Bilge pump system redesign – part 1

So the boat when I bought it had just one bilge pump, a lil 500GPM one with a float switch



A few problems with this

– 500GPM is a not very power bilge pump at all, and won’t be much help

– The float switch is waaaaaay up the bilge, so by the time it trips the bilge is already pretty full – also it doesn’t drain it out very far, meaning I still have several inches of water in there at all times. Which is pretty gross.

First I reinstall the manual bilge pump hose with a fresh shiny new one


It’s the corrugated cream coloured one

Next thing was to remove the 500GPM pump and replace it with a 500GPM pump. Whaaaaaa?

The new one was automatic, which means it doesn’t need a float switch and just switches on every 3 minutes for a second. If it feels resistance (from water) then it keeps pumping until it’s free again. This means that it will start pumping a lot earlier than the old one, and keep going until all the water is almost gone. I also downsized the outlet hose to 1/2″ from 3/4″, so there would be less ‘backflow’ when the pump stops.

The next thing would be where to output it to. I decided to use the existing bilge pump outlet for the new, bigger pump I was putting in, so I had to put in a new outlet. After reading on the internet, a lot of people suggested putting it in the cockpit, so I wouldn’t have to drill a new hole in the side of the boat, and also if I was sailing I could tell the bilge pump was running by the fact my feet would be wet!

Here is the hole and the fitting




To drill the hole I used this bad boy



Once the outlet hose was installed, I had to wire the pump.

The original pump was wired direct to the batteries which were next to the bilge, but since I had moved the batteries I needed to do something else. I decided to wire this one direct to the panel, since it wasn’t a critical bilge pump (the bigger one is my ‘oh shit’ one) and this way I could switch it off if the auto function was keeping me or someone else up at night.

I ran some 16AWG boat cable through the bilge and hooked it up to the panel.




Part 2 will deal with the main, larger bilge pump


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