What are some of the tasks an experienced sailor does on his sailboat that involve knots before retiring for the night? He is on the open sea.
During the day’s sail, the skipper will perform several sail adjustments, using temporary knots, twists, coils, etc. They are temporary because they need to be changed from time to time, so must be easily undone and modified. Before setting the self-steering gear (I assume there is one), the skipper must check all these knots—slipknots, bights, etc.—and make sure they are all permanent for the night—the halyard, which might have been simply cleated, should be secured with a bight; the boom vang must be secured, etc., and all jib sheets. Any figure-eight knots should be checked to make sure they aren’t grannies, etc. Loose lines should be neatly coiled. No slip-knots in any of the settings. Any cleats with line on them should be locked, if that feature is available. Anchors should be stowed below, but an emergency water-anchor (a cone of canvas) should be ready on deck with a strong line attached by a bowline, in case of sudden seas.