Hi Nick,

The previous replies are all very valid. However, I think we all agree that a well built boat should not need a bilge pump at all.

For a "" looks" pump you may easily combine it with water cooling for the motor and\ or the E SC- although again a good choice of components should make such cooling unnecessary in slow or scale boats.

Amyway, for cooling and\or looks alone simply pipe from a small scoop directly behind the propeller - to the outlet ( well above the waterline).
Good luck.

Dr John F. Leeds and Bradford. MBC. 😊😊😊

Nick,
Water discharges for boats DO look great and I would encourage doing so if you think it is appropriate. That said, if you want a bilge pump system, it should be separate from any "for looks" system. The "looks" system needs a dedicate water supply and will not be able to draw from the bilge if needed. Also, how would you know if your overboard stream is from the "looks" system, or that you are sinking?
Pumps are very inexpensive so both systems should not hurt your bank account too badly.😀

Thanks all notgot to that bit in boat build, just thought it would look cool in my Huntsman, then again I'd have the facility there to pump out,should under full power turning allow a modicum of water into the vessel.

Nick,
Many good suggestions have been posted for pumps. As for activating them, you have options as well. For a bilge pump, automatic activation is best because if your boat does leak, you often will not notice it until it begins to act funny, by which time it will have taken on a lot of water and your pump may not be able to save it.
Using a water sensor connected to a relay to activate the pump is a simple way. You could also add a R/C electronic or mechanical switch to manually turn on your pump.
As pointed out, it is best to build in such a way as to not need a pump, but then again I have a generator for my house... because I can not control the weather.😁

If your model is leaking that much It would be better to make it waterproof. You can buy self bailing attachments that require no power and add no weight. As others have said, for fire pumps etc, car windscreen washer motors work well.

Used a garden spray pump, 6V and self priming, controlled by RC switch. Works well
Used it on a twin waterjet model that was difficult to seal.
Even then, not that much water ingress so unsure worth the trouble.

Nick I have used 6v self priming suction water pumps for my fire boats, and also in one tug as a bilge drainage pump.
I've only used via an rc switch not automatic.
Her is the link to such a pump, hope that helps you cheers Colin.

https://www.ebay.co.uk/itm/254555464932?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=aOWTo0jgSRC&sssrc=2349624&ssuid=LGaRsqMfQ6y&var=&widget_ver=artemis&media=COPYk

NickD, depends on how much water you are likely to get in the boat - for small amounts why build a complex pump, and just use a large plastic syringe with a flexi pipe on the end to get to awkward corners when you bring the boat ashore. If you want a full electric pump, you will need to either have all bilge water drain to one internal point, or have multiple suction pipes in all areas water can collect. The simplest water pump is a car windscreen washer pump, and are cheap in the UK. BUT they do need 12v power. They are powerful, and I use one in my fire tug to shoot water from the fire-jets. They shoot about 6 feet.