Adjustable loop knot for generations. Even when it’s used under extreme tension, a taut-line hitch can be adjusted to lengthen or shorten a line. This makes it valuable to anglers securing boats to docks, especially in saltwater where tide changes can mandate quick and easy line adjustments.
It’s best tied with lines having a rough feel, like fiber rope or textured lines. It may slip slightly when used with slick-surface lines.
The taut-line hitch works well for campers modifying tent lines to anchor pegs. It can even be used for locking aircraft to ground anchors. It’s an excellent way to tie down gear in a truck bed, or to secure decoy bags snugly inside a boat running across water. The taut-line is such a basic and trusted connection that space shuttle astronauts used it to fix the Hubble Telescope during a repair mission.