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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