Abstract: A system and method allows boats to operate air conditioners while positioned above the water level. A dock-mounted control unit has an inlet for lake or seawater, an inlet for fresh water, and an outlet to the raised boat. The fresh water is temporarily used to prime the system, after which the boat's A/C system can operate normally. After the system is primed, a valve on the control unit is used to close off the fresh water inlet, and the fresh water hose may be removed. A Y-valve (or two 1-way valves) provides two settings, one for ordinary, on-water operation, and the other for use in conjunction with the invention. The invention allows the boat's AC system to function as though it were in the water, allowing normal heat exchange with the body of water and thus, normal A/C while on a lift or hoist.