Underwater Welding – Wet Welding
In underwater welding, the wet welding process used for salvage operations is usually a simple underwater joining technique. The materials required are commercially manufactured shielded metal arc equipment and waterproofed electrodes. Minimal ancillary devices are needed. These include lighting, staging and hand tools. There are advantages to wet welding. The underwater welder can work freely on any portion of complex structures or on sections with restricted access, whereas other underwater techniques may encounter difficulties. Patching can be performed faster and at less cost because no time is lost in construction and installation of enclosures.
Because standard welding power sources and equipment are used, a wet welding job can be easily mobilized at remote job sites. Wet welding also allows more freedom of patch design and size of patch sections.
Wet welding with a stick electrode is done with similar equipment to that used for dry welding, but the electrode holders are designed for water cooling and are more heavily insulated. They will overheat if used out of the water. A constant current welding machine is used for manual metal arc welding. Direct current is used, and a heavy duty isolation switch is installed in the welding cable at the surface control position, so that the welding current can be disconnected when not in use.
The hazards of underwater welding include the risk of electric shock to the welder. To prevent this, the welding equipment must be adaptable to a marine environment, properly insulated and the welding current must be controlled.