Abstract: Swimmers are detected in a given body of water by dispersing sensors throughout the water column. The sensors adhere to the swimmer and reflect acoustic energy. Acoustic energy is broadcast in the water and the swimmer is detected by the characteristic motion of the sensors clinging to the swimmer as detected by acoustic monitors. The sensors may also fluoresce and be detectible by optical monitors when a portion of the swimmer is above the water.

Abstract: A coating system for defouling a substrate, such as a ship hull, immersed in water or seawater for long periods of time comprises a conductive layer, an antifouling layer and a means for providing an energy pulse to said conductive layer. The conductive layer comprises polymers, such as carbon filled polyethylene, which are electrically conductive. The antifouling layer comprises polymers, such as polydimethylsiloxane, which have a low surface free energy. The layers are designed such that when the conductive layer is exposed to a pulse of electrical, acoustic or microwave energy or combinations thereof, said conductive layer separates from said antifouling layer.