Sump Pump for Very Shallow Bilge

[thinwater]

The space between the bilge and the floor of my F-24 is only 3/4-inch. Conventional pump/switch systems are set up for 0.75-2" activation. So what are the choices, and does anyone have experience?


*Arid Bilge. I will look into this. But it is really larger, more expensive, and probably requires more power than I have in mind. I have only a group 24 battery and 50W solar. I could plug in.


* Smaller components. The leak rate is never more than a few gallons per day. I'm sure I can build what I need, based on smaller, non-boat store stuff. But a proven system would be nice.


In fact, I generally clear my bilge spaces (triamaran with 7 compartments) with an oil vacuum (not used for oil, obviously). Most never get more than a liter per month.

[wingless]

Why not setup a wick system, using the wick to saturate / elevate the moisture and a large wick to distribute the moisture to evaporation?

[thinwater]

Originally Posted by wingless

Why not setup a wick system, using the wick to saturate / elevate the moisture and a large wick to distribute the moisture to evaporation?

There are times when 5 gallons per day removal are needed. Sometimes more. Depends on seas.

[HopCar]

If I had this problem, I’d ask thinwater, oh wait. Never mind.

The Rule LP900 comes closer than most pumps to working in this situation.
It will turn on with only 1.3 inches of water. Won’t fit under the floorboards.

[MartinR]

Small diaphragm pump, on a timer?

[CarlF]

A manual Whale supersub might fit (I think you can rotate the hose connection).

https://www.defender.com/product3.js...4229&id=938565

I used to have one and it pumps down to very little water. Then use the sensor part of a home leak detector to turn it on (this one senses 1/32" so might be too sensitive but you could always put a few shims under it until you get the right height).

https://www.amazon.com/Glentronics-I...122487&sr=8-45

Instead of the pump you could put a Whale Gulper 320 in a nearby compartment and run a hose to a low strainer like this:

https://www.defender.com/product3.js...4256&id=121052

[thinwater]

Originally Posted by MartinR

Small diaphragm pump, on a timer?

Yup, I've been thinking about timer instead of float. A few minutes twice a day would do it. Manual switch if more is needed. Good idea!



What I don't like about diaphragm pumps is that they freeze in the winter, and often burst.

[noelex 77]

Originally Posted by thinwater

What I don't like about diaphragm pumps is that they freeze in the winter, and often burst.

You could use a remotely mounted impellor pump such as one of the Jabsco Puppy models. This type of pump does not like to be run dry for long periods so it would be better to be switched manually or via a float switch, rather than a timer.

[wingless]

Originally Posted by thinwater

Most never get more than a liter per month.

Originally Posted by thinwater

There are times when 5 gallons per day removal are needed. Sometimes more. Depends on seas.

Two totally different extremes.

A wick would work for the liter per month.

Assuming the boat normally has severe attitude changes during operation, then trap scoop bucket w/ internal sump pump could use those normal motions to move / confine the water into a smaller area for pumping.

[CarlF]

I have one of these 12v timers for lights. Works great. Don't see why it wouldn't work for a pump.

https://www.amazon.com/JVR-Programma...NsaWNrPXRydWU=

[bobnlesley]

You don't need to squeeze the pump into that small/shallow bilge, just the switch.
One of these waterwitch units should fit https://www.google.com/search?q=wate...-KyFmpj7XKH5M: we've used one for three years and been very happy with its operation

[thinwater]

Originally Posted by CarlF

I have one of these 12v timers for lights. Works great. Don't see why it wouldn't work for a pump.

https://www.amazon.com/JVR-Programma...NsaWNrPXRydWU=

I was looking at that one. Thanks!

[wefleenor]

Install an electric switch and a peristaltic pump. Then you only need to install the switch and the uptake tube for the peristaltic pump. Added advantage is the pump will not release water back to the bilge when pumping stops.

[MartinR]

Originally Posted by bobnlesley

You don't need to squeeze the pump into that small/shallow bilge, just the switch.
One of these waterwitch units should fit https://www.google.com/search?q=wate...-KyFmpj7XKH5M: we've used one for three years and been very happy with its operation

The same units I am using in various applications

[senormechanico]

If you are worried about a diaphragm pump freezing, why not just add an antifreeze drip system to the bilge? Oh wait...