USS Indianapolis (CA-35)

Introduction and Pre-War

USS Indianapolis (CA-35) was a Portland class cruiser that fought in the Aleutians, the Gilbert and Marshall Islands, Saipan, the battle of the Philippine Sea, Tinian, Guam the Carolines, Iwo Jima and Okinawa, but is best know for being sunk after parts of the first Atomic bomb to Tinian. The Indianapolis earned 10 battle stars for World War II service.

The Indianapolis was laid down in March 1930, launched in November 1931 and commissioned on 15 November 1932. She was equipped to serve as a flagship, and that also made her a suitable ship to carry VIPs. One of her first missions after her shakedown cruise was to carry President Roosevelt to Annapolis in July 1933. In September 1933 she became the flagship of the Secretary of the Navy while he conducted an inspection tour of US naval assets in the Pacific. On 1 November 1933 she became flagship of the Scouting Force. In this role she carried President Roosevelt as he reviewed the fleet in 1934 and again as he made a visit to South America, visiting Rio de Janeiro, Buenos Aires and Montevideo.

Wartime Service

When the Japanese attacked Pearl Harbor the Indianapolis was at sea, carrying out a simulated bombardment of Johnston Island (750 nautical miles to the south-west of Hawaii). After the Japanese attack she joined Task Force 12, which took part in an unsuccessful attempt to find the Japanese carriers. She then returned to Pearl Harbor, arriving on 13 December, where she joined Task Force 11.

USS Indianapolis (CA-35), Mare Island, 12 July 1945
USS Indianapolis (CA-35),
Mare Island, 12 July 1945

The Indianapolis provided part of the covering force for the carriers Lexington and Saratoga during early operations in the South Pacific and around New Guinea. Her first combat experience came on 20 February 1942 when the fleet was attacked by eighteen Japanese aircraft, shooting down 16 of them. On 10 March the carriers, with Yorktown added to the force, launched an attack on Japanese shipping at Lae and Salamaua. The fleet was situated south of New Guinea and the aircraft flew north across the island to catch the Japanese by surprise.

After this attack the Indianapolis returned to the United States for a refit at the Mare Island Navy Yard. This lasted until July, when she returned to the Pacific escorting a convoy to Australia. She then moved to the opposite end of the Pacific to take part in the Aleutian Campaign. On 7 August the Indianapolis took part in a bombardment of Kiska Island. In January 1943 she supported the invasion of Amchitka. On 19 February 1943, while steaming southwest of Attu, she intercepted and destroyed the Akagane Maru, a Japanese cargo ship.

The Indianapolis remained in the Aleutians until the end of the campaign. She supported the invasion of Attu in May 1943 and the invasion of Kiska of 15 August. When the Americans landed on Kiska they discovered that the Japanese had evacuated the island under the cover of the terrible weather.

The Indianapolis now returned to the centre of the fighting, become Vice Admiral Spruance's flagship (5th Fleet). She took part in Operation Galvanic, the invasion of the Gilbert Islands, bombarding Tarawa on 19 November and Makin on 20 November. She then supported the US troops fighting on Tarawa.

The Indianapolis was still the fleet flagship for the invasion of the Marshall Islands. She bombarded Kwajalein Atoll on 31 January and supported the invasion of 1 February 1944. On 2 February she even performed a creeping barrage to support the American troops. She was able to enter the lagoon on 4 February, where she remained until the end of the battle.

In March-April 1944 she took part in a series of attacks on the Palau Islands. These were mainly carrier attacks, and aircraft hit the Palau Islands on 30-31 March, Yap and Ulithi on 31 March and Woleai on 1 April. The Indianapolis's main role was to fight off Japanese aircraft and she shot down one torpedo bomber during the raids.

USS Indianapolis (CA-35) at New York, 1934
USS Indianapolis (CA-35) at New York, 1934

In June the Indianapolis took part in the invasion of the Mariana Islands. On 13 June she took part in a bombardment of Saipan, firing her main guns in action. The Japanese responded to the invasion of Saipan by sending a powerful fleet to attack the Americans, hoping to fight the single decisive battle they had built their strategy around. The result was indeed a major battle - the Battle of the Philippine Sea (June 1944), but it would be the Japanese who suffered the defeat. The Indianapolis was part of the escort for a fast carrier force that was sent to raid air bases in Iwo Jima and Chichi Jima then rejoin the fleet just before the main battle. During the battle she shot down one Japanese torpedo aircraft. 

The Indianapolis returned to the Mariana Islands on 23 June. She took part in the fighting on Tinian, before becoming the first US warship to enter Apra Harbor on Guam, a pre-war US base. She then moved to Peleliu, where she bombarded shore targets from 19-29 September.

After serving at Peleliu she returned to Mare Island for a refit. She then joined Admiral Marc Matcher's fast carrier force and was with it for the first carrier attack on Tokyo since the Doolittle raid of April 1942. The attack, on 16-17 February 1945, served both as a blow against Japanese morale, and as cover for the invasion of Iwo Jima.

After the attack on the Home Islands the fleet moved to join the attack on Iwo Jima. The Indianapolis acted as a shore bombardment ship for much of the battle, staying until the start of March.

USS Indianapolis (CA-35) at Pearl Harbor
USS Indianapolis (CA-35)
at Pearl Harbor

The same pattern was repeated for the invasion of Okinawa. In mid-March the fast carriers left Ulithi and on 18 March attacked targets on Kyushu and Honshu. On 24 March the Indianapolis began seven days of shore bombardment at Okinawa. On 31 March she was attacked by a single fighter aircraft. Despite heavy fire the fighter managed to drop a bomb on the port side of the aft main deck, before crashing into the ship. The kamikaze attack did little damage but the bomb penetrated the deck armour, went straight through the entire ship and exploded under her. The explosion created two underwater holes and killed nice. Part of the ship flooded, but the problem was kept under control and she was able to move to a salvage ship under her own power. She had suffered quite severe damage in the attack, but was still just about to make her way back to Mare Island under her own power.

After the last set of repairs was completed the Indianapolis was given an important mission, to carry the parts of the atomic bombs across the Pacific to Tinian. She left San Francisco on 16 July, reached Pearl Harbor on 19 July and got to Tinian on 26 July, a trip of 5,000 miles in 10 days.

The Indianapolis reached Tinian on 26 July and delivered her deadly cargo. Her next port of call was Guam. She was then sent on a routine trip to Leyte, well away from the main combat zones. Her captain, Charles McVay, wanted a destroyer escort but the area was felt to be safe and so she cruiser sailed unescorted. Early in the morning of 30 July 1945 she crossed the path of the Japanese submarine I-58, commanded by Lt. Cdr. Mochitsura Hashimoto. He first six torpedoes, two of which hit the Indianapolis on the starboard front side. She sank in only twelve minutes.

Tragically the loss of the Indianapolis wasn't noticed at Leyte, where she was meant to have arrived on 31 July. Her survivors were finally discovered by a patrolling Lockheed PV-Ventura and the rescue effort finally began. The delay meant that only 316 of the estimated 800 survivors were rescued. The Indianapolis was the last major Allied warship to be sunk during the Second World War.

Wartime Modifications

Early in 1942 the Indianapolis was given quad 1.1in guns to improve her anti-aircraft firepower.

In 1943 the Indianapolis was give fire control and search radar. Some of the radar equipment was carried on a new lattice tripod mast that was added close to the aft funnel. A number of 20mm anti-aircraft guns were also installed. By the time she fought in the Aleutians she also carried a twin 40mm Bofors gun mount on Number Three turret.

By the summer of 1944 six quadruple 40mm Bofors guns had been added and the number of 20mm guns had been increased to nineteen. At the same time the number of aircraft was reduced to three and the starboard catapult removed.

Displacement (standard)


Displacement (loaded)


Top Speed



10,000nm at 15kts

Armour – belt


 - machinery

0.75in belt
2.5in deck

 - magazines

5.75in belt
2.125in deck

 - barbettes


 - gunhouses

2.5in face
2in roof
0.75in side and rear


610ft oa


Nine 8in guns (three 3-gun turrets)
Eight 5in/25 guns (eight single positions)
Eight 0.5in guns (eight single positions)
Four aircraft

Crew complement

807 (917 Indianapolis)

Laid down

31 March 1930


7 November 1931


15 November 1932


30 July 1945

US Heavy Cruisers 1941-45: Pre War Classes, Mark Stille. Looks at the 'treaty cruisers' built in the US between the wars, limited by treaty to 10,000 tons and 8in guns. Five classes of treaty cruisers were produced and they played a major role in the fighting during the Second World War, despite the limits imposed on them by the treaty restrictions. [read full review]
cover cover cover

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How to cite this article: Rickard, J (11 November 2014), USS Indianapolis (CA-35) ,

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