Versatile hook and loop knots for high security 

The bridle shackle, mainly used for tethering livestock, can also be used as a general shackle; the mooring shackle is a versatile knot, especially suitable for mooring boats, because it can be adjusted at any time to make the length of the rope Adapts to changing water levels; Fisherman's Loop Knot, invented by Sir Isaac Walton in the 17th century, is a high-security loop knot that is also very popular.