In hydro construction underwater works, there is, among other, the need for underwater cutting and welding of metal pieces. Such types of jobs are performed by trained professional and experienced divers. Special care should be given to the safety of the divers when performing such works. Prevention of electrocution, prevention of possible explosions, and prevention of burns and reduction of radiation effects should be ensured during welding. The diver must be equipped with adequate safety equipment (special gloves, protection glass, etc.).

Underwater cutting may be done with hydraulic and pneumatic tools using fuel gases. One of the ways to perform underwater cutting is using equipment for underwater cutting with ultra-thermal (5000oC) electrodes, using a torch for underwater cutting (Broco BR-22), or equipment for cutting (propane-butane with oxygen) which includes a special burner, reduction valves, dry irreversible valves and safety valves for oxygen and propane butane, gas nozzles various sizes, equipment for maintenance and double hoses.

Underwater welding involves connecting metal. It is most often used for connecting metal structures, repairs on ships, repairs of pipelines, etc. With underwater welding, equipment is similar or the same as with underwater cutting. Equipment used for welding may be used for underwater cutting, though with underwater welding electrodes and torch intended for underwater welding are used (Broco BR-21).