We don't have synonyms for rullock yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are bullock, mullock and rollock.
(n) :
Alternative form of rowlock. [(nautical, chiefly British) A usually U-shaped pivot attached to the gunwale (outrigger in a sport boat) of a boat that supports and guides an oar, and provides a fulcrum for rowing; an oarlock.]
(n) :
Alternative form of rowlock. [(nautical, chiefly British) A usually U-shaped pivot attached to the gunwale (outrigger in a sport boat) of a boat that supports and guides an oar, and provides a fulcrum for rowing; an oarlock.]