Rule 12V Auto Submersible Bilge Pump RM800B — 800 GPH, AutoSense Intelligence, Threaded Discharge

The Rule RM800B is a 12V auto submersible bilge pump that delivers 800 GPH with AutoSense Intelligence for automatic, efficient water removal and reliable backup protection.

Compact yet powerful, the RM800B is engineered to remove bilge water quickly while conserving battery power. Built on Rule's Rule-Mate platform, this pump improves flow by about 10% over previous generations without drawing more amperage. It combines an automatic sensor, thermal protection, anti-backflow features and a threaded discharge for straightforward installation in cramped bilge compartments.

How does the AutoSense Intelligence protect my boat?

The RM800B’s AutoSense system monitors bilge water and starts the pump at roughly 2 inches, shutting off when levels fall to about 3/8 inches to prevent unnecessary running. If the sensor becomes obstructed, the pump automatically switches to a timed cycle mode to prevent continuous operation and conserve battery.

• Automatic activation at ~2 in. water level
• Shuts off at ~3/8 in. for controlled dry-out
• Backup 2.5-minute cycling if sensor blocked
• Reduces risk of unattended flooding

What installation steps should I expect with the threaded discharge?

Installation is designed to be fast and accessible: the RM800B uses a threaded discharge that mates with common hose fittings for a secure, leak-resistant connection. Its compact footprint lets you fit the pump into tight bilge locations and route discharge plumbing with minimal bends.

• User-friendly threaded discharge for standard fittings
• Compact body fits small bilge wells and narrow spaces
• Simple wiring to a 12V source with basic marine connectors
• Reduce installation time compared with larger pump assemblies

What reliability and safety features are built in?

The RM800B includes thermal cut-off protection to prevent overheating and hidden vents that lower the chance of airlocks, both extending pump life and reducing maintenance. A backflow prevention system keeps expelled water from returning to the bilge, maintaining pump efficiency between cycles.

• Thermal cut-off prevents motor burnout
• Hidden vents minimize airlock occurrences
• Backflow prevention preserves pumping efficiency
• Durable construction for marine environments

How much performance can I expect from the 800 GPH model?

The RM800B moves up to 800 gallons per hour under optimal conditions, roughly 10% higher flow than prior Rule-Mate designs at similar amperage. That balance of flow versus power use makes it effective for routine bilge management and emergency water removal while limiting battery drain.

• Rated capacity: 800 gallons per hour
• Improved flow with unchanged amperage draw
• Effective for both slow leaks and heavier ingress
• Suitable for small-to-medium sized vessels

Who is this for: The Rule RM800B is aimed at boat owners, cruisers, and marine technicians who need a dependable automatic bilge solution in a compact package. It suits small cabin cruisers, dayboats, tenders and other vessels that require efficient water removal without complex installation. Choose the RM800B if you want hands-free bilge management with smart sensing, built-in safety features, and reliable flow performance that protects your boat and preserves battery life.