Boilermakers

This is a description from a current trade site and is just as applicable to our ancestors, with alowances made for modern industry. The original occupation stemmed from making - boilers (!) and they were rivetted together, so the boilermakers were also rivetters.

Boilermakers are involved in building very large tanks, heavy pipe work and pressure vessels for nuclear power plants, refineries, and chemical manufacturers and in the ship construction industry. 
As a Boilermaker, one assembles, erects and maintains boilers, tanks pressure vessels, heat exchangers, calandrias, pollution control systems, furnaces, condensers, water towers, penstocks and scroll casings using hoisting, rigging, welding equipment, tools and hardware as required by drawings, specifications and the applicable codes and standards.