In order to tie off to a ring, handle, or provide a point to tie another line to,we might decide to use a loop knot. More than making temporary lanyards to tie off tools, loop knots can even be used to lower, or raise, personnel when the need arises.
The “King of Knots,” the bowline is one of the most useful knots used at sea. Excellent for forming temporary eyes into lines, it can nevertheless slip if not dressed properly. Try to resist using two bowlines to join lines together, the knot itself weakens the breaking strength of a line by 45% and when used as a bend it is likely to chafe. There are better knots for this purpose.
More secure than a standard bowline, a second turn helps to prevent the knot from spilling. Other variants of double bowlines exist, but this is the type taught by the Coast Guard.
This makes an excellent emergency boatswain’s chair. One loop provides a seat, and the second loop provides a backrest. The legs of a French bowline may be adjusted even after the knot is tied.
The knot historically used at sea for lowering an injured man from the rigging. A leg may be placed through each loop, and, if conscious, he may grasp the doubled up standing part while being lowered. If unconscious, he may be lashed to the standing part with the bitter end.