3700 GPH Bilge Pump - 12V, Automatic (1-1/2" Hose)

These high capacity bilge pumps feature very heavy duty construction for both commercial and pleasure boat use. They are known for their trouble-free operation and reliability.
This pump has a 1-1/2" discharge outlet.

"Automatic" models pump when water is sensed in the bilge, and do not require a separate float switch.
"Non-Automatic" (traditional) models are activated by a separate float or panel mounted switch (sold separately).

• Completely submersible
• Rust and corrosion protected
• Silent, vibrationless operation
• Moisture tight seals
• Anti-airlock protection
• Compact, energy efficient, long life motor
• Able to run dry without motor burn-out
• Marine grade sealed wiring
• Easy to clean, snap-lock strainer base
• Stainless steel shaft
• Ignition protected
• CE and ISO 8849 certification
• 3-year limited warranty


Heavy on the technical side...

"Automatic" bilge pumps feature computerized operation based on the principle of impeller resistance. Float switches are not required.
The pump turns on every 2-1/2 minutes for about one second to sense for water in the bilge. If water is present, the pump will sense resistance and continue to run until the water is removed. Thereafter, it continues to check for water every 2-1/2 minutes. Power use in the checking mode for this 3700 gph pump totals only 0.76 Amp hours per day.

Note — The capacity of ALL centrifugal bilge pumps, regardless of manufacturer, is rated at "open flow" — with no hoses or resistance to impede output. In actual use, however, the work of lifting the bilge water out of the boat will decrease the output of the pump.
The higher the lift, the less the output.
For a typical larger bilge pump, expect an output decrease of approximately 5% per foot of lift.
For these Rule 3700 gph pumps, the tested output is about 87% of rated capacity when the maximum height of the discharge hose (not the outlet thru-hull) is 3 ft above the pump, and about 75% of rated output at 6 ft above the pump, and 62% output at 9 ft.
Pump output is further decreased by long discharge runs, any elbows in the discharge line, internal corrugations in the hose selected, etc.

If you have any doubts about the ability of any bilge pump to meet the requirements of your installation, it is always prudent (and not much more expensive) to simply purchase a higher capacity pump.