The sensor switches on only when the probe is covered in water, then it switches off again after the level has dropped to the bottom of the probe. All you have to do is mount the unit in the bilge and set it to the correct height. However, note that if you have a very large capacity pump you may need to also hook up a relay to take the higher current draw. I found the instructions provided with the Bilge Level Monitor very simple, yet detailed enough to allow the average boat owner to fit it himself. By combining the SM Bilge Level Monitor with a three-way switch as an override, I believe you'd have the best of both worlds and a very reliable automatic bilge pump.
Many people use a small bilge pump mounted on the transom to pump water to the live bait tank.
There are many different ways to set up a live bait pump and this will be covered in later issues. However, why not at the same time use the same pump as a deck wash outlet. All you need is a three-way garden valve which is available from any hardware shop. Fit this in-line with the bait tank pump, and then have a detachable hose which you can snap onto one of the arms of the valve. Turn the valve on the three-way fitting and you have a handy hose which can be used to wash down the boat.