Model of the “Great Britain.”
Her figure-head consisted of the royal arms, flanked with a beehive, two cog-wheels, a dove, square, and the caduceus of Mercury in bronze on a white ground, with a scroll above and below. Her anchor was on Porter’s newly invented patent, which had been satisfactorily tested in the Navy for three years.
Her designer and builder took no chances. She was put together as strongly as possible, and it was well that this was so, for in her eventful career she was altered so frequently and so much that had she not been excellently put together she would very soon have succumbed to ship surgery. Her keel was formed of iron plates varying from three-quarters of an inch thick in the middle to one inch at the ends.
The plates of the hull under water were from three-eighths to half an inch at the top, except the upper plate, which was five-eighths of an inch. She was clincker-built and double riveted throughout. Towards the bow and stern and in the upper strakes the thicknesses were reduced gradually to seven-sixteenths. The ribs were of angle iron six inches by three and a half, by half an inch thick at the bottom of the vessel and seven-sixteenths thick at the top. The boiler platform was of plate iron supported upon ten iron keelsons. The hull was divided into five compartments by water-tight iron bulkheads. The decks were of wood and consisted of the cargo deck, two cabin decks, and the upper deck.
The beams for the support of the decks were bars of angle iron about three inches across with an additional bar measuring five inches by half an inch riveted on the side. The beams were from 2 feet 4 inches to 3 feet apart. There were also between the angle-iron bars and deck planks a series of diagonal flat tension bars, forming a continuous horizontal truss from end to end in each principal deck; these bars were riveted to the angle irons at the crossings and at the ends in order to prevent horizontal straining. The engine-room was strengthened by adding nine additional double ribs and sixteen additional reverse ribs riveted to the original framing. Her three boilers were each 33 feet in length, 10 feet wide, and 24 feet high; she had 24 fires, 12 fore and 12 aft, with a total surface of fire-box of 288 superficial feet. Her chimney was 8 feet in diameter and about 45 feet high; her four cylinders were 7 feet 4 inches diameter with a piston-stroke of 6 feet. Her two condensers of wrought iron three-quarters of an inch thick were 12 feet in length. The main wrought-iron shaft measured 15 feet 9 inches.
The engines were after Sir Mark Brunel’s patent in the position of the cylinders, except that they were disposed at an angle of about 60 degrees. The pitch of the screw was 13 feet 2 inches and its diameter 15 feet. It was six-bladed, and the screw shaft was revolved by four endless chains.
The crew numbered one hundred and thirty all told and she could accommodate three hundred and sixty passengers. Her principal promenade saloon was 110 feet in length by 48 feet at the widest part and 7 feet high, and had two staircases at each end. Her first-class dining-room was 100 feet in length by 50 feet wide and 8 feet high, with staircases communicating with those of the promenade saloon. Seeing how far she excelled all other steam-ships, she well merited being called by the newspapers a “stupendous steam-ship” of “unparalleled vastness.”
Model of Engines of the “Great Britain.”
Her rig was as unique as her hull. She had six masts, of which only the second carried square sails, all the others being fore and aft rigged, and her one funnel was placed between the second and third masts. Five of her masts were stepped on turntables on deck so that they could be lowered and offer less resistance when going against a head wind. The lines of the ship were very fine, especially about the entrance from the forefoot. There was little of the “cod’s head and mackerel tail” style of build about her. She was admitted to be rather full amidships, for the accommodation of the engine, but was thought to approach as near the figure of least resistance as possible. The hull had a slight sheer and the vessel realised the expectation that she would be what sailors call “a dry ship.”