 In the 18th century keelmen were identifiable by the blue bonnet many of them wore at work, later replaced by a sou'wester.In the 1840s they were described as wearing ""a peculiar costume, consisting of a large jacket, or rather doublet, with loose breeches, made very wide at the knee, and not descending further"".The trade of keelmen tended to be passed on from father to son, the son working as an apprentice on a keel until considered old enough and strong enough to be a crewman.