The function of bilge pumps is to drain the accumulated water that accumulates inside the bottom of the ship. In most cases, there are several reasons why water accumulates in the bottom of the boat:
It may be rain or seawater on the deck of the ship; When cleaning the yacht, the rinse water that seeps in; Water leakage from the cabin cooling system into the bilge.
Generally on large yachts, cooling water will be discharged overboard through a complete drainage system, but on small boats, this water can generally only be discharged to the bilge; water may also flow into the bilge through some small pipe gaps, such as leaking shaft seals of straight shaft engines.
In particular, if the hull has cracks in the hull due to impact, or if the water pipe is ruptured due to the high temperature of the engine, a suitable bilge pump with a large enough flow rate can speed up the drainage so that it will not sink quickly, so as to buy time for repair or wait for rescue.
Where should bilge pumps be on a boat? At least one bilge pump should be installed at the lowest point of the bottom of the ship. Larger models of boats should have one in each closed compartment, and the drain port must be at least 20 cm above the waterline.
All bilge pumps should be located in a location that is easy for staff to operateso that they can check the condition of the pump and its float switch and remove debris from sucking around the pump. If the bilge pump is located in a hard-to-reach or hard-to-reach place, such as under the stern engine, consider relocating the bilge pump.
How and when should bilge pumps be activated? The bilge pump switch usually has "automatic" and "manual" configurations, when the water accumulates in the bilge reaches the set water level, the bilge pump float switch is automatically turned on, and when the water level is lowered, the float switch is automatically stopped; Generally, small boats only have hand pumps, as shown in the figure below on the hand pump button on the bridge.
It is importantto regularly inspect the area around the pump for debris that could cause the pump opening to become clogged. Especially new yachts need to be watched out for, as all kinds of construction debris – wood chips, fiberglass dust, styrofoam shards, epoxy shards, and even screws – can get into the bilge.
Check the function of the float switch regularly, as it may freeze or corrode over time.
The distribution of bilge pump drains should be concentrated above and away from wet bilges.
If the bilge pump is not on often, a small amount of water can be injected into the bilge water to check its function. This not only confirms the performance of the bilge pump's automatic switch, but also observes its drainage route.
Choose the right bilge pump for your boat The power rating of a bilge pump is determined by its pumping capacity in gallons per hour GPH. However, power is relative because the length, height, and type of pumping pipe can affect the pumping rate of the bilge pump. An industry rule of thumb is thata bilge pump is eligible if it can pump 60% of the approved power
If the discharge hose is tortuous, replacing it with a straight hose can increase the pumping volume by up to 30%. "A small flow pump is enough for a smaller boat", which may sound logical, but the opposite is true: when there is a hole in the hull of a small boat or other more serious marine accidents, the sea water affects small boats much faster than large ships.
Experienced shipowners use a double-pump strategy, especially when they are on long voyages: smaller flow (400-500 GPH) automatic bilge pumps are installed low in the bilge to cope with everyday situations such as rainwater leakage, while high-flow pumps (3,500 GPH) are installed higher for more severe situations.
