Bilge pump choices

adamk · #1 (**permalink**) 01-03-2003

I''m getting ready to add a second electric bilgepump to my Kelly Peterson 46. The boat currently has a deep sump w/ a 1500 gph Rule pump in it, leading to a dedicated thru hull w/ seacock. Switch is about 6" above the pump. I''d like to add a small automatic pump next to the big one, to handle day to day drips. What is the best way to handle the outflow? OK to simply put a tee in the existing pump line?

Another bilge pump question? Is there an advantage to the belt driven diaphragm pumps as opposed to the more common centrifugal submerged pumps? They''re much more expensive, but I can''t see a benefit. Thanks for any help.

Sailmc · #2 (**permalink**) 01-03-2003

A diaphram pump will suck your bilge truely dry. It will not loose prime when the water level drops. I have one and love it. The only draw back is the capacity. For your application with a large sbmersible, a diaphram to get that last gallon makes sense.

lecomte38 · #3 (**permalink**) 01-03-2003

The diaphram pumps are good if you have excess pump height. From the bottom of my blige to the top of the loop is 8''. The submersible pumps are not rated to pump to that height.

pirateofcapeann · #4 (**permalink**) 01-03-2003

You don''t want to “T” into the existing pump line of a centrifugal pump. You would be then pumping water right back into the bilge through the unused pump.

A friend of mine has a small 360 GPH pump mounted in the very deepest part if his bilge, on a line reduced to about 3/8-inch copper tubing. This pump is powered through the same float switch as the larger pump. Here''s his secret, he''s run the tubing to discharging just a couple of inches above and into a cockpit drain. Now, as he''s sailing along, he has a visual and audible "high bilge water alarm" of sorts. Running the main pump dry for the short amount of time it takes for the smaller pump to clear the bilge is not a problem for a centrifugal pump.

I think his idea is a great one, but I can’t use it on my boat. I keep that last space between the floor timbers filled with seawater as I have a swell-fit bung there. Now, my boat don’t leak like some wooden boats do and I’m afraid that if that bung ever dried out and shrunk, I could be in a world of trouble!

Pi

Stormer · #5 (**permalink**) 01-07-2003

I also have a rule 1500 gph pump with separate float switch and dedicated through hull. This is located in the main bilge but not the deepest part.

I have installed a "smart" Rule 500 gph pump in the deepest part of the bilge. It has a built in float switch and will turn on when the water level rises slightly. Where the hose is attached, I put about 1" of 3/4" tubing to bridge the output lip on the pump and a 3/4" to 1/2" L-shaped connector. After making this connection, you have a 1/2" fixture to which you can vertically connect 1/2" tubing. I then run the 1/2" tubing to a separate (existing) sump drain fixture elsewhere. I dont actually mount the pump, but lower it down as far as possible into the deep bilge using the vertical 1/2" tubing. It has worked very well.

You don''t want to T into the existing bilge line. If you are underway and the pumps are running - you will only be pumping out water at the same rate as the single pump at the electrical expense of two pumps. You also don''t want to add another through hull if you don''t have to. Is it possible to lead the new pump output somewhere else?

Good luck.

Matt