Pennsylvania class battleship

The "Pennsylvania"-class battleships, of the United States Navy, were an enlargement of the "Nevada" class; having two additional convert|14|in|mm|0|adj=on 45-caliber main battery guns, greater length and displacement, four propellers and slightly higher speed. They also had a relatively large secondary battery of convert|5|in|mm|0|adj=on 51-caliber guns, which was soon reduced when many of the guns' locations proved prone to wetness.

Design

The General Board having just finished the design of the Nevada class battleship moved on towards the seventh class of US dreadnought design issuing the 1913 design parameters, 12 14”/45 main guns, 22, 5”/51 secondary’s, convert|21|kn, and "Nevada"-class battleship armor. Minor rearranging of the secondary guns into fire control groups was designated. The strength of the General Board was again shown by demanding better ships from C&R Bureau and overcoming stagnation as it had done with the Nevada class battleships. The resulting ship now carried twelve 14”/45 by using triple turrets in all 4 positions that would be carried on in each succeeding class up to the Colorado class battleship when twin convert|16|in turrets would be used.

Underwater protection

The designers had noted the increasing size, range and explosive power of torpedoes as torpedo designs improved. In addition the design of the Davis torpedo was a concern. The Davis torpedo delivered an convert|8|in artillery shell in a gun barrel housed within a torpedo. As a result a series of caissons were built (actual sections of the hull as they were proposed for construction) and tested with both external armor and internal armor. The Davis gun could cause damage but the answer to the Davis gun was external armor, the external armor however greatly increased the amount of damage caused by a conventional torpedo. As a result of the caisson tests the Pennsylvania class battleships were designed with a 4 layer system of thin plating air space, thin plate, oil space, thin plate, air space, followed with an armored layer convert|9.5|ft inboard. This allowed the explosion to dissipate in the air space and deform the liquid loaded back plate. This section withstood the explosion of convert|300|lb of dynamite place against the hull of the caisson. This was considerably in advance of any navy at the time. [Friedman, Norman: U.S. Battleships an illustrated design history ISBN 0-87021-715-1 P114]

Engineering

As a result of improvements to steam turbine technology this class moved away from the unloved vertical triple expansion (VTE) reciprocating steam engine. Fore River was able to demonstrate better economic performance with geared steam turbine per ton of oil used. The only other class of engine used in battleship designs by the U.S. would be turboelectric drives much loved because of the amount of compartmentation this configuration allowed. The Pennsylvania Class introduced the 4 engine 4 propeller scheme use in all further U.S. Battleship designs.

Operation & updates

Serving in the western Atlantic in 1916-18, these ships visited Europe just after the November 1918 Armistice and were thereafter stalwart members of the Navy's Battle Fleet. Reconstructed in 1929-31, they received greater main battery gun elevation, tripod masts to support improved gun directors and modern aircraft catapults. The ships' secondary gun batteries were updated, as was protection against gunfire, aircraft bombs and torpedoes. Pennsylvania, assigned to duty as a fleet flagship, was given a greatly enlarged armored conning tower. Now capable of long-range gunfire in an age when the role of aircraft was steadily growing, the ships spent another decade in the Nation's battle line.

World War II

The Pennsylvanias were both present during Japan's December 7, 1941 attack on Pearl Harbor. USS|Arizona|BB-39|2 suffered a catastrophic detonation of the forward powder magazines when a bomb from a "Hiryū" Kate hit between and to starboard of Turrets #1 & 2, resulting in the most dramatic and costly casualty of the raid.USS Arizona sank after blowing up and breaking in two. USS|Pennsylvania|BB-38|2 was only lightly damaged, and she served in the Pacific throughout World War II. Fitted with a new secondary battery of twin-mounted convert|5|in|mm|0|adj=on 38-caliber guns in late 1942, she supported many amphibious invasions and was present during the world's last battle between big-gun warships, the Battle of Surigao Strait on October 25, 1944. A torpedo hit in August 1945 damaged her propulsion beyond economical repair, wrecking three out of four shafts. With other obsolete battleships, "Pennsylvania" was a target of the Operation Crossroads atomic bomb test in 1946 and was scuttled at sea two years later.

Construction

The Pennsylvania class included two ships, both built on the east coast:

USS|Pennsylvania|BB-38|3, built by the Newport News Shipbuilding & Dry Dock Company, Newport News, Virginia. Keel laid in October 1913; launched in March 1915; completed in June 1916.

USS|Arizona|BB-39|3, built by the New York Navy Yard, Brooklyn, New York. Keel laid in March 1914; launched in June 1915; completed in October 1916.

tandard type battleship

The "Pennsylvania" class was part of the "Standard type battleship" concept of the US Navy, a design concept which gave the US Navy a homogeneous line of battle (very important, as it allowed the Navy to plan maneuvers for the whole line of battle rather than detaching "fast wings" and "slow wings"). The "Standard" concept included long-range gunnery, moderate speed (21 kn), a tight tactical radius (~convert|700|yd|disp=s|abbr=on) and improved damage control. The other Standards were the "Nevada", "New Mexico", "Tennessee" and "Colorado" classes.

ource

Friedman, Norman:U.S. Battleships an illustrated design history ISBN 0-87021-715-1

References