The Viaduct Works' Handbook

72 Size of Chain Ship’s Tonnage. in inches. 200 1re diameter 300 li » 400 1.3 18 » 600 18 » 800 11 1000 17 is » 1400 2 •>> 1800 91 28 2 The accompanying illustration represents part of the machinery made at the Viaduct Works in connection with a patent slip for raising a 2000-ton ship out of the water for repairs. The whole of the ma- terial and machinery for this apparatus was prepared here and sent abroad with all the tools and plant for erection. It consists of an in- clined plane 1075 feet long at an inchnation of 1 foot in 24 feet, fitted with four lines of rails; the gauge of rails out to out is 30 feet; to be laid sufficiently far into the water to admit of a cradle or carriage 250 feet long being lowered thereon by means of a chain into the water underneath the ship intended to be raised, when the ship is floated immediately over the cradle and hauled in towards the incline until it touches the cradle, upon which are fitted suitable sliding wedges and machinery to work them from a platform extending the whole length above water on each side of the inclined plane and communicating with land. When the ship is securely wedged on the cradle, the chain by which the latter is attached to the land is hauled in, pulling with it the cradle and ship upon it completely on to dry land, by means of a powerful windlass or crab, which forms the subject of the illustration referred to. The crab is worked by a pair of 25 H.P. horizontal engines and boilers. The main lifting chain is of the stud-link class, 3 inches diameter, and weighs upwards of 70 tons. The rails forming the ways for cradle to run upon are of massive cast-iron in section, about 12 inches wide at • base and 4 inches at top. The central pair of lines are placed as close together as convenient, and the outer pair as above named 30 feet apart. The rollers or wheels upon which the cradle travels are about 2 feet diameter, and placed about 3 feet apart throughout its entire length.