All About Engines

Engines for Ships 297 of every man who helped to shape the parts and put them together. A larger, more recent, and slightly less speedy vessel than the Mauretania is the Aquitania, belong- ing to the same company. She is 901 feet long over all, 97 feet beam, and 64 feet 6 inches in depth, dis- placing 53,000 tons, and having a speed of 23J knots. There are twenty-one double-ended boilers, 17 feet 8 inches in diameter and 22 feet long, with eight fur- naces in each. Though not constructed for a higher pressure than 195 lb. on the square inch, the shell plates are inches and the end plates inches in thickness, and the latter are supported by solid steel stays 2-g- inches in diameter. The total length of the tubes is more than fifty-four miles! They are arranged three abreast. Three of the Aquitania s boiler rooms are 78 feet long, each containing six boilers ; the fourth is 42 feet long and contains the remaining three boilers. One of the most interesting devices is the Stone’s under-water ash expeller, one of which is to be found in each stokehold. Below a grid in the floor is a hopper connected with a pipe, and when ashes are shovelled through the grid they are swept away by a flow of water which varies automatically with the quantity of ashes. Each expeller is capable of dealing with 15 tons to 18 tons of ashes per hour, which is more than three times the quantity that is likely to be produced. The boilers are supplied with forced draught directly to the ashpits of the furnaces by means of