HMS Battler (D18) was an American-built escort carrier that served with the Royal Navy during the Second World War.

She was laid down on 15 April 1941, as a C3-S-A1, the third replacement for the freighter Mormacmail, for Moore-McCormack Lines, Inc., under Maritime Commission contract at Pascagoula, Mississippi, by Ingalls Shipbuilding, MC Hull 160.

She was purchased by the United States Navy on 7 January 1942, for conversion to a Bogue-class escort carrier and renamed Altamaha.

She was renamed HMS Battler (D18) and commissioned into the Royal Navy on 15 November 1942, as an Attacker-class escort carrier.

[4] The ship had complement of 646 men, who lived in crew accommodation that was significantly different from the arrangements that were normal for the Royal Navy at the time.

The separate messes no longer had to prepare their own food, as everything was cooked in the galley and served cafeteria style in a central dining area.

The traditional hammocks were replaced by three-tier bunk-beds, 18 to a cabin, which were hinged and could be tied up to provide extra space when not in use.

Power was provided by two boilers feeding steam to a turbine driving one shaft, giving 8,500 bhp (6,300 kW), which could propel the ship at 18 kn (33 km/h; 21 mph).

[12] The anti-submarine aircraft employed were initially the Fairey Swordfish and later the Grumman Avenger, which could be armed with torpedoes, depth charges, 250 lb (110 kg) bombs or RP-3 rocket projectiles.

Battler arrived in New York City, on 18 December, and proceeded to Todd Erie Basin Dry Docks, Inc. to clean out her fuel tanks.

Battler launched two Seafires at 2230 on 24 June, to deal with a four engined Focke Wulf FW 200 "Condor" which was shadowing the convoy.

Reaching Greenock, on 28 June, Battler had proved herself efficient on her maiden convoy escort venture.

Battler set sail for Gibraltar, and the Mediterranean theatre, on 2 August, along with her sister ships Attacker, Hunter, and Stalker, from Clyde.

On 1 September 1943, Battler became part of "Task Force 88", consisting of the escort carriers Attacker, Hunter, Stalker, the aircraft repair ship Unicorn, the cruisers Euryalus, Scylla, Charybdis, the destroyers Cleveland, Holcombe, Atherstone, Liddesdale, Farndale, Calpe, and the Polish destroyers Ślązak and Krakowiak.

On 20 September, Attacker, Hunter, and Stalker returned to the United Kingdom for refit and replacement aircraft, while Battler proceeded to Gibraltar.

On 22 September 1943, Battler embarked 834 squadron and joined Carlisle, Aldenham, Rockwood, and the Greek destroyers Kanaris, Miaoulis, and Themistoklis escorting Convoy KMF 24 enroute to Port Said.

On 17 October, after having her boilers cleaned at Aden, Battler joined Convoy AB 17, along with Rotherham, Quiberon, and Quality for escort to Bombay.

She arrived on 26 October, and left 4 November, along with Quiberon and Quality to rendezvous with the LST Convoy AB 18A for escort to Bombay.

The purpose of the operation was to search for the blockade runner, U-boat supply ship Charlotte Schliemann, southeast of Mauritius.

She returned to Mauritius, in early March, to search for another blockade runner, the U-boat supply ship Brake, during Operation Covered.

On 12 March, after seven days of searching, a Swordfish of 834 squadron, spotted the tanker Brake with two or three U-boats alongside her, 900 nmi (1,700 km; 1,000 mi) southeast of Mauritius.

Battler launched Swordfish armed with rockets to shadow Brake in an attempt not to alert the tanker to the carriers presence, while Roebuck moved in for an attack.

At noon, Roebuck commenced her attack on Brake forcing her crew to scuttle her, while the Swordfish damaged one of the U-boats.

She disembarked 834 squadron at RNAS Katukurunda on 25 July, where six Wildcat Vs were waiting to replace the Seafires that had been left at Durban.

After returning to Colombo, to prepare for her ferry run to Sydney, she departed on 9 December 1944, with the carrier Atheling, the cruiser Achilles, and the destroyers Wager and Whelp, for Australia.

They were joined on 10 December, by the ships Swiftsure, the flagship of Fourth Cruiser Squadron commander Rear Admiral E.J.P.

Embarking aircraft at Naval Station Norfolk, she sailed for New York on 13 February, to join Convoy CU 59.

On 5 March 1945, Battler was allocated to Western Approaches Command for use as a Deck Landing Training carrier.