Anchor windlass

The unit tends to be more self-contained, protecting the machinery from the corrosive environment found on boats.

Vertical capstans, for their part, allow the machinery to be placed below decks, thus lowering the center of gravity (important on boats), and also allow a flexible angle of pull (which means rope or chain can be run out to different fair leads).

This would occur if the windlass brake has slipped (in a storm, for example) and the cable has reached "the bitter end".

[1] It originally applied in sailing vessels where the cable was a rope, and the windlass or capstan was powered by many sailors below decks.

The wheels on either a vertical or horizontal windlass provide for either chain or line to be engaged.

[citation needed] It is important that the chainwheel match the chain size (i.e. the link pitch) closely.

Even a small difference in link size or consistency can cause undue wear on the chainwheel and/or cause the chain to jump off the windlass when the winch is operating, particularly during payout, a runaway condition sometimes referred to as "water spouting" should it occur at high speed.

[citation needed] Nowadays, especially on large tankers and cruise ships, the windlass may be split into independent port and starboard units.

[clarification needed] The mechanical advantage of a windlass is derived from the pulling force being multiplied by wrapping the rope around the drum.

While many modern windlasses require an external power source, many remain manually driven in the same manner as most sailing boats' winches for sheets.

It consists of a turnbuckle, usually attached at the base of the anchor windlass, and a metal hook with two curved fingers that grab one link of a chain.

A devil's claw is often used on merchant ships because it is lighter and easier to manage than other types of chain stoppers, such as a pelican hook.