Rule 3700 Automatic Bilge Pump - 12V - 55S

The Rule 55S 3700 GPH Automatic Bilge Pump is a heavy-duty, high-capacity water removal solution designed for commercial vessels and large pleasure boats. Unlike traditional pumps that require an external float switch, the 55S uses computerized sensing technology to detect water levels.

Automatic Operation & Efficiency

• Intelligent Sensing: The pump automatically turns on every 2.5 minutes for about one second to check for water. If it senses resistance against the impeller (indicating water is present), it continues to pump until the bilge is dry.

• Low Power Consumption: In its "water-sensing" mode, the pump uses only about 0.76 Amp hours per day, making it efficient for boats left unattended for short periods.

• Manual Override: A third wire allows you to connect a manual override switch or a warning light to monitor the pump's activity.

Key Performance Specifications

• High Flow Rate: Moves up to 3700 Gallons Per Hour (GPH) at open flow.

• Heavy-Duty Build: Features a stainless steel shaft, moisture-tight seals, and marine-grade blocked wiring to prevent corrosion.

• Protection Systems: Includes anti-airlock protection and an ignition-protected motor that can run dry without burning out.

• Installation: Uses a 1-1/2" (38mm) discharge outlet and requires a 25 Amp fuse.

Considerations Before Buying

While highly powerful, this pump has a high current draw of 15.5 Amps at 12V. It is best suited for vessels with robust battery systems. Some users have noted that the 2.5-minute cycling can drain smaller batteries if the boat is left unused for weeks without a charging source (like solar).

Comparison with Manual Version

If you prefer a traditional setup with a separate mechanical float switch, the non-automatic version may be more suitable.