windlass

windlass

windlass

A "windlass" is a machine used on ships that is used to let-out and heave-up equipment such as for example a ship's anchor or a fishing trawl.

An anchor windlass is a machine that restrains and manipulates the anchor chain and/or rope on a boat, allowing the anchor to be raised and lowered.

 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 heaves-up the trawl during fishing operations. 

A brake is provided for control and a windlass is usually powered by an electric or hydraulic motor operating via a gear train.

Horizontal or vertical

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 centre of gravity (important on boats), and also allow a flexible angle of pull (which means rope or chain can be run out to different fairleads).

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.

Ship_anchor_windlass_diagram