A cathead is a large wooden beam attached to the front of a sailing ship which aided in lowering, raising, and supporting the ship's anchor. In addition, it prevents damage to the ship's hull by keeping the anchor at a safe distance from it. During the heyday of this hull member, these beams were usually fitted in pairs, one on either side of the ship, and were often embellished on their outer ends with carvings of lion or cat heads. Although not documented, these decorations are thought to have been the source of the name. The beam was equipped with a pulley or sheave at either end over which the anchor rope passed and which facilitated the raising and lowering of the anchor.
Anchors of one or another description have been used since antiquity to provide a temporary mooring point for vessels of all sizes. The anchors on the wooden hulled sailing ships of old were typically kept suspended from a rail in the bow, or front, of the ship while underway and lowered to the sea bed to provide stable mooring for the ship when at rest. These anchors were fairly cumbersome items often weighing in excess of 2,000 lbs. (900 kg), thereby making their lowering and raising no simple task. On most large sailing vessels, a hull member known as a cathead was used to ease this task and to protect the ship from damage by the swinging anchor when it neared the hull on retrieval.
Consisting of a stout timber beam attached to the bow of the vessel and projecting over the side at an angle, the cathead allowed crews to lower and raise the anchor away from the hull with an element of mechanical advantage. These beams were typically fitted in pairs, one on either side of the ship's bow, and attached to lateral spars known as cat beams. The outer ends of the cathead were typically carved with ornate lion or cat head figurines. Although the exact origin of the cathead name is not known, these carvings were almost certainly the source of the cathead name.
The cathead was generally equipped with rotating pulleys or sheaves on both ends. The anchor rope and chain passed from the deck, through an opening in the ship's side known as a hawse pipe, and over these sheaves. This arrangement served to not only ease the passage of the anchor but to keep it away from the ship's side. Once the anchor reached the cathead, it was secured to the rail of the ship for the next leg of the voyage.