I'm grateful to my friend Roy, who's from East Yorkshire and a keen fisherman, for telling me the story of ganseys, a word I'd never heard before (probably because I am neither from Yorkshire nor very knowledgeable about fishing). It's a dialect word for guernsey meaning sweater or jersey (odd that two of those words are names of Channel Islands).
Ganseys are hand-knitted, weatherproof jumpers traditionally worn by fishermen on the North Sea coast. They do, or did, more than keep the seamen warm, however. Each village had its own intricate pattern and therefore, whenever a boat sank and its occupants drowned, the bodies would be returned to the appropriate village. Sometimes the gansey was the only means of identification.
Knitting the gansey was a time-consuming labour of love. There are no seams in the garment which means that ganseys are knitted on four or more needles. There's an article about ganseys here and a short video clip of an exhibition, which shows a man knitting a gansey and talking about the garments here.