In 1933, Curacoa became a training ship and in July 1939, two months before the start of the Second World War, she was converted into an anti-aircraft cruiser.

In late 1942, during escort duty, she was accidentally sliced in half and sunk by the ocean liner RMS Queen Mary, with the loss of 337 men.

[5] The main armament of the Ceres-class ships consisted of five BL 6-inch (152 mm) Mk XII guns that were mounted on the centreline and designated '1' to '5' from front to rear.

[1] On commissioning, Curacoa became flagship of the 5th Light Cruiser Squadron, part of the Harwich Force, serving there for the rest of the war.

[10][11] In association with John Cyril Porte's birthday and a medal ceremony at RNAS Felixstowe, her crew was inspected by King George V at Harwich on 26 February.

[1][12] From June onwards, she participated in reconnaissance sweeps ordered by Rear-Admiral Reginald Tyrwhitt, commander of the Harwich Force.

Ten days later, the ship was en route from Helsinki to Liepāja when she struck a mine with her stern, 70 miles (110 km) east of Reval (now Tallinn).

[14] On 4 September 1929, the ship was transferred to the Mediterranean Fleet as the flagship of the 3rd Cruiser Squadron, which was commanded by her first captain, Barry Domvile.

[23] In July 1939, a few months before the outbreak of the Second World War in Europe, she began a conversion into an anti-aircraft cruiser[24] at Chatham Dockyard.

Quadruple Vickers 0.5 in (12.7 mm) AA machinegun mounts replaced the three-inch guns and her torpedo tubes were removed.

Curacoa returned home, but was ordered back to Åndalsnes to protect the beachhead there from German aircraft, arriving on 22 April.

Repeatedly attacked over the next several days, the ship was hit on the forecastle by a 250-kilogram (550 lb) bomb dropped by a bomber from the Third Group of Demonstration Wing 1 (III./Lehrgeschwader 1) on the evening of the 24th.

[29] By September 1942, her anti-aircraft suite had been reinforced by five single mounts for 20-millimetre (0.8 in) Oerlikon light AA guns; a Type 273 long-range surface-search radar was added.

[28] On the morning of 2 October 1942, Curacoa rendezvoused north of Ireland with the ocean liner Queen Mary, which was carrying approximately 10,000 American troops of the 29th Infantry Division.

[31] The elderly cruiser remained on a straight course at a top speed of 25 knots (46 km/h; 29 mph) and would eventually be overtaken by the liner.

"[37] At 14:04, Queen Mary started the starboard turn from a position slightly behind the cruiser and at a distance of two cables (about 400 yards (366 m)).

Boutwood perceived the danger, but the distance was too close for either of the hard turns ordered for each ship to make any difference at the speeds that they were travelling.

[38] Acting under orders not to stop due to the risk of U-boat attacks, Queen Mary steamed onwards with a damaged bow.

[39] Hours later, the convoy's lead escort, consisting of Bramham and HMS Cowdray,[40] returned to rescue approximately 101 survivors, including Boutwood.

[Note 3] Lost with Curacoa were 337 officers and men of her crew, according to the naval casualty file released by The United Kingdom National Archives in June 2013.

Mr. Justice Pilcher exonerated Queen Mary's crew and her owners from blame on 21 January 1947 and laid all fault on Curacoa's officers.