Rigging
Running rigging is often subject to parting, especially during bad weather, or when attempting to carry too much sail in a strong wind. For instance, the brace on the weather side is under a considerable strain, and its parting would allow the entire yard to swing free, a rather ugly prospect for a spar up to 30 meters long. In general, for each line there is a procedure to a) reduce the forces at play, b) use other lines to bring loose items under control, and c) run a replacement line (retying is not usually an option, since the knot will not fit through the blocks). The most critical lines will sometimes have a backup in the form of a "preventer" line serving the same function.
Standing rigging is a structural element that holds up the masts, and loss of standing rigging puts them at risk of being sprung (cracked) or simply snapped off. By the end of the age of sail, most stays had preventers, and warships equipped themselves with "rigging stoppers" or "fighting stoppers", small lengths of rope arranged so they be attached to shrouds quickly and tightened.
In the days of wooden construction, sprung masts were a serious problem, because their structural integrity was compromised, and the next gust of wind could easily bring them down. Upper masts were usually just replaced by spares carried for the purpose. The usual recourse for the lower mast was to "fish" it by lashing a special set of spars to the mast along the cracked area.
If the mast was gone altogether, it had to be replaced with a jury rig assembled from whatever spars were available.
Read more about this topic: Sailing Ship Accidents