cat

A cat is a mechanical assembly mounted on a ship's side that hoists the anchor from the water and secures it against the hull. It consists of a block and tackle, or on larger vessels, a powered winch, fitted to a projection called the cathead that extends from the bow. The cat lifts the anchor flukes clear of the water and holds them against the ship's side in a stowed position during transit, keeping the anchor from swinging and damaging the hull or rigging.

The term comes from the cathead itself, a wooden or steel beam bolted to the upper part of the bow, typically 15 to 25 feet from the stem. Older sailing vessels used cat tackle with multiple blocks, requiring crew to haul manually in coordination. Modern ships employ powered cats, either electro-hydraulic or steam-driven, capable of lifting anchors weighing 10 to 50 tons or more depending on the vessel class. The cat winch is separate from the main anchor windlass, which initially breaks the anchor free from the seabed; the cat then secures it for sea.

Placement and operation

Cats are positioned one on each bow, port and starboard. The anchor is guided into the cat by a fairlead, then raised until the flukes nest against a cathead stopper or carrick bit. On larger cargo ships and tankers, the cat is often hydraulically powered and operated from the bridge or a control station, allowing a single operator to manage both anchors. The tackle must be strong enough to hold the anchor's full weight if the ship pitches heavily in a seaway.

Wear and fatigue are the primary failure modes. The block sheaves, rope or wire, and fastening bolts experience cyclic stress during repeated anchor operations. Salt spray accelerates corrosion of steel components. A corroded cat can slip or fracture without warning, risking the loss of an anchor in deep water or, worse, allowing it to drop onto the deck or into the sea during maneuvering. Routine inspection of cat tackle, including block condition, wire or rope integrity, and bolt tightness, is a standard shipboard maintenance task.

The word cat appears in other maritime contexts, notably in catfish (a type of net) and in old compound terms like cat-harping, but the anchor cat is by far the most common usage in modern shipyards and vessel operations. Its design has remained conceptually unchanged for centuries, even as materials and power sources have evolved from wood and manpower to steel and electricity.