Damages of the ship's hull underwater part, corrosion, buoyancy loss and other problems which require the solution. Ship repairing is an integral part of the life of any ship, it may be scheduled or urgent one. If the damages do not require the scheduled docking or the problem should be solved urgently, the underwater works, that is the underwater repair, are used. The underwater repair makes it possible to carry out the emergency works in a short time without necessity of docking. The list of underwater works includes the underwater welding and cutting.
The up-to-date underwater welding is performed more often by means of the following methods:
Welding in the dry environment, – in a dry deep chamber when quality of the welded seams are absolutely identical with the welded seams made ashore. But this is a labour-intensive process which requires two floating cranes and additional ships.
The dry deep welding, hydro-welding, - when the works are carried out in consistently dry gas environment, that is in special portable boxes. The similar semi-automatic underwater welding is made by an electrode wire. This method requires a tight fit to that place where the actual welding will be, that is tightness.
Special mixture of the inert gases is also necessary to displace the water from the chamber or box and to maintain a dry environment in them. An electrode wire which melts is moved with a specified speed to the welding head by means of the flexible hose. Such the underwater welding is monitored by means of the special control panel which is arranged above the water and it also has all necessary control and monitoring instruments. The dry deep welding is controlled and adjusted by means of the similar device.