Dismasting

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Dismasting, also called demasting, occurs to a sailing ship when one or more of the masts responsible for hoisting the sails that propel the vessel breaks. Dismasting usually occurs as the result of high winds during a storm acting upon masts, sails, rigging, and spars.

Over-compression of the mast due to the rigger being over-tightened, as well as g-forces caused by wave action and the boat swinging back and forth, can also result in a dismasting. Dismasting does not necessarily impair the vessel's ability to stay afloat, but rather its ability to move under sail power. Frequently, the hull of the vessel remains intact, upright and seaworthy.

Modern masts are usually made of aluminum, carbon fibre, or other high-strength materials. These masts are subject to huge forces and tensions during high wind, large seas, or racing situations, and it is not uncommon even today for modern masts to be lost.

The dismasting of a vessel can be immediately life-threatening as a consequence of a mast falling atop crew or passengers. For example, two deaths and several injuries occurred in Hawaii owing to two different dismastings. These incidents resulted in more stringent enforcement of safety standards for commercially operating sailboats.^[1] A dismasting can also endanger lives after the mast has fallen. The reason is the broken tangle of mast, rigging, and sails usually remains attached to the vessel owing to the rigging. If waves bash a large broken mast section against a relatively thin modern hull, the entire vessel can be lost.^[2] Therefore, it is frequently imperative for crew members to go out of the relative safety of the interior and into the same stormy conditions that caused the dismasting. There they must cut away the mess without becoming entangled in the lines, and without getting blown or knocked off the deck into the sea. To assist in this effort, many sailboats will carry a large pair of bolt cutters, extra hack-saws, or hydraulic cutters for just such an emergency.^[3] Crew also have to go onto deck to confirm there are no ropes or lines being dragged in the water that could wrap around a propeller before starting any internal combustion engine as a secondary means of propulsion.

Dismastings are rarely life-threatening after the initial event and the broken mast is cut away. However, dismastings appear to have contributed to the loss of life at sea as a consequence of crews abandoning an otherwise perfectly seaworthy vessel in favor of a life raft. This has led to a sailing adage to always “Step up into the life raft.” ^[4] In other words, to never abandon the sailboat unless it is confirmed that it is really sinking.

After a dismasting, the crew might jury rig, or fashion, a makeshift mast(s) and sails from salvaged and spare materials carried aboard. This would allow limited propulsion and navigational control. If the ship managed to make landfall near forests with suitable wood, new masts could be constructed from the locally available material. The masts of a sailing ship should be regularly inspected and replaced if necessary due to storm damage and normal wear. Most ocean-going ships would carry a large supply of rope, sailcloth, and even spars for ordinary and extraordinary repairs. It is often possible to use part of the broken mast to create a jury rig. Spinnaker poles and mizzen booms may even be used. A man-of-war would expect to carry out additional repairs due to battle damage.