The anti-aircraft cruiser – the US ‘Juneau’ class

by Chris Chant on 14/04/2015

The three ‘Juneau’ class light cruisers of the US Navy were built to a modified ‘Oakland’ class design: the ‘Oakland’ class was a four-ship subset of the ‘Atlanta’ class standard. The design of the ‘Juneau’ class reflected the operating service’s experience in the later part of World War II against Japanese attacks by massed aircraft forces including kamikaze machines. The ships had the same dual-purpose main armament of 12 5-in (127-mm) L/38 guns as the ‘Oakland’ class but with a much enhanced secondary dedicated anti-aircraft battery, but the earlier classes’ depth-charge tracks and torpedo tubes were removed as unnecessary under current conditions. This reduced topweight and, together with a redesigned superstructure which also improved the guns arcs of fire, reduced weight and increased stability, which in the two earlier classes had been the subject of considerable criticism.

Operational experience in World War II  soon after the first ships had been commissioned dictated the addition of more guns and larger numbers of men to operate these as well as to improve the manning of other systems, and the loss of Atlanta (CL-51) and original Juneau (CL-52) on 13 November 1942 in the Naval Battle of Guadalcanal revealed weaknesses in the design’s stability and hull integrity. These and other matters were already under investigation, and the Bureau of Ships’ redesign, at much the same time as the modified ‘Cleveland’ and ‘Fargo’ class light cruisers. The redesign had the same main armament as the ‘Oakland’ class ships, which omitted the two twin 5-in (127-mm) wing mountings of the ‘Atlanta’ class in order to reduce topweight while also providing additional deck area for 40-mm and 20-mm light anti-aircraft weapons, but the bridge and superstructure were redesigned with the dual objects of trimming weight and improved fields of vision. Advantage was taken of these topweight reductions and usable deck area additions to add more light anti-aircraft weapons without adverse effects on stability. Other changes were the lowering of the nos 2 and 5 main armament mounts to main deck level and of the nos 3 and 4 mounts to o1 deck level, the omission of the boat crane, the improvement of watertight integrity by removing doors on the lowest decks between bulkheads.

Centreline main armament

The main battery of the ‘Juneau’ class cruisers comprised 12 5-in (127-mm) L/38 dual-purpose guns in six twin mounts disposed in equal numbers fore and aft of the superstructure on the centreline: these guns were well suited to the medium-range anti-aircraft role, but the battery suffered criticism for its lack of anti-ship ‘punch’ by comparison with contemporary light cruisers such as the ‘Cleveland’ class vessels with a main battery of 12 6-in (152.4-mm) L/47 guns in four triple mounts mm. The ‘Juneau’ class was designed with a secondary anti-aircraft armament of 32 Bofors 40-mm anti-aircraft guns in six quadruple and four twin mounts, and 16 20-mm rapid-fire cannon in eight twin mounts. After World War II, it was planned that the ships be upgraded with a secondary battery of 3-in (76.2-mm) L.50 guns in place of the 40-mm weapons, but only Juneau was converted to this standard.

Sensors associated with the weapons included air-search and fire-control radars, as well as two high-angle/low-angle director control towers for the main armament and 10 radar-equipped local directors for the 40-mm cannon.

Reliable and powerful propulsion

The ‘Juneau’ class ships had the same propulsion arrangement as the ‘Atlanta’ class ships, with four 665-psi Babcock & Wilcox boilers supplying steam to two sets of Westinghouse geared turbines delivering 55920 kW) two two shafts, and with this the ships could maintain 33.6 kt.

The ‘Juneau’ class ships had the same protective armour as the ‘Atlanta’ class ships, and this included a 3.75-in (95-mm) main belt, 3.5-in (89-mm) bulkheads, 2-in (51-mm) main deck amidships and lower deck ends, 1- to 1.5-in (25- to 38-mm) turrets and bridge, 1.5-in (38-mm) barbettes, and 3.75-in (95-mm) conning tower.

The class was designed for a complement of 47 officers and 695 men, but the wartime complement was in the order of 820 men.

The other data for the ‘Juneau’ class cruiser included a displacement of 6,000 tons standard and 8,200 full load, length of 541 ft 6 in (165.05 m) overall, beam of 53 ft 3 in (16.23 m), full-load draught of 26 ft 6 in (8.08 m), and up to 1,450 tons (1473 tonnes) of oil for a range of 7,410 miles (11925 km) at 20 kt.

All three ships were built by Federal Shipbuilding at Kearny, and none was completed in time for service in World War II. The lead ship was Juneau (CL-119), which was named after her lost half-sister (CL-52), laid down on 15 September 1944, launched on 15 July 1945 and commissioned on 15 February 1946. Spokane (CL-120) was laid down on 15 November 1944, launched on 22 September 1945 and commissioned on 17 May 1946. Fresno (CL-121) was laid down on 12 February 1945, launched on 5 March 1946 and commissioned on 27 November 1946.

Spokane and Fresno were decommissioned in 1949 and 1950 before the start of the Korean War (1950/53), but Juneau, by this time redesignated as an anti-aircraft light cruiser (CLAA-119), participated in the conflict. On 2 July 1950, Juneau, the British light cruiser Jamaica and the British sloop Black Swan were attacked by a North Korean force of four motor torpedo boats and two motor gunboats, but the firepower of the three allied warships sank three of the torpedo boats and both gunboats near Chumonchin Chan. Juneau was decommissioned in 1955. All three of the ‘Juneau’ class ships were considered for refitting as guided missile cruisers or anti-submarine warfare ships, but were sold for scrap in between 1961 and 1966.

{ 1 comment… read it below or add one }

K. Jacobs February 6, 2018 at 6:34 pm

You are best known as a British aviation and vehicle writer, not a naval writer.

All the more reason you should put Sources for your writings, and not plagiarize other peoples works, especially as a non-naval writer.

You owe you followers at least that.

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