Abstract: Apparatus for underwater working, especially for heating, welding, torch cutting, cleaning and electrolytical coating of metal constructions with the aid of electrical current. The apparatus comprises a rotatable electrically conductive shaft (2) arranged on the frame element (1) of the apparatus and designed to conduct electrical current to the removable tip element (3) attached to the end of shaft, this tip element being such as heating bush, welding electrode, cutting, cleaning and/or coating disk.

Abstract: A method of conducting electricity in an arc welding device especially to an arc electrode (1), such as a welding, cutting, cleaning or electrolyte coating electrode, or to a device supporting such electrode, as well as an arc welding device to realize the method. The electrode (1) or the device supporting it is brought to a direct contact before the arc area with a flowing, preferably liquid, medium in contact with the power supply. The device for conducting electric current comprises a chamber (2) adapted inside the casing (6) and including flowing, preferably liquid, medium, which is in electrically conductive contact to the power supply and the electrode (1) or the device supporting it.

Abstract: A method and a tool for freeing of parts held fast, especially for freeing of bolts and nuts rusted fast under water. According to the invention an electric arc is created between the rotating endpiece (21) of the tool and the fast held part (1), with which the fast held part is heated and/or thermally cut, after which the fast held part can be freed from the fastened object.