What is the maximum height above waterline for cooling water to exit the thru-hull?

The maximum height above the waterline for cooling water to exit the thru-hull is determined primarily by ensuring effective cooling and preventing air from entering the sea water system, which can lead to issues such as overheating of the equipment.

Choosing 8 inches as the correct height strikes a balance between adequate cooling and maintaining a reliable system. It minimizes the risk of siphoning effect or insufficient water flow while also ensuring that the exit point is not excessively high, which could demand more energy to pump water effectively. This height allows the system to function efficiently during normal operational conditions, accounting for variations in water levels due to tide changes or boat movement, which can affect the effective flow of cooling water.

The other choices present heights that may either be too high, risking the potential for air ingress, or not providing sufficient clearance to avoid blocking the discharge path. Keeping the exit 8 inches above the waterline helps to optimize performance while adhering to safety and operational standards in marine environments.