There's very little as disgusting as stepping into water in the bottom of your boat, which is why a good bilge pump is so important. Water always ends up in the bilges, whether it comes in through packing glands around the propeller shaft, down from the deck, or through the seams of a wooden hull. The water's always going to be there, so you need something to get it out.Bilge Pump Basics
The basic bilge pump is a 12 V DC submersible electric pump. It does not need to be fast, but it does need to pump water vertically to get it out of the boat and over the side. One thing you should include is an automatic float switch, so that the pump turns on once the water reaches a certain level. You don't want to be surprised by the amount of water in your boat.Installing Your Bilge Pumps
When it comes to expelling water from your boat, you need more than just one bilge pump; you need a whole system. In addition to your pump or pumps, you also have to arrange for bilge blowers, plumbing, and ventilation. You also want at least two pumps, more if you have a larger boat.What it Won't Do
The one thing a bilge pump won't do is stop your boat from sinking if you have a leak. Their design is for small amounts of standing water, not dumping large amounts of water over the side rapidly. For that, you want an emergency pump, and you need to make sure it has enough capacity for your boat. Always get the right pump for the job.Washdown Pumps
Even when you place the pump in the bilges, you want to run your deck wash pump, plumbing, and ventilation separately from your bilge pump. A good deck wash pump needs to move more water, and it also wants a raw water connection. It's meant for cleaning off your boat, not getting the water out of it.