There are manual models, but most bilge pumps are electric. They are automatic, detect the presence of water and are activated by a float switch. The pump itself consists of an electric motor, enclosed in a waterproof case. This pump must be placed at the lowest point of the boat.
Monobloc pumps
Modern electric pumps are one-piece, with the motor directly driving a small turbine that pumps water through a strainer and out through a pipe connected to a through-hull. The strainer, a kind of screen, traps debris and prevents it from blocking the rotation.
The high speed
A pump is characterized by its flow rate, i.e. the number of liters it can evacuate in one hour. Numbers may seem important, but they are never important enough when it comes to fighting a leak. Economy is a bad advice when it comes to bilge pumps: if a small model, from 1200 l/h is enough to evacuate run-off, having a flow rate of 4000 l/h is a minimum on board a unit of any importance.
A control panel
The pump should start automatically when needed, but it should also be possible to force it to start, even if only to check that it is working. It must also be possible to switch it off for handling or transport. Therefore, you need a switch with three positions: On, Off and Automatic, as well as a light that will indicate when the pump is on.
Reliable connections
The power supply should preferably come from the starter battery, as this is the one most likely to be properly charged in all circumstances. The dedicated switches incorporate the three-position toggle, the indicator light and a fuse. Connection is relatively simple and a diagram is provided with the switch. The connections will of course be made using tinned, perfectly crimped and insulated connections.
A removable support
When access is difficult, a dismountable support can be made that will greatly facilitate assembly and future maintenance. A simple aluminum plate with the bottom end bent at right angles will receive the pump and its float. The whole unit can be removed for cleaning without having to bend over or wade through the dirty water.
A simple assembly
The assembly of new equipment is greatly simplified by the detachable strainers and bases that form the support of the device. Simply screw each of them onto the support, clip the pump and float onto it and connect the discharge pipe, which must open out through a grommet in the plating. The height of the support is then adjusted before proceeding with the electrical connection.
The bilge pump is only a palliative and its efficiency should never lead to neglecting a water inlet. Hearing it work should alert you rather than reassure you!
