Evening Republican, Volume 21, Number 309, Rensselaer, Jasper County, 4 January 1918 — Facts About Big Guns of the Navy [ARTICLE]

Facts About Big Guns of the Navy

turned to an exact fitless several thousandths ojjah ineh, then red*untfb expansion peivmtowitrto' be drawn on. It cools and adds strength not only by its thickness but by the grip of its shrinking. The first or inner tube has helical grooves to give rotation to the shell just as in any sporting rifle. Tremendous firing pressures between 15 and 20 tons per square inch cpmblnfed with acid gases and other products of* explosion cause erosion or ■wearing away and pitting of the grooves. Inner tubes must’ be renewed periodically. The life- of the gun, so-called, is about 150 shots. Since frequent target practices are held few years elapse before guns must be taken ashore and refubed. The total cost of retubihg a 14-inch gun is in * the neighborhood of $25,000. Besides the inner erosion constant shocks of explosion crystallize the whole steel structure. Crystallization of metal may be likened to the drying of cheese. At first the mass is relatively tough and elastic. After the • heavy punishment of protracted firing gun tubes weaken and become brittle. Microscopic examination reveals contraction and disintegration of metal iparticles just as cracks and crumbly sections occur in a cheese. Further

By Lieut. Fitzhugh Green of the U. S. S. Texas

sooner than is expected. Thej tins crack or burst. Pnjha Michiga » 15 -feAxff la ■EMncirgun Intake off ana fell on deck. On the next load the gun captain, having opened the breech to report “bore clear,” shouted “There ain’t no bore!” Fortunately no one was killed. \ The charge of a 14-inch gun is 385 pounds of smokeless powder put up in four silk-linen bags. The back end of each bag is painted red add contains about four ounces of black powder called the ignition charge. A brass primer similar to a'rifle cartridge except it has no bullet, ignites the black powder which in turn sets-fire to the smokeless powder. Contrary to popular belief there is no real explosion but a progressive burning of enormous rapidity. Vast volumes of gas at high temperature and pressure are produced; forcing the projectile out. A 14-inch shell weighs 1,400 pounds, is five* feet long, and contains a bursting charge. - Twelve strong men lift one with difficulty. Yet from the gun it can sink a’ battleship 12 miles away. It travels at the rate of 2,600 feet a second or a mile every two seconds. On striking it expends an energy of 65,687 foot-tons, or enough to transport a load of two tons to twice the height of Mt. Everest.