The part of the topgallantmast above the topgallant-rigging is called the royal-mast or royal-pole, and the continuation above the royal-rigging, if any, is the skysail-pole.  Answering to the topmasts on the three masts is the jibboom on the bowsprit, and in continuation of that the flying-jibboom.

The jibboom and flying-jibboom are generally in one spar, as are the topgallantmast, royal-pole and skysail-pole, but sometimes they are fitted into each other on much the same principle as a fishing-rod, and in some of the newer ships, bowsprit, jibboom and flying-jibboom are all one steel spar.

Crossing the masts are the yards.  On the mainmast we have, beginning below, main-yard, lower maintopsail-yard, upper maintopsail-yard, lower maintopgallantsail-yard, upper maintopgallantsail-yard, main royal-yard and skysail-yard; on the foremast we have the fore-yard, then the topsail-yards, topgallantsail-yards and royal; and on the mizzenmast we have a similar series of yards, beginning with the mizzen or crossjack.

Up to the close of the last century, in very old ships, there was no sail hung on this lower yard of the mizzenmast, it having been introduced only for setting the mizzen topsail; and instead of the gaff spanker we now have there was a huge lateen sail which extended some distance forward of the mast and worked under this yard.

This lateen was the crossjack.  When the gaff came in, the projecting corner of the lateen disappeared so as to make room for the sail hanging from this lower yard, and the yard took the name of the old lateen boom.

As representing, then, the after half of this huge boom, we have the modern gaff, set at the same angle as the boom used to be; and at the foot of the sail hung on this gaff, now called a spencer or spanker, from the original inventor, we have the spanker boom, the same sort of thing as we should call the mainboom were the vessel a fore-and-aft yacht.

Each mast is held in its place by stays and backstays.  The stays reach from the mastheads to the centre line of the ship forward; and the backstays come down to the sides of the ship, just behind the masts.

The stays and backstays are named from the mast-head from which they descend.  Thus the forestay comes from the foremast-head to the bows; the foretopmast-stay from the foretopmast-head to the bowsprit-head; the foretopgallant-stay from the foretopgallant-rigging to the jibboom-head; and the foreroyal-stay from the top of the royal mast to the end of the flying-jibboom.

From the bowsprit-head to the vessel’s cutwater runs the bobstay, generally of chain, which takes the pull of the foretopmast-stay; and from the bowsprit-head there hangs the spar known as the dolphin-striker, to give the purchase for continuing the pull of the foretopgallant and foreroyal stays round to the cutwater; so that really all the staying starts from the hull, as does the backstay-staying.