Rule-A-Matic® Float Switch

The Rule-A-Matic® Float Switch (Model 35A) is the marine industry standard for automatic bilge pump control, trusted by boaters worldwide to manage water accumulation in engine compartments and hulls. Designed for pumps drawing up to 14 Amps, this float switch activates automatically when water level rises, then shuts off when the bilge clears—eliminating the need for manual operation and ensuring your vessel stays dry even when you're away from the helm.

The latest Rule-A-Matic design incorporates a removable base for straightforward cleaning and service without removing the entire switch assembly. Its mercury-free snap switch mechanism has been tested to over one million operational cycles, delivering reliable performance across thousands of hours on the water. Marine-grade blocked wire resists corrosion in salt spray environments, while the 2-year manufacturer warranty reflects confidence in the product's durability. The 35A configuration handles standard 14-Amp draw specifications, making it compatible with most aftermarket and OEM bilge pump installations found on recreational and fishing vessels.

This switch suits weekend anglers running center consoles, fishing boats, and cabin cruisers as well as serious offshore operators who depend on unattended bilge protection during extended trips. The float-activated design works passively—requiring no electrical logic or manual switches—making it an essential failsafe for preventing engine-bay flooding, protecting electronics and structural integrity. Whether you operate in freshwater lakes or saltwater environments, the Rule-A-Matic handles the harsh conditions inherent to marine service.