Abstract: Single acting water hydraulic cylinders are used to raise floor platforms in aquatic environments. A first cylinder with a vertically raisable piston is positioned on one side of a platform while a second cylinder with a vertically raisable piston is positioned on an opposite side of the platform. Each cylinder controls two corners of the platform through wire ropes that pass through plural sheaves. The single acting water hydraulic piston can use city water pressure to raise the platform, while three way valves allow gravity to allow the platforms to be lowered. The platforms can include a grid type grate that can be used to raise and lower marine mammals (i.e. whales, dolphins, manatees, walrus), aquatic animals (i.e. hippo) and marine fishes (i.e. sharks, stingrays) from an artificial habitat such as as a park pool. The platform can alternatively be fired with pivotable pads for lifting vessels such as small crafts from slips.