grinder
n.— «Some, like Chris Brittle, are called grinders—muscle machines who crank huge winches. Others are trimmers, fine-tuning the line of every sail. Each time we change course, everyone leaps to the nearest rope or winch handle and heaves with all their might.» —“The America’s Cup: the barmiest race of them all” by Robert Hardman Daily Mail (United Kingdom) May 12, 2007. (source: Double-Tongued Dictionary)