How to stay put with a snubber
At its most basic, a “snubber” is a short length of non-stretchy cordage attached to the anchor chain and to a strong point on a yacht, with the aim of taking the load off the windlass or to stop the chain rattling on the bow roller. A windlass is not designed to take snatch loads, nor, typically, is the deck to which it is attached.
More commonly, the term describes a long piece of cordage that cushions the boat from snatch loading. Typically, nylon rope is used for a snubber. Nylon stretches about 40 percent at breaking point, but about 10 percent is considered the safe working load limit (WLL). The more cycles above 10 percent of WLL, the shorter the life. Nylon’s elasticity is a function of weight—the thinner (less weight) it is, the easier it will stretch—and by measuring weight per meter it is possible to calculate extension.
Nylon is not the only cordage you can use as a snubber. Polyester is also suitable, although it lacks the degree of elasticity of nylon, so you will need longer lengths to achieve the same performance. In the unlikely event you cannot source nylon, then polyester is an alternative, but nylon is the most suitable.
Snatch loads are all about energy—the energy of a moving yacht. If a yacht sails at anchor, it develops momentum, or kinetic energy. Energy is measured in joules and is defined as:
Energy, joules = 0.5(mass, weight, kgs) x (velocity m/sec)2