Whether you are an avid boater or strolling along the dock looking at the vessels, it appears as though boats spit out water continuously. The flow of water from the inside of the watercraft to the outside is not necessarily constant. Keep in mind there are multiple systems that utilize raw water to operate. Raw water is fresh or saltwater pulled from the water in which the vessel sits. Understand why boats spit out water. 

Bilge Pump Water Flow

One of the most critical components of a vessel to help avoid it from sinking is a bilge pump. A bilge pump removes water that has accumulated. The water comes from rain or sea spray on the decks, from small leaks, or washing the boat down. 

The purpose of the bilge pump is to remove water that has accumulated below the deck. These pumps are electric and contain a float which activates the device when the water level is high. 

Bilge pumps operate by sucking water up from the bilge through a hose and dispersing out the vessel’s side. One of the reasons boats spit out water is because of the bilge pump.  

Raw Water Air Conditioning Systems

Nobody wants to sit in the interior cabin space of a hot vessel from the sun baking down on the surface above. 

Air conditioning units fitted on large vessels operate by utilizing raw water. The air conditioner functions by drawing water in from the outside of the vessel. Raw water draws the heat from the air conditioning coils before dumping the heated water back out into the body of water. 

A vessel with a constant and steady flow of water from the inside to the outside is most often the boat’s air conditioning system in operation. 

Livewell Pumps For Bait

The purpose of buying or catching live bait is to use the fish or crustacean while it remains active to draw more strikes. Anglers do not find as much success by utilizing dead bait.

A livewell pump draws water from the outside of the vessel into a tank holding the bait. Oxygenated water is constantly pumped in, and to avoid the well from overflowing, the excess spill out over the side and back into the body of water. 

Remember, the water will only flow out the side of the vessel when the livewell is in operation. Once the pump is turned off, the water stream will cease. 

Engine Cooling Systems

The prevention of overheating inboard and outboard engines lies heavily on raw water. Like an air condition unit, the purpose of the water is to draw heat away from the engine,

Keep in mind, the discharge of the inboard and outboard will appear different. Inboards pump water out the side or stern of the vessel and are most often mixed with exhaust. Outboard motors, on the other hand, function differently. 

As obvious as it may sound, the outboard motor is attached to the outside of the boat compared to inboards inside the vessel. Outboards are equipped with a discharge port whose purpose is to show the operator that water is flowing; therefore, overheating will be avoided. 

Much like the livewell, the water will only discharge when the motor or motors are running. 

Now You Understand Why Boats Spit Out Water

As you can see, there are numerous reasons why boats spit out water. Engineers have done an excellent job of utilizing the liquid in which the boats sit for multiple functions and, most importantly, cooling. The next time you’re walking the dock and friends or family look puzzled as to why water is pouring out the side of a boat, you can educate them.