The Pacific War Online Encyclopedia
|Previous: Olongapo||Table of Contents||Next: Ombilin|
|Tonnage||7100 tons standard displacement
|Dimensions||555'6" by 55'5" by 15'1"
169.32m by 16.89m by 4.60m
|Maximum speed||35 knots|
|Armament||2x2, 8x1 6"/53
4x1 3"/50 AA guns
|Protection||About 570 tons:
3" (76mm) machinery belt
3" (76mm) aft bulkhead
1.5" (38mm) forward bulkhead
1.5 " (38mm) armor deck
||4-shaft geared turbine
|Bunkerage||1852 tons fuel oil|
|Range||6400 nautical miles (11,900 km) at 10 knots|
1941: By start of hostilies, Marblehead,
Raleigh, Detroit, and Richmond had
landed the lower aft pair of casemated 6" guns.
1942: Light antiaircraft of 2x4 1.1"/75 AA guns, 8x1 20mm Oerlikon AA guns. SC and FC radar added.
1943-1944: 1.1" guns replaced by 2x4 40mm Bofors
AA guns and
the 20mm were increased to 12. Two 6" removed and another
with a quad 40mm gun. Radar upgraded to 2 SG
and a second FC set.
The Omahas were completed in 1923-1925. The first cruisers built by the United States since 1905, they reflected a long design process marked by strong disagreement about what kind of cruisers were needed. Discussion ranged from scout cruisers to battle cruisers, but the final design was a small scout cruiser, sometimes described as a super destroyer, which was to have very high speed, extensive aircraft facilities, torpedo armament, and minelaying capability. Equipment for scouting included a tall mast for lookout stations, an oversized rangefinder and telescope, and very powerful radio facilities (for the time).
The ships looked great on paper but were terrible
practice, largely because too much was attempted on the design
displacement, which resulted in excessive weight-saving measures.
hulls leaked, they were top-heavy, their armament was inadequate,
flimsy. The guns were arranged to maximize forward and aft
firepower, but this came at the expense of the broadside firing
Habitability was minimal and most facilities were only up to
destroyer standards. Minelaying capability was apparently
abandoned during construction and
the conning tower and torpedo tubes were removed before war broke
The Omahas were so bad
the U.S. Navy was willing to
turn over the Milwaukee
to the Soviets
One bright point is that the machinery was quite
powerful, yielding a high maximum speed (the fastest of any
cruisers of their day), and machinery dispersal in
alternating fire and engine rooms enhanced survivability and
later U.S. cruiser designs. However, the endurance was much less
than hoped for, particularly bad for the first four ships of the
(of which only Raleigh
ever deployed to the Pacific.)
The ships were never used in their design role as fast
scouts. Instead, they were employed as destroyer flotilla leaders.
The lower pair of casemated guns fore and aft were problematic,
the aft pair in particular being very wet, and the lower aft guns
were eventually removed entirely from about half the units. A 1940
proposal to convert the ships to antiaircraft cruisers
with a substantial 5"/38
armament and improved light antiaircraft was never carried out.
Surprisingly, none were lost in combat, though Marblehead was very badly damaged during the defense of the Malay Barrier.
|Concord||Arrived 1942-2-5 (San Diego)|
The Pacific War Online Encyclopedia © 2007, 2009, 2012-2015 by Kent G. Budge. Index
Comment on this article