Wet Underwater Welding

• During wet underwater welding, the welder and the structure are surrounded by water. Most welders use manual metal arc welding when performing wet underwater welding. Hoses and cables connected to the surface provide power for wet underwater welding.
  
  

Hyperbaric Welding

• Hyperbaric welding occurs in a sealed chamber built around the structure. The chamber is filled with a mixture of helium and oxygen gas. Workers usually use the gas tungsten arc welding process during hyperbaric welding.
  
  

Considerations

• Hyperbaric welding allows workers to create higher quality welds, since illumination is better and the metal is not surrounded by water during welding. However, wet underwater welding costs less, requires less equipment and can be performed in areas that could not be reached with hyperbaric welding.
  
  

Risks

• Underwater welding places workers at risk of electric shock. Pockets of gas can also build up and explode. Inspecting underwater welds is also difficult, making undetected defects more likely.