NAVYPEDIA

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  Concord 1935

Ships

No	Name	Yard No	Builder	Laid down	Launched	Comm	Fate
CL4	Omaha	30	Todd, Tacoma	6.12.1918	14.12.1920	24.2.1923	stricken 11.1945
CL5	Milwaukee	31	Todd, Tacoma	13.12.1918	24.3.1921	20.6.1923	to Soviet Union 4.1944-3/1949 (Мурманск [Murmansk]), stricken 3.1949
CL6	Cincinnati	32	Todd, Tacoma	15.5.1920	23.5.1921	1.1.1924	stricken 11.1945
CL7	Raleigh	1382	Bethlehem, Quincy	16.8.1920	25.10.1922	6.2.1924	stricken 11.1945
CL8	Detroit	1383	Bethlehem, Quincy	10.11.1920	29.6.1922	31.7.1923	stricken 1.1946
CL9	Richmond	448	Cramp, Philadelphia	16.2.1920	29.9.1921	2.7.1923	stricken 1.1946
CL10	Concord	449	Cramp, Philadelphia	29.3.1920	15.12.1921	3.11.1923	stricken 12.1945
CL11	Trenton	501	Cramp, Philadelphia	18.8.1920	16.4.1923	19.4.1924	stricken 1.1946
CL12	Marblehead	502	Cramp, Philadelphia	4.8.1920	9.10.1923	8.9.1924	stricken 11.1945
CL13	Memphis	503	Cramp, Philadelphia	14.10.1920	17.4.1924	4.2.1925	stricken 1.1946

Technical data

Displacement normal, t	7050
Displacement full, t	9508
Length, m	167.6 wl 169.4 oa
Breadth, m	16.9
Draught, m	4.11
No of shafts	4
Machinery	4 sets Westinghouse geared steam turbines, 12 Yarrow boilers
Power, h. p.	90000
Max speed, kts	34
Fuel, t	oil 1852
Endurance, nm(kts)	8460(10)
Armour, mm	belt: 76, deck: 38, CT: 32
Armament	2 x 2 - 152/53 Mk 12.14/18, 8 x 1 - 152/53 Mk 12.14/18, 4 x 1 - 76/50 Mk 10.18, 2 x 3 - 533 TT, 2 x 2 - 533 TT, 2 catapults, 2 seaplanes (VE-9, UO, MO)
Complement	458

Standard scale images

Graphics

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.