Underwater welding Diver welding an underwater pipe Commercial divers use welding tools to repair damaged underwater pipes ships or oil rig platforms The diver may use either dry welding techniques or wet welding Dry underwater welding is performed in a chamber filled with gas sealed around the structure to be repaired Wet welding techniques involve a cable connecting both the welding power supply and the structure Welders face a degree of risk including electric shock decompression sickness and explosions