On the first of the series of the present report, the authors performed theoretical analysis of the method of simultaneous welding carried out by multiple welders, and verified that the present method will reduce the degree of constraints through increasing the number of starting points of welding operation.
On the second of report series, the authors performed measurements of experiments tried out on bottom shell blocks of an ore carrier of D. W. 21, 000 ton class, with a view to confirming the occurrence of the same phenomenon on actual ship's blocks as that theoretically determind to occurr.
The result of the present experiment shows that as the number of starting points of welding operation is increased the degree of constraints to occurr at commencement of welding will be reduced, and also that as the occurrence of sliding phenomenon of constraint members, the degree of constraint will be rapidly reduced.