Lattice masts, or cage masts, or basket masts, are a type of observation mast common on United States Navy major warships in the early 20th century. They are a type of hyperboloid structure, whose weight-saving design was invented by the Russian engineer Vladimir Shukhov. They were used most prominently on American dreadnought battleships and armored cruisers of the World War I era.
USS South Carolina, the first American battleship with lattice masts.
The collapsed foremast on the USS Michigan
The mast of a sailing vessel is a tall spar, or arrangement of spars, erected more or less vertically on the centre-line of a ship or boat. Its purposes include carrying sails, spars, and derricks, giving necessary height to a navigation light, look-out position, signal yard, control position, radio aerial or signal lamp. Large ships have several masts, with the size and configuration depending on the style of ship. Nearly all sailing masts are guyed.
Three-masted training ship Mersey
Main topgallant mast
This photo of the full-rigged ship Balclutha, shows the fore-mast, main-mast and mizzen-mast, as well as all the ship's standing and running rigging. The Balclutha is berthed in San Francisco, and is open to the public.
Roman two-masted ship, its foremast showing a typically strong forward rake