[1] In addition, for some decades after square sails were generally dispensed with, some yards were retained for deploying wireless (radio) aerials and signal flags.
When running directly downwind the yards are 'squared' (pointing perpendicular to the ship's centre line and to the mast).
In order to set and stow the square sails, the crew must climb aloft and spread out along the yards.
Almost all ships used in modern times are fitted with steel safety wires (sometimes erroneously called jackstays) along the yards to which sailors attach themselves using a harness.
Cargo-carrying and naval sailing ships were not so equipped and falling from the yard represented a real risk.
When coming into port, especially during the Tall Ships' Races many modern square riggers will 'man the yards'.
This phrase is used, both afloat and ashore, to indicate that the time of day has been reached at which it is acceptable, variously, to have lunch or (more commonly) to have an alcoholic beverage.
The actual time that the sun would pass a particular yard would depend greatly on the ship's latitude and heading, as well as the height of her masts, but the phrase seems to have originated in the north Atlantic, where, in summer, this would have typically been at about 11 a.m.
Instead of the usually quick death a hanging ensured ashore, the condemned man would have the noose placed around his neck, before the end of the rope was passed over the yardarm.
The last man hanged in this manner in the Royal Navy was Private John Dalliger in 1860, after stealing brandy and shooting two officers aboard HMS Leven.
[3] Another less common punishment, notably practised upon mutineers from the Dutch East India Company ship Batavia as well as captured pirates, was to be dropped or ducked from the yardarm.