La Jolla-class cruiser

## Class overview

25,450 t (full load)

Actual:

21,763 t (standard)

25,463 t (full load)

Actual:

141,247 shp (105,370 kW) (forward)

37,170 shp (27,718 kW) (astern)

8 Babcock & Wilcox boilers

4 sets of General Electric geared turbines

4 x screws

### Range

10,000 nautical miles (18,520 km; 11,508 mi) at 15 knots (27.78 km/h; 17.26 mph)

### Complement

Design:104 officers, 1142 enlisted

1246 crew total

La Jolla, 1945:

134 officers, over 1800 enlisted

### Armament

As completed:9 x 12 in (305mm)/50 caliber Mark 8 guns in two 3-gun turrets

16 x 5 in (127mm)/38 caliber Mark 12 guns in eight twin mountings

6 x anti-aircraft tubs for 1.1"(28mm)/75 caliber quad-mount autocannon, US Army 37mm gun M1 autocannon, 40mm/56 caliber Bofors quad-mount autocannon or 3"(76.2mm)/50 caliber Mark 21 single mount AA guns

3 x M2 Browning .50 (12.7mm) machine guns

1945:

Up-to 14 x anti-aircraft tubs

Numerous 20mm Oerlikon autocannon

3 x M2 Browning .50 (12.7mm) machine guns

### Armour

Belt: 6.1 in (155 mm), declined 20 degrees (outwards)

Barbettes:

6.1 in (155 mm) uniform

Turrets:

7.99 in (203 mm) faceplates (main battery)

6.1 in (155 mm) sides and top

1.5 in (38 mm) gunhouse plating (5 in(127mm) battery)

Decks:

1.5 in (38 mm) weather deck

2.99 in (76 mm) main armor deck

2.01 in (51 mm) over ends

Conning tower:

7.99 in (203 mm) uniform

### Aircraft

4 x OS2U Kingfisher or SC SeahawkAmidships below deck hangar

The ***La Jolla*-class cruisers** were a class of six large cruisers of the United States Navy, ordered a short time before World War II commenced. Though named large cruisers, they had characteristics of both heavy cruisers and battlecruisers. Four ships of the original six ship class where completed, and they where named for either cities of insular areas, or cities of state cities or communities. Though they incorporated the new designation of "CB" for large cruiser into their hull codes, the numbers began at *7*, in reference to the Cincinnati-class, the first multi-ship class of cruiser authorized - armored cruiser names, states, would later be used for battleships, and where thus unsuitable for re-use.

This new class of warship for the U.S. Navy was built after observations of German warships built with 11 inch (280 mm) guns - *Deutchland* and *Scharnhorst* - and rumors the Imperial Japanese Navy where building new battlecruisers. Though the Japanese did not actually construct a new battlecruiser style warship, the need for a cruiser type warship with the capability to effectively combat both traditional 8-inch (203 mm) gun heavy cruisers and the perceived post-heavy cruiser large warship emerged.

What resulted for the U.S. Navy was an array of complicated designs, some ranging from a mere 5000 t or 10,000 t increase from a 14,500 t heavy cruiser such as Baltimore, to 30,000 t warships comparable in size and tonnage to the U.S.' own recent *North Carolina*-class battleships. The final 21,750 t design has been criticized as poor in firepower and protection, and being as timely to produce and expensive as then-modern battleships, whilst lacking the mission they where designed for. Ultimately, only four ships where completed, all with light combat history, as they where expensive to operate and unable to be meaningfully refit for the type of missile and jet aircraft combat that emerged with the beginning of the Cold War. The U.S. Navy consolidated efforts in maintaining and upgrading the later *Iowa*-class battleships and save for bombardment missions off Vietnam, the class had no action after the Korean War. Successively decommissioned after each war, and having found quick obsolesce in reserve, only the mothballed hulk of *Charlotte Amalie* survives today.

## Description

### Propulsion

Propulsion design was similar to Essex-class aircraft carrier machinery and consisted of 8 boilers and 4 geared tubines, producing a top speed of 33.1 knots. Per shaft, the reversing turbine was rated for 3.8 times less the power of forward turbine sets. The boilers where arranged---

Late in the design process, the stern and skeg designs of the South Dakota-class battleships was incorporated into the ships, which produced a distinctive channel between the outboard shafts, between which was the center shafts.

The ships carried 2,055 t of heavy fuel oil for propulsion normally, but at maximum could carry 3,700 t in their bunkers, as a result of their need for extended Pacific operations. At 15 knots, the ships where rated for 10,000 nautical miles (18,520 km) of range at a normal displacement and a clean hull.

### Armament

The new 12 in(305mm)/50 caliber Mark 8 gun was selected for it's promising performance and comparatively simpler and lighter design. At some 8000 tons lighter than the Alaska-class designs, only two triple turrets, one at each end, was provided.

The standard 5 in(127mm)/37 caliber Mark 12 guns was used in twin mounts for the secondary battery, with two centerline mounts, and the remainder six mounts placed equally on each side. Such an arrangement provided the ability of five mounts to fire to one side, in line with US battleships, rather than US cruisers who could only manage four twin 5 in mounts per side.

Because of the long construction from 1940 through 1944, the autocannon armament changed from the 1.1 in(28 mm) autocannon to the 40mm Bofors autocannon. Two to three tubs where provided on each side of the superstructure as built, for a total of six multiple mount autocannons for the ship. Due to shortages of armament at the time, La Jolla was completed with an experimental and ad-hoc anti-aircraft battery of 3 in(76.2mm)/50 caliber Mark 21 single shot high-angle artillery in place of the automatic cannon battery. This was not considered a success due to the difficulties of accurately setting time fuses and directing the large 3 inch guns with a basic light anti-aircraft gun director.

### Protection

The original designed presented a similar ship as the ones completed, however with an 7 inch (177.8 mm) armored belt instead of the final design's 6.1 inch (155 mm) belt. The saved weight was invested back into a heavier (by two twin guns) dual-purpose battery and the then-new radar equipment complimented by a rearranged superstructure.

Main battery gunhouses and the conning tower was provided with the thickest - 8 in(203.4 mm) armor on the ship - enough to withstand direct hits from 203 mm artillery as used by Heavy Cruisers of any nation.

There was two armored decks, with the upper being a relatively thin deck placed at the weather deck level, designed to withstand splinters and small ordnance, and a thick main 2.99 in (76 mm) deck designed to stop enemy shells and bombs from entering the armored citadel placed atop the belt.

Torpedo protection comprised of a 2.5 m deep void with a 2.49 in (63.3 mm) thick holding bulkhead inboard of a 0.5 in (12.7 mm) thick division between the holding bulkhead and the ship's skin. This formed a two layer system with oil occupying the distance from the external skin to the middle of the torpedo defense system, and a void for the remaining distance to the holding bulkhead. Due to the system's shallow depth, it would have offered poor protection, comparable to that of existing US heavy cruisers, rather than that of a battleship's, who maybe a torpedo defense system twice as deep and with multiple, alternating liquid and oil tank layers to absorb and isolate blast from torpedoes or mines.

## Ships

### USS *La Jolla (CB-7)*

Completed relatively quickly but suffered numerous technical problems through WWII. Following the Japanese surrender, returned to the US for remedial refits and repairs, after which was then sent for escort and bombardment missions in the Korean war in her largely WWII form. Decommissioned immediately following the Korean War. Name was released prior to Los Angeles-class naming and became a miscellaneous vessel until was sold for scrap and broken up in 1991.

Named for the location of *Camp Matthews* Marine Corps base in La Jolla.

### USS *Charlotte Amalie* *(CB-8)*

Deployed to the Pacific during WW2 with light action, then returned to the US. Light escort and bombardment missions during the Korean and Vietnam Wars. Decommissioned following the Vietnam War, but retained in mothball fleet to the present.

Named for Charlotte Amalie, the capital city of the U.S. Virgin Islands.

### USS *Agana* *(CB-9)*

Deployed to Europe but saw no combat. Repatriated Allied nationals until 1947. Following repatriation duty, kept on US Eastern seaboard until the conclusion of the Korean War, then was decommissioned and later scrapped beginning in 1962. As the latest member of the class available, it had been slated for conversion to a guided missile warship to leverage the existing flagship facilities and large size, but this never materialized for cost and practicality reasons.

Named for Agana (Hagåtña), the capital city of Guam.

### USS *Pueblo* *(CB-10)*

Hastily sent to the Pacific but irreparably damaged by kamikaze attacks at the Battle of Iwo Jima. With the Allied victory soon after, was scrapped in Japan 1951.

Named for Pueblo, Colorado; a major economic and steel producing city within the U.S. at that time.

### USS *Batton Rouge* *(CB-11)*

Construction halted during building. Partially completed hull scrapped 1946.

Named for Baton Rouge, Louisiana; a major center of industry within the U.S..

### USS *Charlotte* *(CB-12)*

Construction halted during building. Partially completed hull scrapped 1946.

Named for Charlotte, North Carolina; the then second largest city in it's state, and a major business center.