So I am assuming his primary work involved working the rigging (rope, pulleys, and sails) on a ship. I'm not sure what kind of ship, although I suspect commercial (there is a family story that he had gone to China once on a several-year trip and brought back dishes).
I've included his 3-part video shows plenty of rigging action on a traditionally rigged ship The Sørlandet to get an idea of what that looked like (warning, very technical):
Some more footage (vastly less technical) is from "World of Discovery - Tall Ships: High Sea Adventure", aboard The Danmark:
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