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.
The dismasting of a vessel can be immediately life-threatening as a consequence of a mast falling atop crew or passengers.
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.
[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.
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.
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 their wide beam that causes their sails to remain closer to vertical in the face of strong wind.
G-force loads is one of the less common reasons for a dismasting, however, it is still a real risk for both types of sailing vessels.
The mast will come to a sudden stop when the vessel returns to near upright when the wind fills the sails again.
This violent rocking in turn translates to extreme g-force shocks on the rigging caused by the weight of the mast swinging back and force.
At roughly the same moment the wind will fill the mainsail and a shock load will transfer into the mast and rigging and a dismasting might occur.