What type of tanks are specifically designed to remain full of liquids?

Sea water compensated fuel storage tanks are specifically designed to remain full of liquids, primarily to maintain stability and balance during operations. These tanks are particularly utilized in marine applications, where the buoyancy and stability of the vessel depend on the weight distribution of the fuel storage. By compensating for the weight of fuel consumed with seawater, these tanks help to ensure that the vessel remains properly balanced as fuel levels change.

This design allows for a continuous and controlled supply of liquid, reducing the risk of air pockets and ensuring that the pump systems operate efficiently. This contrasts with other types of tanks, which may serve different purposes or may not be designed to remain full. For instance, potable water tanks are used to store drinkable water but are not inherently designed to remain full under changing conditions of use. Fuel storage tanks can be designed to hold liquids, but they may not require constant fullness as they are primarily concerned with fuel reserve and dispensing. Holding tanks, on the other hand, are typically not meant to remain full at all times as they might be used to store waste or excess liquid temporarily.