Bilge Pump and Check Valves

[Janae]

We need a bilge pump - though we've come to learn most of them specify that the boat doesn't have a check valve. We need a check valve in our boat, otherwise the back flow of water in the line contains enough volume to pour back into the bilge and cause the pump to continuously stay on. Sucking our batteries dry.

Does having a check valve with most bilge pumps not REALLY matter? Does anyone have this situation? Looking for help.

Thanks!

[rtbates]

My experience has been that the majority of centrigal pumps like Rule 500 , etc, won't PUSH a check valve open. My answer, mainly because I dislike Rule500 type pumps with a passion, was to install a Jabsco digraphm pump. The check valve is in the intake or suction side. No problem..

No Virginia, it's NOT cheap, but then neither is my boat!!!!

[Blue Stocking]

Enter " bilge pump non-return" in the search function. Extensive discussion recently

[David M]

Install a loop that goes above the waterline when heeled.

[HopCar]

A common solution to this problem is to install a small pump as low in the bilge as possible and a larger pump mounted a little higher to handle emergencies. If the hose of the small pump still holds too much water you can step down the size of the hose. I had a customer who had this problem. The small pumps usually use 3/4" hose. My customer stepped it down to a 1/2" hose and that solved his problem.

[Uncle Bob]

Originally Posted by HopCar

A common solution to this problem is to install a small pump as low in the bilge as possible and a larger pump mounted a little higher to handle emergencies. If the hose of the small pump still holds too much water you can step down the size of the hose. I had a customer who had this problem. The small pumps usually use 3/4" hose. My customer stepped it down to a 1/2" hose and that solved his problem.

+1 The perfect way to solve the problem. Small pump for maintainance pumping, large pump for emergency! Separate through hulls too.

[David M]

The problem appears to be stopping the siphon.

[Uncle Bob]

Originally Posted by David M

The problem appears to be stopping the siphon.

There should be no siphon, unless the discharge through hull is below waterline. If the problem is the water in the line after pump switch off is of sufficient volume to restart the pump after gravity returns it to the sump then the pump is too large or the sump is too small. Simplest way to solve problem is to install a small pump as suggested earlier. Cheers.

[allanpeda]

Originally Posted by Uncle Bob

There should be no siphon, unless the discharge through hull is below waterline. If the problem is the water in the line after pump switch off is of sufficient volume to restart the pump after gravity returns it to the sump then the pump is too large or the sump is too small. Simplest way to solve problem is to install a small pump as suggested earlier. Cheers.

I read an essay recommending two pumps as well. Too bad I'm not following the advice in this article (yet):
ALL ABOUT BILGE PUMPS - Boats, Yachts Maintenance and Troubleshooting

This guy is recommending secondary diaphragm pump if you must evacuate the last 1-1/2 inches or so.

[Janae]

Originally Posted by HopCar

A common solution to this problem is to install a small pump as low in the bilge as possible and a larger pump mounted a little higher to handle emergencies. If the hose of the small pump still holds too much water you can step down the size of the hose. I had a customer who had this problem. The small pumps usually use 3/4" hose. My customer stepped it down to a 1/2" hose and that solved his problem.

Great suggestion - thanks! I think we're going to go with two bilge pumps, like you suggest (Rule 1100 and Gold Series 2000). We're going non-automatic, as well.

[Janae]

Originally Posted by Blue Stocking

Enter " bilge pump non-return" in the search function. Extensive discussion recently

Thanks for this tip! This post was incredibly helpful! We'll be removing the check valve, and installing two pumps. Now we know!

[zeehag]

my rule 500 gph doesnt suck bckwards- will allow some small amount of water to back flow but isnt much. sailing doesnt bother it-- water doesnt come in from that source.... goooodluck. mebbe the hose is cracked???? that will make it difficult to pump out the bilges without wetboatitis... saw that in gulf on boat i sailed with someone else-- was his boat--- eeps--most wet one....bubba didnt like it much....allthe pumped out water returned to on top of the cabin sole.... eewwwww....

[boasun]

With the two electric pumps add a manual pump to the list. It may be needed if the batteries can't carry the load. And on most boats/ships I've worked on we also had a stripping pump that can be placed where we needed it in order to strip out small or large flooded areas. Usually a Jabsco with an electric motor, and associated hoses.

[zeehag]

mine has 2 electric rules, one is 2200gph, on 500 gph, i have 2 hand pumps, and 6 buckets...i am ready..... also--i sail a formosa, so may be needed..LOL--cannot be too ready for water coming in.....

[Cheechako]

Years ago I installed a large new bilge pump and outlet hose in my boat. The hose was 1.5" diameter. The old pump hose looped way up under the coaming...adding an extra 7+' and more head for the pump to push against. Sometimes I think things through too much toward "improving" them. I couldnt visualize that there would be a problem under sail so I eliminated the loop. Shortly afterward we were out sailing and I though I heard the bilge pump. When I lifted the floor board the water was about 2" below the cabin sole! To make a long story short, I had to add a check valve. I just used a bronze flapper valve, but I made sure it was mounted horizontal so it would open/close easy. The loop would have been better. To this day I dont know how the siphon started and then was stronger than the 5000 GPM bilge pump....