Small diaphram pump to deal with bilge pump backflow?

[paradox]

I have never had a dry bilge in my OC48
I elevated the bilge pump switch by 1/2inch on a piece of starboard
this way, the float switch comes on when there is enough water but does not cycle on and off regularly
I have a second, larger bilge pump about 6 inches higher than the regular pump with its own float switch
Both bilge pumps are wired directly to the battery since the traditional Beneteau wiring goes to the switch panel and the bilge pumps shut off when the boat is shut off
I made a DIY ARID BILGE but I finally bought one and I love it. Pricey, but much better than my DIY system. The DIY system worked well, but I never found a way to get the water overboard.
IMHO
Paradox IV
OC 48 2016

[hlev00]

The real question you should be asking is how do you keep your bilge sump dry. Our 423 is dry nearly all the time. If we get some water we just sponge the last bit dry but we go for months sometimes with now water. We don’t have AC and condensate to deal with. If you do have AC you might check out this 423 group and their solutions. https://beneteau423.groups.io/g/main/message/39395

[oceanblue9]

Originally Posted by s/v Jedi

Use one of those mini shop vacs. You can make a semi permanent install.

DITTO!

[Bluechart]

We had this issue, on our B49, cycling bilge pump, so I kept a small rubber bucket and sponge next to the sump, drying the sump would help for days or weeks. But then I got busy and found the source of the leaks, (stern dinghy/solar arch bolts not properly bedded on deck, and rain followed solar wires into the arch and down into the boat.) now the sump is completely dry.

[sinnerman]

this is an interesting article on how a guy set up an ingenious way to get the last bits of water out of the bilge.
https://panbo.com/a-dry-bilge-for-50/

The problem with almost all off-the-shelf bilge pumps is they:

/a/: are limited to about 1/2" (or more) of water depth before they start sucking air

/b/: have crappy check valves (joker/ duckbill rubber valve in outlet), so when the pump stops, all of the standing water in the drain hose rolls back into the bilge.

cheers.

[Night_Sailor]

I use check valve on both my bilge pumps, and they work well to stop cycling.



If you want a dry bilge, the best thing is a wet/dry shop vacuum with the filter removed. I've thought about using that to raise it to the vacuum and treating this as a sump above the waterline, attaching a drain at the bottom that discharges through a cockpit or galley drain. You would need an inverter to run the vacuum.

[CarinaPDX]

Another vote for the Whale IC pump: it is a complete, smart package with a 320 diaphragm pump and a foot valve with sensor. I have one, and then a large 1-1/2" hose Rule centrifugal pump with sensor mounted a bit higher for when I really need to move quantity. When working out a bilge pump system the sensors are the biggest potential problem so don't skimp there.

Greg

[johnny666]

I had the same problem. Fixed it by installing a a different one way valve from Trudesign rather than the duck bill one originally installed.
Worked perfectly. Install it as close to the pump as possible so that any backflow from below the valve is minimal.

[johnny666]

I had the same problem. Fixed it by installing a a different one way valve from Trudesign rather than the duck bill one originally installed.
Worked perfectly. Install it as close to the pump as possible so that any backflow from below the valve is minimal.
I ordered 2 valves incase the first one didn't last long. It's been there 5 years and going strong.

[risailor]

I had the same problem on my CAL39 and found the use of a check valve just created a 10' head of water in the discharge line that would occasionally stall the pump, causing it to run continuously until the battery ran out.

The solution I came up with was to add a time delay circuit to the bilge pump to keep it running for an additional 15 seconds to better empty the discharge line, enabling the pump to more easily start up the next time the float level caused the pump to engage.

I have attached a picture of the circuit. It has been in operation for going on five seasons with no issues.

I was able to source all of the parts on Amazon.

Good luck.

[noelex 77]

Approaching the problem from another angle: a good solution is stop all the water entering the boat. In this way it can be mopped out once and thereafter will stay dry.

There are many advantages such as eliminating condensation, odour, and importantly allowing the early spotting of problems (little leaks) before they become serious.

A dry boat is not easy to achieve on some models, but if this feasible it will solve your issue and have many other benefits.

[sailingharry]

Originally Posted by risailor

The solution I came up with was to add a time delay circuit to the bilge pump to keep it running for an additional 15 seconds to better empty the discharge line, enabling the pump to more easily start up the next time the float level caused the pump to engage.

This is one of the major benefits of electronic switches such as Water Witch and Atwood S3. I've used and love the $33 Atwood.

[s/v Jedi]

With two keel stepped masts it is very difficult to keep it dry, but I have a new plan: at the point where water will run down into the keel sump, I will fabricate small fiberglass catching funnels with a hose to the grey water disposal.

I have good hopes it will work

Edit: you can even do it without a hose… just let it evaporate. As long as it doesn’t get overwhelmed, it should work.