An underwater pipeline is repaired by cutting away a defective section thereof and replacing the defective section with another length of pipe. The replacement is joined to the exposed ends of the pipeline by welded ball-and-socket joints. Those welds that it is necessary to perform under water are made...http://www.google.ca/patents/US4105887?utm_source=gb-gplus-sharePatent US4105887 - Welding apparatus and method
