HISTORY

At the time the catapult was installed, the

original fixed launch ramps were removed from the turrets.

Modernization

The Washington Conference concluded

on February 6, 1922, with the signing of

an agreement amongst the main naval

powers of the world at the time, Great

Britain, the USA, Japan, France and Italy. It ended the race to build battleships

and set rules for the category, as it did for

destroyers and aircraft carriers. With respect to battleships, and the pretty much

obsolete category of battle cruisers, rules

were applied to the construction of new

ones and the modernization of older vessels and their replacements. One of the

main points of the agreement was the limiting of the service life of battleships to

twenty years. It stated that the possibility

of their replacement was an option past

this timeframe, from the time of its entry into service, and its construction could

begin then. It went on to further not allow

the possibility of increasing side armor,

the number of main armament or the caliber. Improvement of protection against

‘air and submarine’ attacks was permitted,

limited to an increase in displacement by

3,000 tons. All of this meant that the US

Navy had 17 battleships at its disposal,

beginning with the oldest, the USS Florida and the USS Utah, in service from 1911,

and ending with the most modern Colorado Class threesome, completed between

1921 and 1923. All battleships were to have

undergone modernization at the midpoint

of their expected operational career span,

the depth of which was dictated partly by the technical state of the ship and

the current US Navy standards in force,

with emphasis on power plants, main gun

range, anti-aircraft defenses, increasing

deck armor against air attacks and direct artillery hits, as well as against explosions below the waterline, specifically

against mines and torpedoes.

USS Arizona during its reconstruction and modernization in 1930 (photo: U.S. Naval History

and Heritage Command).

to 32.38 m. The increase in displacement

provided a sufficient supply of buoyancy

for the additional load due to anticipated

further modifications, without increasing

the draft and the associated partial deterioration of the effectiveness of the main

armor plating. She received six new Bureau Express boilers instead of the original twelve, as well as four Westinghouse coupled turbines and new three blade

3.835m diameter propellers. Despite the

modest increase in power to 35,081 shp,

maximum speed dropped to 20.7 knots

(24 mph, 38,3 km/h), reached during sea

trials after modifications in June 1931.

There was a significant increase in fuel

capacity with tanks newly situated within

the anti-torpedo plating installation. The

standard capacity of 4,630 tons yielded

a range of 13,600 nm (15,650 miles) at

a speed of 15 knots (17.3 mph, 27,8 km/h),

virtually three times better than pre-modernization. The maximum fuel capacity

could be further raised under crisis conditions to 6,180 tons by filling tanks that

were a part of the anti-torpedo defenses

normally filled with air. The armor system was preserved with the exception

of strengthening the main armored deck

adjacent to the top edge of the main plate.

This area received an additional 44.8 mm

(1.7 inches) of plating. This brought the

armor deck to a thickness of 121 mm, but

it should be noted that two plates on top

of each other did not offer the same level

of protection as a single plate of the same

combined thickness. There was a massive

superstructure beginning at the barbette

of Turret No.2 through to the end of the

upper deck installed at the level of the raised front upper deck. With that, the number of decks was increased by one level,

Modernization of both Pennsylvania

Class ships came in 1929, when Congress

approved it with the stipulation that the

upgrades take place at the Norfolk Naval

Yard. Work on the USS Arizona went from

May 4, 1929 to March 3, 1931. The entire

propulsion system was removed, as were

the superstructure, masts and armament,

save for the main guns. The sides of the

hull were upgraded against torpedo

attacks, installed over the existing armor,

equipped with watertight compartments

in part used for fuel storage and partly

used as space for absorbing the energy

of explosions below the waterline. New,

anti-torpedo bulkheads were also set

up. Maximum width of the vessel grew

With President Herbert Hoover on board, returning from a cruise to the West Indies, 29

March 1931. The Vought O3U-1 planes are on

deck, one ready for catapult launching. Note

early type (light weight) aircraft crane. Photographed by a USAAC plane from Langley

Field Virginia (photo: U.S. Naval History and

Heritage Command).

March 2022

INFO Eduard

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