Introduction to Windlass

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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.  An anchor windlass restrains and manipulates the anchor chain on ship, 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. The windlass is mounted on a doubler plate welded to the forecastle deck.
The deck girders in forecastle space is increased. The deck beams pitch distance decreased to accommodate more beams. Four round pillars at four corners of the base of windlass doubler plate connect to the main deck plating to give continuity of strength to deck.
Technically speaking, the term "windlass" refers only to horizontal winches. Vertical windlasses are characterized by situating the capstan and/or gypsy above the deck and the motor and gearbox below. Vertical windlasses provide a 180° wrap of the anchor rode around the gypsy giving optimal chain control, minimizing slippage and jumping. Vertical designs are correctly called capstans. 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 fair leads). Vertical capstans use a vertical shaft, with the motor and gearbox situated below the winch unit (usually below decks).


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

Difference between Winch and Windlass

A winch is a machine usually powered by a hydraulic/electric power unit that is used to handle mooring ropes which are used too moor a ship while it is in port or to a buoy as in SBM/SPM operations. A windlass is a machine hydraulically actuated(steam powered in the olden days) used for letting go/hauling up of anchor.

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