What does it cost to replace a boat's bilge pump?
The automatic bilge pump on my 32ft sailing yacht has stopped working, although the manual pump still works. What should I budget for a replacement, including fitting, and should I change the float switch at the same time?
Answer
A straightforward electric bilge pump replacement usually costs £100 to £300 fitted, rising to £250 to £600 if the job includes a new float switch, wiring or discharge hose. For DIY replacement, budget £30 to £150 for a small or medium submersible pump, plus any switch, connectors and hose fittings.
Check the pump first
Start with the fuse, power supply, strainer and float switch. A blocked inlet or failed switch can give the same symptoms as a dead pump. Replacing a working pump leaves the fault in place.
Isolate the pump's electrical supply before handling its impeller or disturbing wiring, and provide alternative pumping while it is disconnected.
- Runs manually but not automatically: check the float switch or electronic sensor, its supply and the panel switch position.
- Hums but moves no water: inspect the impeller, strainer and discharge hose for debris, restrictions or an airlock.
- Completely silent: measure voltage at the pump with it switched on. Corroded connections can show battery voltage without a load but fail under load.
- Runs but pumps slowly: check battery voltage, hose condition and outlet obstruction before condemning the motor.
On larger yachts, switches at the chart table and helm may control separate manual and automatic circuits, or different pumps. Trace the wiring rather than assuming every pump has an automatic float.
Replacement parts prices
These UK retail ranges are budgeting guides, not quotations. Voltage, capacity and automatic controls affect the price.
- Small 12V submersible pump, about 500 to 800 US gallons per hour: £30 to £70, usually with a separate switch unless sold as automatic.
- Medium pump, about 1,000 to 1,500 US gallons per hour: £50 to £130.
- Larger pump, about 2,000 to 3,700 US gallons per hour: £100 to £250 or more.
- Separate float switch: £20 to £60; electronic switches can cost more.
- Connectors, fuse holder, cable and clips: allow £15 to £50 for a modest repair.
- Replacement discharge hose: allow roughly £5 to £15 per metre for common smaller sizes. Larger hose costs more.
Rule, Whale and Johnson Pump are established choices. A Rule 3700 is substantially larger than a compact everyday bilge pump, putting its replacement cost and hose requirements towards the upper end.
A remotely mounted diaphragm pump, such as a Whale Gulper installation, is a different proposition. Allow roughly £150 to £300 for the pump alone. A manual diaphragm pump may need only replacement valves and a diaphragm, so price a service kit before replacing the complete unit.