Rule Industries 51S 1500 GPH Automatic Bilge Pump 12V with Anti-Airlock

The Rule Industries 51S is a 1500 GPH automatic electric bilge pump engineered for high-capacity, reliable bilge water management aboard marine vessels. Operating on 12 Volts DC, this pump features computerized automatic operation — no float switch required. The pump activates every 2.5 minutes to sense for water; if water is detected, it runs continuously until the bilge is clear, then resumes its monitoring cycle. In automatic check mode, it consumes only approximately 0.35–0.50 amp-hours per day, minimizing battery drain.

Designed to keep bilge water at the lowest level possible, the Rule 51S activates at just 5/8" of water and drains down to 1/4" — far more responsive than a standard float switch system, which typically allows water to reach 2" before activating. The 1-1/8" (28.6mm) discharge outlet accommodates standard marine bilge hose.

Key Features:

• 1,500 GPH pumping capacity at open flow (12V DC)
• Computerized automatic operation — no float switch required
• 3-wire design allows manual override or indicator light capability
• Double-insulated long stack motor for cooler, more efficient operation
• Ignition protected — safe for use in gasoline-engine bilges
• Fully submersible construction
• No burn-out when run dry — safe if bilge runs empty
• Moisture-tight PTFE seals for long-term reliability
• Anti-airlock protection ensures reliable priming
• Double strainer non-clogging protection with snap-lock strainer base for easy cleaning
• Silent, vibrationless operation
• Heavy 5/16" stainless steel shaft for durability
• Nylon/fiberglass impeller for strength and corrosion resistance
• Heat-resistant acetal resin housing
• Marine-grade blocked wiring
• Rust and corrosion protected
• CE and ISO 8849 certified
• 3-year limited warranty

Specifications:

• Capacity: 1,500 GPH (open flow)
• Voltage: 12V DC
• Amperage: 4.8A
• Discharge Outlet: 1-1/8" (28.6mm)
• Operation: Fully Automatic (computerized sensing)
• UPC: 042237084965

The Rule 51S is a trusted choice for boatbuilders and boaters worldwide, delivering proven bilge protection with minimal maintenance and long service life.