To alleviate the risk of shock associated with lifts, Prof. Gary Kurtz and an engineering student at Purdue University built the only known pneumatic boat lift. It is based on a standard friction-drive lift, but pneumatics rather than electricity powers it. The rig uses a standard air compressor located about 60 ft from the dock, though it has been tested with the compressor 250 ft away. A 1.25-in. ID water line sends compressed air to the dock where it feeds into a three-position return-spring, manually operated directional valve. Two lines from the valve power a pneumatic motor that has its shaft connected to the boat-lift’s friction wheel. The lift can raise a 3,000-lb boat and costs about $700.

An air-powered lift takes boats out of the water without risk of electrical shock.