Page:Popular Science Monthly Volume 88.djvu/731

 Using Triggers to Uncle Sam's Battle

How Science Has Made the

Launching of Dreadnoughts

Mechanically Perfect

By Robert Howard Gordon

��Launch ships

��The battleship "Arizona" ready to be "fired" into the sea by her

���THE launching of a great battleship involves the problem of releasing a ship from its ways without straining the shell. In the case of such great super- dreadnoughts as the New York and Ari- zona, the great length and enormous weight(jf steel necessitate unusual care in calculating the points where the strain can be relieved by additional ways. The "ways" are of two kinds, ground ways, which are immovable, and sliding ways, which move with the ship into the water. Ground ways consist of longitudinal timbers on either side of the keel, placed about midway between the keel and the turn of the bilge or under surface of the vessel. The sliding ways are similar and rest upon the grf)und ways, with a tliirk

��coating of stearin or grease between them, to facilitate the sliding motion of the hull, as shown in Figure i.

It was thought best in launching the Arizona to carry the ways as far forward as possible to gain additional length of sliding ways and conseciuently reduce the unit pressure. The extreme narrowness of the fore part of the shell necessitated the placing of three steel-plate slings under the ship, extending from side to side and lashed to the ship by heavy, wire rope as shown in Figure 2. The sj)ace between the slings and the hull of the boat was then filled with loncrete, which gave the ship a temporarlK in- creased width for\\ar(l. i'lie under por- tion of the shell, in llu' wake of the

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