RMS Titanic - Construction - Plating

Source: ANATOMY OF THE TITANIC - Tom McCluskie

Attached to the immensely strong internal frame were one-inch thick steel plates, each being 30ft length by 6ft wide; when riveted together, these formed the deck structure. To provide additional strength to the upper part of the hull, the thickness of the deck plating was increased to 1½ inches on the two uppermost decks - the Shelter and Bridge decks respectively.

The side shell plating, or outer skin of the vessel, at one-inch thick was also exceptionally heavy for a vessel of this type; however, as speed was not to be a consideration in the design of Titanic, the shell thickness became irrelevant. The shell plates were of identical size to those of the deck plates, this rectangular shape and the dimensions being the industry standard for steel plates supplied to shipbuilders by the manufacturers. Interestingly, modern shipbuilding steel plates, while of vastly different chemical composition to those available in 1912, are still supplied to this standard dimension.