Ship Winch Low-poly 3D model

A windlass is a machine used on ships that is used to let-out and heave-up equipment such as a ship's anchor or a fishing trawl. On some ships, it may be located in a specific room called the windlass room.

An anchor windlass is a machine that restrains and manipulates the anchor chain on a boat, allowing the anchor to be raised and lowered by means of chain cable. A notched wheel engages the links of the chain or the rope.

A trawl windlass is a similar machine that restrains or manipulates the trawl on a commercial fishing vessel. The trawl is a sort of big fishing net that is wound on the windlass. The fishermen either let-out the trawl or heave-up the trawl during fishing operations. A brake is provided for additional control. The windlass is usually powered by an electric or hydraulic motor operating via a gear train. Technically speaking, the term windlass refers only to horizontal winches. Vertical designs are correctly called capstans. Horizontal windlasses make use of an integral gearbox and motor assembly, all typically located above-deck, with a horizontal shaft through the unit and wheels for chain and/or rope on either side. Vertical capstans use a vertical shaft, with the motor and gearbox situated below the winch unit (usually below decks).

Horizontal windlasses offer several advantages. The unit tends to be more self-contained, protecting the machinery from the corrosive environment found on boats. The dual wheels also allow two anchors on double rollers to be serviced. 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).

It tends to be the case that smaller boats use capstans, and larger boats have windlasses, although this is by no means a hard and fast rule.