A fully-stocked modern 36-40 foot powerboat can contain more than a dozen pumps that carry out an array of tasks. Sump pumps are commonly used to move shower, sink or sump water from the utility to storage tanks in the vessel. The water will be pumped into a gray water waste tank, which can be emptied out at the dock, using another pump.
These utility pumps typically come with a built-in pressure valve that shuts down the pressurizing system when the pump reaches full pressure. Most marine pumps that move these slurry liquids are diaphragm pumps. These products contain an internal chamber with an entrance and exit, and a membrane that expands when the chamber draws in water.
Bilge water has been a challenge for sailors throughout history, despite the improved sealing of modern boats. It is the water that stays on the boat and does not drain off the deck or through the scupper, typically due to rough seas, rain, or untreated leaks in the hull. Mast drip, window leaks, excess condensation, and corroded hose pipes can also contribute to bilge water accumulation. This can lead to water pooling under the floorboards, in storage areas, and even below the engine.
Most modern boats have a network of pumps to remove bilge water from different parts of the bilge. Rule centrifugal bilge pumps are the most popular, but their shape and design limit their mounting options, making them ineffective for removing all bilge water. They are designed to remove copious amounts of water rapidly, up to 4000 gallons per hour, but by design, leave about ¾ inch of water behind. Remember that they are not intended to remove all the water due to their overall design.
The Rule Dry Bilge Pump is an effective and reliable solution to keep a boat’s bilge clear of water. It features a diaphragm pump, allowing it to self-prime up to 9.5 feet (3 m) and create a vacuum that thoroughly removes most of the water from the bilge.