To say it the easiest way, the bilge is something you want to make sure is functional and installed properly.

A bilge pump is a water pump used on ships and boats to remove bilge water, which accumulates in the bilge, the lowest compartment at the bottom of a ship’s hull. The primary purpose of a bilge pump is to prevent the boat from sinking due to water ingress, whether from leaks, rough seas, rain, or other sources.

• Preparation:
  • Ensure that the boat is secure and safe to work on.
  • Examine the current bilge setup. If there’s an old bilge pump and float switch, note their positions.
• Cleaning:
  • Remove any debris, crud, or old equipment from the bilge area.
  • If there are any screws from the old setup, carefully remove them.
  • Scrub the inside of the bilge to ensure a clean surface. This will help when sealing holes and attaching new equipment.
• Drilling and Fitting:
  • Check the fitting for the new bilge pump. Ensure it fits the designated space in the bilge.
  • If the fitting doesn’t fit, you might need to drill or adjust the space. Use a step bit for precision.
  • Once the hole is drilled, bed the fitting in with marine silicone for a watertight seal.
• Painting (Optional):
  • To brighten up the bilge area and make it easier to see, consider painting it with white bilge paint. Ensure the area is clean and dry before painting.
• Wiring the Bilge Pump:
  • Battery Connection: Start with a ground wire leaving the battery. Connect this to the negative side of the bilge pump.
  • Circuit Breaker: Connect the common center of the activation switch to the circuit breaker. This ensures that the rest of the wiring in the system is protected in case of any issues.
  • Activation Switch: Use a single pole double throw on-off momentary switch. The “on” position of this switch should be connected to the float switch. The float switch then connects to the positive side of the bilge pump.
  • Manual Activation: For manual control, connect the other part of the single pole double throw switch (the side that turns on in the momentary position) directly to the positive side of the bilge pump.
  • LED Indicator: To know when the bilge pump is working, especially on larger boats where the pump might not be audible, add an LED indicator. Connect the negative side of the LED to a ground wire that leads to your control panel, ensuring a source of ground. Connect the other side of the LED to the manual side of the bilge pump switch.
• Functionality:
  • With the above setup, when the switch is in the middle “off” position, the bilge pump is off, which is useful for maintenance.
  • In the “automatic” position, the pump is off unless water triggers the float switch.
  • The “manual” position allows you to manually activate the pump, ensuring you can drain the bilge completely if needed.
• Finalizing the Installation:
  • Once everything is in place, double-check all connections and seals.
  • Test the bilge pump to ensure it’s working correctly and that the float switch activates it at the right water level.