A centering device for a platform lift which includes a lifting mechanism for moving objects from a first to a second height. Each panel frame has a panel support and at least one panel clip to hold one of the shade panels. The system is configured such that acoustic energy generated by a non-explosive projectile as it impacts the water, enters the water, and sinks through the water, is sensed by the one or more acoustic sensors, and the processor is configured to process the acoustic energy sensed by the one or more acoustic sensors.