Check valve

JerryA

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Oct 17, 2004
549
Tanzer 29 Jeanneau Design Sandusky Bay, Lake Erie
My boat has a small bilge pump in the sump for the shower. The initial problem was that the hose was so long to the thru-hull that once the pump shut off a good deal of water ran back into the sump. I installed a check valve about a foot from the pump. So then I created a second problem. 50% of the time air would be trapped between the pump and the check valve, and the valve would not open, and of course the sump wouldn't drain. I solved the air problem by drilling a 1/8" hole in the side of the hose just ahead of the valve. When the pump turns on, the air has a place to escape and then a bit of spray will come out of the hole into the sump. I noticed that a side benefit of the spray is that it stirs up any residue in the bottom of the sump which then gets pumped out. Seems to be working for me. Maybe a solution for others.

JerryA
 

SG

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Feb 11, 2017
1,670
J/Boat J/160 Annapolis
Where is sump for the shower? Why can't you conduct the drain to, say the sink drain for the lavatory?

Where does it go that is so far away?

 

JerryA

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Oct 17, 2004
549
Tanzer 29 Jeanneau Design Sandusky Bay, Lake Erie
Where is sump for the shower? Why can't you conduct the drain to, say the sink drain for the lavatory?

Where does it go that is so far away?

The sink drain is almost as far away. And there isn't a good way to get the hose to it without the hose becoming an alternate path for the sink drain. The pump isn't even in the shower/head area. It's placed closer to the centerline to get depth I assume. Also, my galley is on the starboard side, opposite of this early drawing.
 
Dec 2, 1997
8,708
- - LIttle Rock
Is the galley sink the only sink....there's no sink in the head that has a drain line you could tee into?

Plan B maybe:
Have you considered just routing the the shower drain directly overboard through a pump with a switch you can turn on when you need it instead to into a sump? You'd prob'ly need to install a new above-waterline thru-hull too. I suspect you could run it under the vanity (assuming there is one in the head that has a sink in it), which would keep it short.

Just an idea....
 

RoyS

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Jun 3, 2012
1,739
Hunter 33 Steamboat Wharf, Hull, MA
Centrifugal type pumps, typical for bilge pumps, usually cannot produce enough pressure to open a check valve. Even shower sump units with an integral check valve sold in marine stores usually do not work.
 
Jul 12, 2011
1,165
Leopard 40 Jupiter, Florida
Interesting discussion because I have the same problem and was considering the same solution (without the hole in the hose). I've got a small centrifugal bilge pump acting as a shower sump that Y's into the sink drain. It always leaves an inch of water in the sump, which begins to mold after a few days. I was considering adding a check valve right after the pump to at least eliminate the backwash, but RoyS comment implies that this won't work. Is there a better way to get it dryer?

Similarly, since installing a dripless stuffing box I still have occasional nuisance water in the bilge (still searching for minor leaks, AC condensation, etc.). Any suggestions for a small-volume primary bilge pump to eliminate the last inch of water?
 
May 24, 2004
7,129
CC 30 South Florida
Any suggestions for a small-volume primary bilge pump to eliminate the last inch of water?
The cure for that is elusive at best. In older boats there will be many gallons of water trapped in the hull stringers below the sole which at some point will make their way into the bilge. I find the worst problems are deposits of anything from oil to particles of wood and some smells that will enter the cabin. There are easier ways of dealing with the deposits and smells than trying to keep the bilge dry.
 
Dec 2, 1997
8,708
- - LIttle Rock
here are easier ways of dealing with the deposits and smells than trying to keep the bilge dry.
Cleaning the bilge--actually CLEANING it instead of just pouring bilge cleaner and/or bleach into it and calling it done--a couple of time a year is the easiest.

However, keeping a sump clean is the only maintenance job on a boat that requires -0- manual labor. All you need to do to
eep your shower and sink drains and sumps--and strainers too--clean and sweet smelling is put a few ounces of Raritan "C.P. Cleans Potties" into 'em once a week when it can stand at least overnight. Raritan only markets C.P. as a toilet bowl cleaner, but it's also the best sump and drain cleaner on the planet because it's a bio-enzymatic cleaner that not only destroys odor on contact, but the enzymes in it "eat" hair, soap scum, grease, body oils etc that clog pumps and screens.

Sumps: Make sure the sump is about 1/4-1/3 full of water...put 2-3 oz of C.P down the shower drain. That's it. When you come back, run plenty of clean water through the sump to rinse it out.

Sink drains: close the seacocks...put an ounce or two of C.P. down the drain...fill the drain with water. That's it. When you come back, open the seacock and flush out the drain with clean water.

C.P. can sit in drains and sumps indefinitely without any problem--although it ceases to accomplish anything after about 24 hours...so no rush to get back and flush it out. Use it once a week, or just before the boat will sit each time and your drains and sumps will stay clean and odor free and your strainer screens clog free.

And btw...C.P. is also an outstanding toilet bowl cleaner!
 
Apr 8, 2010
1,942
Ericson Yachts Olson 34 28400 Portland OR
One assumption perceived here is that a centrifugal (i.e. "Rule") pump is adequate for bilge pumping.
I say 'no'. :(

Only thing that pump technology has in its favor is being cheaper at the store. Their tendency to air lock is scary, and we have had this happen multiple times with a centrifugal pump.
I would suggest using a different type of pump design with built-in "check valve" action.
All of the factory pumps on our boat were and are Jabsco diaphragm type pumps. Like the model 37202-0000.

Note that the GPM number for the Jabsco diaphragm pump is an achievable flow number, whereas the stated flow rate for the Rule is not close to being 'real world' - they and their centrifugal pump competitors were roundly criticized for this in extensive testing done many years ago by Practical Sailor.

Hope you get that shower bilge drier... I have done deliveries in boats with loose water sloshing out of the shower sump in the head compartment, and having to put on shoes to keep my feet out of some gross bilge water in order to use the head @ 3 am was no fun at all! (With the boat rolling, of course...)
:)
 

JerryA

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Oct 17, 2004
549
Tanzer 29 Jeanneau Design Sandusky Bay, Lake Erie
Peggy,
I don't have a shower drain exactly. The floor is slatted teak. The space under the slats is sealed and acts like big funnel over to the opening that directs the water into the sump. There is a sink in the head, but because of where the sump is located and the way the area is sealed, I can't get to that sink drain without adding more length to my hose. The check valve is the rubber type similar to a joker valve, only 3/4". I don't think I would trust it if it were the bilge pump, but for the shower I'll not get too concerned. Maybe I can fit a diaphragm pump when this one gives up.

JerryA