Gives criteria for welding structures or components under the surface of water. Includes welding in both dry and wet environments. Sections 1 through 6 constitute the general requirements for underwater welding while, sections 7 through 10 contain the special requirements applicable to four individual classes of weld: Class A - Comparable to abovewater weldings; Class B - For less critical applications; Class C - Where load bearing is not a primary consideration; Class O - To meet the requirements of another designated code or specification.