Can qualifications gained in a fresh water tank qualify the welder for saltwater applications?

TWI Frequently asked questions

Yes; there is no stipulation in AWS D3.6M:1999 'Specification for underwater welding' (American Welding Society, ISBN: 0-87171-542-2) regarding qualification in salt or fresh water. However, depth limitations are specified. For example, if the qualification was gained at a depth of 6m (19.6ft), the maximum qualified depth would be 6m + 10m for carbon or low-alloy steel filler metal. The maximum depth qualified would, therefore, be 16m (52 ft).