home

fighting ships of the world

UNITED STATES NAVY (UNITED STATES OF AMERICA)

CRUISERS

OMAHA light cruisers (1923-1925)

Detroit 1945

Richmond 1945

Project history: Omaha class cruisers were built in limits of the arrogant shipbuilding programme of 1916. One of the main requirements to a 7000t cruiser-scout was 35kt speed. This circumstance has predetermined an appreciable out-of-balance of main project particulars. The hull was as much as possible narrow, having given to clear "destroyer" lines. Thus a construction for weight economy was probably facilitated, that in a combination with very powerful and, as consequence, heavy-weight machinery led to vibration on full speed. The excessive thrust on achievement of high speed has led to displacement, assigned on arms and protection, has appeared notably less, than at foreign contemporaries: so, only 8% of displacement was assigned on protection. Besides, the desire to ensure maximum fire at fore and aft angles has led to introduction of doubtful arrangement of main artillery in two-level casemates fore and aft: they notably made ship ends heavier, thus it is not enough defending guns from fire of the opponent as had only splinterproof protection. According to the design new cruiser should have 7050t displacement, 35kt speed, armament consisted of 10 152mm/53 guns (4 in fore casemates, 4 aft and 2 more guns on open mounts amidships), 2 76mm/50 AA guns and 2 twin 533mm TTs.

Building contract was signed 8.7.1916, however first ships were laid down only two years later after the design was significantly remade (basically because of critical expressions about insufficient armament). 152mm open mounts were refused, but twin turrets were appeared at ship ends (even more having increased a local overload). Torpedo armament was strengthened, having added to two twin TTs on a main deck two more triple on upper (fwd from a stern casemate). Originally planned quarter-deck catapult was refused, being replaced by two trainable on an upper deck. Design changes have led to displacement growth approximately on 400t, that decreasing speed on 1kt. For the first time in USN practice machinery was arranged on en echelon: engine rooms were placed between fore and stern boiler rooms groups. Turbines and boilers were produced by different companies and that has led to appreciable disorder of running characteristics, and the ships have appeared are shared on group with "high endurance" (CL9-13) and group with "low endurance" (CL4-8). However a planed endurance (10000nm at 10kts) was never possible to achieve.

In 1940 it was planed to convert the Omahas to air defence cruisers armed by 2 twin 152/53mm guns, 7 single 127/38mm DP guns and 6 quadruple 28mm MGs, but their stability in this configuration caused concern and modernization was cancelled.

Ship protection: Main 5.8m high belt protected only machinery and was closed by 38mm fore and 76mm aft bulkheads. Main deck consisted of 22mm STS armour and 15mm plating. Guns had only 6mm protection.

Modernizations: 1924 - 1925, all: - 2 x 2 - 533 TT

1925 - 1941, Cincinnati, Raleigh, Detroit, Richmond: - 2 x 1 - 152/53

1925 - 1941, Marblehead: - 1 x1 - 152/53

1941, Omaha, Milwaukee, Detroit, Richmond, Trenton, Marblehead, Memphis: + 4 x 1 - 76/50 Mk 20, 8 x 1 - 12.7/90

1941, Cincinnati, Raleigh, Concord: + 2 x 4 - 28/75 Mk 1

1942, Omaha, Milwaukee, Trenton, Memphis: - 2 x 1 - 152/53, 1 x 1 - 76/50, 8 x 1 - 12.7/90; + 2 x 4 - 28/75 Mk 1, 8 x 1 - 20/70 Mk 4, SC, Mk 3 radars

1942, Cincinnati, Raleigh: - 8 x 1 - 12.7/90; + 3 x 1 - 76/50 Mk 20, 8 x 1 - 20/70 Mk 4, SC, Mk 3 radars

1942, Detroit, Richmond, Marblehead: - 1 x 1 - 76/50, 8 x 1 - 12.7/90; + 2 x 4 - 28/75 Mk 1, 8 x 1 - 20/70 Mk 4, SC, Mk 3 radars

1942, Concord: - 2 x 1 - 152/53, 8 x 1 - 12.7/90; + 3 x 1 - 76/50 Mk 20, 8 x 1 - 20/70 Mk 4, SC, Mk 3 radars

late 1942, Cincinnati, Memphis: - SC radar; + SK radar

1943 - 1944, Omaha, Milwaukee, Detroit, Concord, Trenton, Marblehead: - 1 x 1 - 76/50, 2 x 4 - 28/75, SC radar; + 3 x 2 - 40/56 Mk 1.2, 4 x 1 - 20/70 Mk 4, SK, 2x SG, Mk 3 (2nd) radars

1943 - 1944, Cincinnati: - 2 x 4 - 28/75, 2 x 3 - 533 TT; + 1 x 1 - 76/50 Mk 20, 3 x 2 - 40/56 Mk 1.2, 2 x 1 - 40/56 Mk 1.2, 2x SG, Mk 3 (2nd) radars

1943 - 1944, Raleigh: - 2 x 4 - 28/75, SC radar; + 1 x 1 - 76/50 Mk 20, 2x SG, SK, Mk 3 (2nd) radars

1943 - 1944, Richmond: - 1 x 1 - 76/50, 2 x 4 - 28/75; + 3 x 2 - 40/56 Mk 1.2, 4 x 1 - 20/70 Mk 4, 2x SG, Mk 3 (2nd) radars

1943 - 1944, Memphis: - 2 x 4 - 28/75; + 2 x 2 - 40/56 Mk 1.2, 4 x 1 - 20/70 Mk 4, 2x SG, Mk 3 (2nd) radars

1945, Detroit: - 2 x 1 - 152/53, 2 x 3 - 533 TT; + 2 x 2 - 40/56 Mk 1.2

1/1946, Detroit, Richmond, Trenton: 2 x 2 - 152/53 Mk 16, 6 x 1 - 152/53 Mk 13, 6 x 1 - 76/50 Mk 11.20, 3 x 2 - 40/60 Mk 1, 12 x 1 - 20/70 Mk 10, 2 x 3 - 533 TT, 2 catapults, 2 seaplanes, SK, 2x SG, 2x Mk 3 radars

1/1946, Memphis: 2 x 2 - 152/53 Mk 16, 6 x 1 - 152/53 Mk 13, 7 x 1 - 76/50 Mk 11.20, 2 x 2 - 40/60 Mk 1, 12 x 1 - 20/70 Mk 10, 2 x 3 - 533 TT, 2 catapults, 2 seaplanes, 2x SG, SK, 2x Mk 3 radars

Naval service: Raleigh was badly damaged in Pearl Harbour 7.12.1941 by Japanese air torpedo and was under repair till July, 1942. Marblehead 5.1.1942 received 2 direct bomb hits and some near-misses, and was under repair till the end of 1942.

Concord 1935

© Ivan Gogin, 2014-15