Occasionally it is found necessary to move them, perhaps to shift the centre of gravity to improve the fore and aft trim of the boat. This can only be done by a boatsmith, who will make a new set of riggers, or alter the existing ones.
Source: wiktionary
With some adaptive engineering by local metalworkers and boatsmiths, these light engines motorized several thousand riverboats, converting the classic dhows from cheap-but-slow to cheap-and-rapid inland water transport (Jansen et al. 1989).
Source: wiktionary
Imagine writing a scene set in a shipyard. As a deckhand struggles to repair a sailboat's mast step, a boatsmith looks over his shoulder and offers advice.
Source: wiktionary