.

 

[jakew009]

I just went through this myself and ended up putting another through hull in.

Everything else felt like a bit of a lash. One way valves can get blocked, not what you want on an emergency system.

Tee’ing in without a one way valve could mean you end up with water coming out of places you don’t expect it to in an emergency.

 

[Stemar]

Tee-ing without non-return valves means that when the first pump starts up, unless the pipe runs are thought through, it'll send a good bit of its water back out of the other one. Allthe same, I'm not a great fan of non-return valves, because they reduce the pump's output significantly. Far better to swan neck the pipe, IMO.

 

[RunAgroundHard]

The single outlet has to be a larger diameter as the two inlets. If not, it has to be much shorter than the two inlets. In addition, run the hoses in a swan neck fashion where the outlet is lower than the two inlets, even if just a little bit lower.

I have a similar set up, electric and engine powered bilge bumps, tied into a Y section then to the outlet. There are no NRVs installed and works perfectly.

Outlet is above waterline.