DNV GL approves permanent underwater wet welding

Written by  Clare Nicholls

DNV GL and Subsea Global Solutions have completed an extensive joint research and development programme that will allow permanent repairs to be carried out by underwater wet welding on certain areas of vessels. Subsea Global Solutions’ network of coded welder divers will be available to perform these permanent repairs on a case by case basis utilising this procedure in suitable locations throughout the world in accordance with the approvals given by DNV GL.

Over the last two and a half years, Subsea Global Solutions welded in excess of 80 groove weld test plates underwater at depth in their training facilities in Miami, Florida, Long Beach, California and Terneuzen, the Netherlands. The non-destructive and mechanical testing of the plates was performed at the DNV GL lab in Hamburg, Germany. All data collected was shared between SGS and DNV GL during this procedure development programme.

In April, test plates were welded in the training tank in Miami Florida, with a DNV GL welding engineer in attendance. The non-destructive and destructive testing was again performed at the DNV GL lab in Hamburg. Welding of the plates as well as the testing was performed in accordance with AWS D3.6M:2010 Class A. The results were very positive with all welded test plates exhibiting metallurgical properties equivalent to permanent weld repairs performed “top-side” dry.