IJN
Kaichu Type submarine
Dimensions
264 | 23 | 13
Tons
1,109 (surfaced)
Armament
4 x forward torpedo tubes
10 Long Lance torpedoes
1 x 80mm gun
2 x 25mm guns
Crew
70 (MIA/KIA)
Sinking History
Completed October 7, 1935 at Kure Navy Yard. The RO-33 is completed, commissioned in the IJN and based in the Maizuru Naval District. Assigned to the Combined Fleet's SubRon 4 in SubDiv 21, commanded by LtCdr Sakamoto Eiichi.
Wartime History
At the start of the Pacific war on December 8, 1941, this sub participated in Operation "E" the Invasion of Malaya. Departs Sasebo with the RO-34 and the Maki Unit to raid enemy communications in the Malaya-Java area.
On February 15, 1942 RO-33, I-53 and I-55 are ordered to intercept HMS Exeter and HMAS Hobart, but are unable to find the ships.
20 February 1942:
Transits the Lombok Strait, Java into the Indian Ocean. From 1 to 4 March 1942: off Tjilatjap, the RO-33 sights several enemy transports and destroyers. LtCdr Sakamoto attempts to attack them, but fails to hit any vessels.
10 March 1942: SubRon 4 is disbanded. The RO-33 and the RO-34 are reassigned to SubRon 6 of Vice Admiral (later Admiral) Inoue Shigeyoshi's (former CO of HIEI) Fourth Fleet, going to Palau and Truk. On April 4, 1942 she was assigned to the South Seas Unit with the RO-34 and departs Truk on April 15, 1942. The RO-33 arrives at Rabaul on 18 April 1942. LtCdr Kuriyama Shigeshi assumes command.
On April 20 1942, RO-33 departs Rabaul to reconnoiter Port Moresby to search the Jomard Passage for convoy routes and to reconnoiter the Russell and Deboyne Islands for suitable anchorages prior to the planned assault on Port Moresby. The RO-33 and RO-34 are later ordered to blockade Port Moresby and guide Japanese shipping into the area. On April 23, 1942 she returns to Rabaul.
On 1 May 1942, departs Rabaul as part of Operation "MO", towards the Jomard Pass in the Louisiade Archipelago with DesRon 6's light cruiser Yubari, four destroyers and a patrol boat escorting a transport Force of 12 transports and a minesweeper.
4 May 1942: The Battle of the Coral Sea:
Rear Admiral (later Admiral) Frank J. Fletcher's Task Force 17 attacks Rear Admiral (later Vice Admiral) Shima Kiyohide's (former CO of OI) Tulagi Invasion Force at Tulagi. Douglas SBD dive-bombers and TBD torpedo-bombers from the YORKTOWN (CV-5) sink a destroyer, three minesweepers and damage four other ships. The next day, Fletcher's force engages Vice Admiral (Admiral, posthumously) Takagi Takeo's (former CO of MUTSU) Carrier Strike Force. SBDs and TBDs from the YORKTOWN and the LEXINGTON (CV-2) sink Rear Admiral (Vice Admiral, posthumously) Goto Aritomo's (former CO of MUTSU) light carrier SHOHO. In turn, Japanese planes damage the oiler USS NEOSHO (AO-23) and sink the destroyer SIMS (DD-409).
5 May 1942:
Arrives off Port Moresby.
8 May 1942:
Aircraft from the LEXINGTON sight the Carrier Strike Force Main Body (SHOKAKU and ZUIKAKU). SBDs from the YORKTOWN and the LEXINGTON damage the SHOKAKU and force her retirement. The ZUIKAKU's air group suffers heavy losses. Takagi's planes damage the YORKTOWN and the LEXINGTON that is further damaged by gasoline explosions. She has to be abandoned and later scuttled by the destroyer PHELPS (DD-360).
10 May 1942:
Departs her patrol area.
19 May 1942:
The Battle of the Coral Sea halts the Japanese thrust toward Port Moresby and they are forced to cancel Operation MO. Returns to Rabaul.
23 May 1942:
Departs Truk with the RO-34.
30 May 1942:
Arrives at Sasebo for overhaul and repair.
9 July 1942:
Departs Sasebo with the RO-34.
17 July 1942:
Arrives at Truk with the RO-34.
23 July 1942:
Departs Truk for Rabaul.
27 July 1942:
Arrives at Rabaul with the RO-34.
29 July 1942:
Departs Rabaul to operate in the Coral Sea in the Port Moresby area and SE coast of New Guinea.
6 August 1942:
North Queensland, Australia. N of Murray Island. The 300-ton M/V MAMUTU set out from Port Moresby for Daru on the western shores of the Gulf of Papua. At 1034 (local), the RO-33 spots the MAMUTU and starts the chase. By 1100, MAMUTU is half-way across the gulf when her crew spots the submarine several miles astern. The RO-33 shells and sinks the MAMUTU at 09-11S, 144-12E. LtCdr Kuriyama orders his machine gunner to open fire on the survivors in the water. Those killed include many women and children. There are only 28 survivors of the 114 persons who were aboard.*
After the American landings on Guadalcanal on August 7, 1942, Vice Admiral Mikawa Gunichi (former CO of KIRISHIMA), CINC, Eighth Fleet, orders SubRon 21's RO-33, then off New Guinea to the Indispensable Strait to reconnoiter the landing area and contact Japanese shore patrols on the island. On August 11, 1942 she arrives off Lunga Point, Guadalcanal. The next day at 1200, the RO-33 arrives off Cape Hunter and contacts the Japanese shore patrol. According to them, an enemy task force consisting of two carriers, two battleships, five cruisers and several transports was spotted leaving Guadalcanal. LtCdr Kuriyama relays this information to his headquarters. The next day, the sub delivers food to Japanese shore patrol at Cape Esperance, then returns to Rabaul on August 16th.
Sinking History
On August 22, 1942 she departs Rabaul to patrol south of Samarai and then proceeds to Port Moresby. On August 26, 1942 LtCdr Kuriyama sends a regular situation report after arriving in his prescribed area. It is the last signal received from the RO-33.
On 29 August 1942 At 1134, the 3,310-ton merchant MALAITA, escorted by Cdr J. C. Morrow's destroyer HMAS ARUNTA, leaves Port Moresby for Cairns, Australia to escape bombing raids. At 1210, near the Port Moresby harbor entrance, the MALAITA is torpedoed by the RO-33 at 09-50S, 144-55E. The torpedo hits the MALAITA below the bridge on her starboard side and she takes on a heavy list to starboard. By 1245, the crew abandons ship fearing that she is about to capsize, but later reboards her. The MALAITA is taken under tow back to Port Moresby.
10 miles SE of Port Moresby. The ARUNTA makes a sonar contact on the RO-33. Cdr Morrow makes four attacks with Mk.VII depth charges and the ARUNTA's crew sees a large oil slick. The RO-33 sinks at 09-36S, 147-06E with all 70 officers and men. On September 1, 1942 the sub is presumed lost off Port Moresby.
References
Wrecks & Reefs page 199 - 207
Tabular Movements
