la plata maru
Santos Maru 1925 - 1944
La Plata Maru, 1926 - 1945
Montevideo Maru 1926 - 1942
OSK Lines

During the middle of the 1920's the Osaka Shosen Kaisha ordered three passenger ships for service to South America. The Santos Maru, the La Plata Maru & the Montevideo Maru would in fact provide a westbound round-the-world service, shown in the company's publicity literature of the time as the South American & African joint line.

At this time there was a substantial immigration flow from Japan to Brazil. The Japanese population in Brazil in 1925 was about 50,000 which had increased to 193,000 by 1935, immigrants on this service could expect a forty five day voyage from Kobe to Santos.

From period publicity materials details of the sailings are:

Sailings January - December 1937:
Outward - Kobe, Yokkaichi, Yokohama, Kobe (2nd call), Hong Kong, Singapore, Colombo, Durban, Cape Town, Rio de Janeiro, Santos, Montevideo, Buenos Aires.

Homeward - via Santos, Rio de Janeiro, Belem, Cristobal, Balboa, Los Angeles and Yokohama to Kobe.

Sailings January - December 1938:
Outward - Kobe, Yokkaichi, Yokohama, Kobe (2nd call), Hong Kong, Singapore, Colombo, Durban, Cape Town, Rio de Janeiro, Santos, Montevideo, Buenos Aires.

Optional calls outward - Shimizu, Saigon, Port Elizabeth, East London and Rio Grande
Homeward - via Santos, Rio de Janeiro, Belem, Cristobal, Balboa, Los Angeles and Yokohama to Kobe.

Optional calls homeward - Montevideo, Rosario, Santa Fe, La Plata, Rio Grande, Victoria, Angra dos Reis, Bahia, Maceio, Pernambuco, Fortaleza, Belem, Curaçao and Havana.

For the peace time working of these vessels their sailings were routine, it is the approach of World War II that saw the duties of these ships vary considerably.

La Plata Maru

Since the outbreak of World War II the British Admiralty had been concerned about the passage of Germany men of military age on Japanese ships. This had led to the Asama Maru incident and during January 1940 the Admiralty were planning to intercept the La Plata Maru with similar intent. Fortunately diplomatic means between the United Kingdom & Japan led to the request that the NYK & OSK lines would no longer carry any male passengers of German military age.

In 1941 the ship was renamed the Kanju Maru (or Kanzyu Maru), presumably to disconnect the ship from its original non-Japanese name.

Utilizing Task Force 38 'Operation Gratitude' was launched by Allied forces against the Japanese in South East French Indochina. Amongst many other things this led to the sinking of the Kanju Maru in the Saigon River near Saigon on January 12th 1945. Even in this derelict state the partially sunken ship would continue to draw Allied fire including an attack from a B25J on April 28th 1945.

Santos Maru

Laid down January 1925, launched September 1925, completed December 1925

Home port was Kobe, Japan.

Santos Maru was built for the Osaka Shosen Kaisha by the Mitsubishi Dockyard of Yokahama, the first passenger motor vessel built in Japan. Her passenger accommodations handled 38 first class, 102 third class and 588 emigrants. In November 1925, Santos Maru entered service on OSK's westbound round-the-world service to South Asia, South Africa, the east coast of South America and the Gulf and Pacific coasts of the United States.

On June 11th 1932 the Santos Maru arrived at New Orleans with an alien passenger on board, en route from Brazil to Japan using a through ticket. Not being entitled to enter the United States the immigration officers at New Orleans issued a written order for the steamship to keep the the alien on board at all ports of the United States. On arrival at Galveston, Texas this passenger escaped and entered the United States contrary to the immigration order. This loss was reported to the authorities but the ship sailed prior to the capture of the alien, who was later deported on another vessel of the OSK line. Criminal prosecution of the matter was deemed impractical, so a libel suite was filed in the appropriate federal district court with a $1,000 penalty to enforce the lien against the Santos Maru.

A few days before the beginning of World War II the Santos Maru was the victim of stolen identity by the Windhuk, an armed German passenger liner. The Windhuk was a German vessel 'trapped' in Cape Town and trying to seek passage back to Germany. The first leg of her northbound voyage would take her to Lobito, Angola, from here Buenos Aires was the preferred destination, but this was not possible due to the actions of the pocket battleship Graf Spee. Instead after two months at sea the Windhuk sailed for Santos, Brazil. To enter the port on December 7th 1939 the crew had renamed the vessel the Santos Maru and flew a hand-crafted Japanese flag. Once dockside the German flag was raised and the borrowed name painted out.

In 1941 the Santos Maru was one of five merchant ships requisitioned from her owners and converted by the Imperial Japanese Navy into a submarine tender, taking up this new role sometime in 1942.

Late in February 1942 the Santo Maru sailed to Staring Bay, Kendari, Celebes. to salvage submarine I-5 from a reef, and then carry out repairs on the I-5.

During May 1942 one 150-mm (5.9-inch) gun was fitted in the bow and 4 Type 96 25-mm anti-aircraft guns, two 13.2-mm machine guns and a depth charge thrower were also installed at Yokosuka.

In March 1943 the ship was renamed the Manju Maru (or Manzyu Maru) and reclassified as a Miscellaneous Auxiliary in the Yokosuka Naval District.

August 1943 was spent in convoy 6053 between Kwajalein & Truk. Following this it was part of Convoy 4821 which departed Truk for Yokosuka. On August 22nd 1943 this convoy came under attack from the USS Tullibee SS-284, which torpedoed and sunk one ship.

In the middle of October 1943 the Manju Maru sailed from Singapore in a very small convoy headed for Surabaya.

On March 20th 1944 the Manju Maru sailed from Tateyama in Marianas troop reinforcement convoy Higashi-Matsu ("East Pine") No. 3 Special ("Toku").

The Manju Maru sailed on May 14th 1944 from Tateyama for Saipan in troop convoy Higashi Matsu No. 8. Bad weather was encountered on this trip and two days were spent at Saipan before sailing home to Japan, reaching here on May 26th 1944.

June 20th 1944 found the Manju Maru sailing from Moji with troop convoy HI-67 for Singapore. The convoy came under attack on June 29th 1944 from the USS Bang SS-385. Several ships are hit but they are able to reach Manila. The Manju Maru and its convoy reach Singapore on July 9th 1944. The Manju Maru returns north for Moji on August 4th 1944 as part of convoy HI-70 with a load of bauxite and 130 passengers. Moji is reached on August 15th 1944.

Convoy HI-77 sailed on October 1st 1944 from Moji for Manila & Singapore including the Manju Maru. This convoy came under several submarine attacks after departing Arikawa Bay. On October 6th 1944 the USS Whale SS-239 sank the 10,000 ton oil tanker Akane Maru with the loss of 765 passengers and crew. Later the same day the USS Seahorse SS-304 ssank the frigate CD-21. The next day the USS Baya SS-318, the USS Becuna and the USS Hawkbill SS-366 attacked the convoy west of Manila. One ship was quickly sunk, but the Manju Maru intervened and dropped depth charges to prevent further attacks. The convoy finally reached Singapore on October 12th 1944.

On November 12th 1944 the Manju Maru left Takao for Manila in convoy TAMA 31B. The convoy anchored off the west coast of Formosa on November 15th 1944 to avoid Allied air attacks. On November 19th 1944 the convoy underwent further air attacks and sustained only minimal damage. Manila was finally reached on the afternoon of November 21st 1944.

At midday on November 23rd 1944 convoy MATA-34 left Manila for Takao with just the Manju Maru carrying about 1,300 troops and escorted by two patrol boats and a submarine chaser. The next day this small convoy was sighted by the USS Atule SS-403 passing through the Luzon Strait, 100 miles north of Cape Engano. The submarine launched a torpedo attack shortly after midnight (25th). Patrol boat No. 38 was destroyed whilst the Manju Maru received a hit in Hold No. 5, stopping the ship. The two remaining escorts forced the Atule to withdraw. The Manju Maru finally sank shortly after 5am at 20-14N, 121-40 E. Twenty-four of her crew and about seven hundred troops were lost.

Montevideo Maru

In the middle of January 1941 the Montevideo Maru sailed into Rio De Janeiro with five representatives of the Japanese Ministry for Commerce and Industry onboard. They were to investigate the possibilities of bartering Japanese manufactures and machinery for cereals, cotton, and minerals from Brazil, Paraguay, Uruguay, Argentina and Venezuela.

The events that overtook the Montevideo Maru in the last week of June and the first day of July 1942 are grim reading, coming from a time when the world was at war and the fortunes still favoured the Axis powers. The sinking of the Montevideo Maru would be for Australia its worst maritime disaster with regard to the loss of Australian lives.

The Montevideo Maru had departed Surabaya on May 28th 1942, arriving at Rabaul on June 9th 1942 where its passengers disembarked. Rabaul was the focus of many air raids at the time that the Montevideo Maru was docked at Rabaul, however no damage was sustained by the ship whilst it sat dockside for thirteen days.

The Japanese occupation of Rabaul, New Britain had seen almost all of its captured Australian troops and other civilians placed in a prison camp. On June 22nd 1942 the vast majority of these men (845 troops & 208 civilians) were taken down to the dockside and loaded on to the Montevideo Maru. On July 1st 1942 whilst in transit to Hainan island the ship was intercepted and sunk by the submarine USS Sturgeon. Left behind in Rabaul were the officers and nurses from the mission, they would be shipped out of Rabaul in the first week of July.

On June 30th 1942 the USS Sturgeon had been patrolling northwest of Bojeador, remaining submerged during daylight hours. Surfacing at dusk the submarine sighted a darkened ship shortly after 10pm. The ship was zig-zagging in a westerly direction and making about seventeen knots, a speed which the USS Sturgeon could not achieve despite her best efforts. At this speed and already at a range of about twenty miles the Montevideo Maru would have eventually eluded the USS Sturgeon but the ship slowed down to about twelve knots, reportedly to connect with two destroyers that would provide escort to Hainan. It took about two hours for the USS Sturgeon to catch up with the ship, closing to about 4,000 yards. At 02.25am on July 1st 1942 the USS Sturgeon fired four torpedoes. Four minutes later explosions were heard situated behind the funnel. Ten minutes later the ship was observed sinking stern first.

The Japanese Navy Department reported the loss of the Montevideo Maru to its owners on July 20th 1942. And in a letter dated September 6th 1943 the Japanese Navy notified the Japanese Prisoner of War Information Bureau of the details of the sinking and that 1,053 persons were listed as on the Montevideo Maru when sunk. A list of the names was provided, written in Japanese characters, but with the names only spelled out phonetically. Over time seven formal enquiries were made by the Swiss Legation on behalf of the Australian Government with regard to prisoners of war from the Rabaul area. The only definite reply provided by the Japanese was ‘ it seems that none of the persons referred to are in the hands of Japan and it is believed that all may have taken refuge in the hills'.

The loss of the ship at night, allegedly with no survivors from the Australian troops or civilians onboard and the ongoing Japanese conquest of Rabaul and surrounding lands would at the time create a complete lack of information for the Allies about the significance of the sinking and with the general disarray in the whole region as the Japanese advanced the priorities of the Allies was focused elsewhere.

When the war in the Pacific ended in August 1945 and with many Australian military personnel and civilians still unaccounted for in South East Asia resources were now being made available to determine their fate. With regard to the Montevideo Maru, Major H. S. Williams, of the Australian Army Directorate of Prisoners of War and Internees had been despatched to Japan in search of any information. As a businessman who had spent time in pre-war Japan Major Williams spoke Japanese and was very familiar with its culture. As mentioned above the records were housed at the Japanese Prisoner of War Information Bureau in a small village outside Tokyo. Although initially the Japanese claimed no knowledge of the documents requested, the Major persisted in his search and in late September 1945 eventually uncovered the Japanese Navy communications.

By the first week of October 1945 the fate of the Montevideo Maru and its use as a prisoner of war transport was well documented to the Australian investigating authorities, but because the number of people still missing in that area exceeded the known number of people on the ship (by at least 316), the investigations continued with great intensity. These known facts were stated by the Minister for Transport (Mr. E J Ward) in the Australian House of Representatives on October 5th 1945. The previously mentioned list of names compiled by the Japanese Navy presented challenges in translating because of the names being spelled phonetically. Thus its translation into English and the positive identification of each name with official lists of Australian personnel was fraught with difficulty, and would take time to complete. At this point in time about 250 names had been received from Tokyo, with the notification of next of kin taking place. Since the Montevideo Maru had been loaded quickly it was presumed the list of names had been compiled earlier whilst everyone was detained at the prison camp.

Amongst the civilians lost were many officers of the New Guinea Administration, many of whom were key officials and their replacement would complicate the task of restoring the region's civil administration. Also known to be lost were at least sixteen missionaries from the Methodist, Catholic and Seventh Day Adventist churches. In a document uncovered by Major Williams he states 'Someone at the Bureau (Japanese) had ascertained that some of the missionaries had been lost on the Montevideo Maru. Was this the basis for the Japanese in Rabaul telling Bishop Scharmach about the Montevideo Maru?' This of course was a statement in contrast to an earlier one suggesting the missing men had 'taken to the hills'.

On November 23rd 1945 it was officially announced by the Minister for External Territories, Mr. Ward that the deaths of over six hundred men of the 2/22 Australian Infantry Battalion, other troops and civilian internees had been definitely established. It was stated there is no doubt now they lost their lives when the Montevideo Maru was torpedoed off Luzon on July 1st 1942. Major H S Williams, of the Australian Army Directorate of POW's had possession of the Japanese report and a nominal roll of those who lost their lives. The Montevideo Maru left Rabaul with 1,053 civilian internees and Australian POW aboard. It sank within a few minutes when hit by two torpedoes 60 miles northwest of Luzon. There is little doubt the Japanese battened them down in the holds with no chance of escaping. Only twenty Japanese of a crew of 132 and 88 naval ratings survived.

In the first week of January 1946 it was announced that files relating to the fate of tens of thousands of Allied war prisoners were burned by the Japanese authorities as soon as surrender was announced. This was revealed by Major H. S. Williams, who had just returned from Tokyo. He said that he had obtained the information from a Japanese officer whom he interrogated. The order to burn the documents was given by the Army Department on the day of the surrender. Major Williams was told that the fire in whlch the documents were consumed, burned for four days and destroyed the individual records of thousands of Allied P.O.W.'s who were executed or died in captivity.

Without a doubt the Montevideo Maru was sunk as reported by the Japanese and United States authorities on the early morning of July 1st 1942. However much speculation exists with regard to the fate of the Australian troops and civilians from the Rabaul area that were reported as boarding the vessel on June 22nd 1942.

In the resources section (below) can be found a couple of links that further explore the questions raised by the sinking.

Basic Details

Built: Mitsubishi Zosen KK, Nagasaki
Launched: 1925 (Santos Maru) 1926 (La Plata Maru & Montevideo Maru)
Tonnage: 7,267 tons
Length: 430 feet
Breadth: 56 feet
Draught: 36 ft
Propulsion: Two Sulzer 6ST60 engines totalling 4,600hp at 112 rpm
Auxiliary engines: Three x 4RH31 and one 2RH24 totalling 810hp.
Screws: Two
Speed: 14.5 knots

The engines for the Santos Maru & La Plata Maru were built at Winterthur, the engines for the Montevideo Maru were built by Mitsubishi, Nagasaki.

National Library of Australia : Trove website of archived Australian Newspapers (
Anne McCosker compilation/research:
Rod Miller compilation/research:

Page added August 24th 2007
Last updated July 6th 2011

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