Hawser

A hawser is a thick, strong rope or wire rope used for the heavy work of securing and moving ships — chiefly mooring and towing. The word distinguishes these substantial, load-bearing lines from lighter cordage, and it is used for the ropes that take the real strain of holding a large ship against wind and tide at a berth or to a mooring buoy, and for the lines by which a tug or another vessel tows a ship. Hawsers may be made of natural or, today, synthetic fibre such as polyester, polypropylene or high-modulus fibres, or of steel wire, each chosen for its strength, weight, stretch and handling qualities.

In mooring, the hawsers are the main lines led from the ship to the shore bollards through the fairleads, worked by the mooring winches and capstans, and arranged as head lines, stern lines, breast lines and springs to hold the ship in position and stop it moving fore and aft or off the berth. To join a heavy hawser to the shore, a light messenger or heaving line is first thrown or passed across, and the hawser is then hauled over by it. In towing, a hawser connects the tug to the ship, and its length, strength and elasticity are important to absorb the snatching loads that arise as the two vessels move in a seaway.

Because hawsers carry very large loads, they are at the centre of the dangers of mooring and towing: a hawser under tension stores great energy and, if it parts, can whip back with lethal force through a snap-back zone, so handling hawsers demands care, good gear in sound condition, and standing clear of the danger areas. The condition of hawsers is inspected regularly, as a worn or damaged line is far more likely to fail. As the heavy lines that hold and move ships, hawsers are fundamental tools of seamanship.