TheJapanese raiders in the Indian Ocean were those vessels used by theImperial Japanese Navy (IJN) during theSecond World War to pursue its war onAllied commerce in that theatre. Possessing a powerful fleet of warships, prior to the start of World War II, the IJN had strategically planned to fight a war of fleet actions, and as a consequence delegated few resources to raiding merchant vessels. Nevertheless, in 1940, two passenger-cargo vessels –Aikoku Maru andHōkoku Maru – of the Osaka Shipping Line were requisitioned for conversion toarmed merchant cruisers (AMC)s, in anticipation of the likely thrust southward by the Japanese. These vessels were subsequently used asmerchant raiders attacking Allied commercial shipping along vitalsea lanes of communication between Australia and the Middle East. Using their comprehensive armament and speed to their advantage, the raiders experienced a brief period of success. Japanese raiding in the Indian Ocean largely ceased by the end of 1942 after an action with a Dutch vessel, theOndina and aRoyal Indian Navycorvette,HMIS Bengal in which theHōkoku Maru was sunk.
Nations fightingBritain during bothworld wars in the 20th century devoted substantial effort to the disruption of oceanictrade as a means of weakening theBritish Empire. In late 1942,Axis activities in theIndian Ocean had virtually come to an end.Germanmerchant raiders, originally disrupting theshipping lanes in these waters, had with few exceptions, been destroyed by theRoyal Navy or begun the long journey home.[citation needed]
By virtue of their powerful battle fleets, theImperial Japanese Navy (IJN) had strategically planned to fight a war of fleet actions ("Guerre d'escadre"), and as a consequence delegated few resources to raiding merchant vessels ("Guerre de course"). Nonetheless, other than theirsuccessful sortie to Ceylon in April 1942, the Japanese Navy had decided to keep the pressure on the shipping lanes, primarily due to the Allies' ever-growinglogistical strength in the war. Large and valuabletankers maintained a continuous stream ofoil and other products from theMiddle East toAustralia and surrounding islands. The continuous pleas by the Germans possibly[1] had a large influence on this decision, as the Indian Ocean was the primary area of operations in which the two Axis powers had the most physical coordination with each other, in regards to re-supply and the exchange of military (naval) intelligence.[citation needed]
In 1940, two passenger-cargo vessels of theOsaka Shipping Line were requisitioned for conversion toarmed merchant cruisers (AMC)s, in anticipation of the likely thrust southward by the Japanese. TheHōkoku Maru (thename ship ofthe class) andAikoku Maru, both under construction for the route between theEmpire of Japan and South America, started their rebuilds in 1941, and by the time they were commissioned, the 10,470-ton vessels were heavily armed.[1] The main armament consisted of eight140 mm/50 caliber guns, which were augmented by two 80 mm guns, and four 25 mm guns. There were four 533 mm torpedo tubes in twin mounts, and each vessel had twoMitsubishi F1M2 "Pete" Type 0 observation seaplanes,[2] each armed with two fixed forward firingType 97 machine guns, one flexibly mounted rearward-firingType 92 machine gun and 120 kg of bombs.[3]
With their heavy armament, the two Japanese merchant raiders could overpower any smaller combatant or merchant vessel, and their speed enabled them (in combination with their floatplanes) to search large areas of ocean. In service, they were organized as the 24th Special Cruiser Squadron under Rear-AdmiralMoriharu Takeda.Hōkoku Maru was modified to serve as Admiral Takeda's flagship with space for his staff of four officers and eighteen men.[2]
The 24th Special Cruiser Squadron departedHiroshima Bay on 15 November 1941 under radio silence and blacked out at night to arrive in a standby position atJaluit Atoll in theMarshall Islands. They departed Jaluit on 26 November 1941 to patrol the sea lanes between Australia,Samoa,Fiji, theUnited States, and thePanama Canal. The operational plan was for one ship to lie-to and drift while performing maintenance, as the other ship carried out a perimeter patrol searching for enemy shipping. The two ships would spend the hours of darkness within visual range; the ships then reversed roles the following day. Following theAttack on Pearl Harbor, the search objective changed from avoiding detection to locating enemy commerce.[2]
Following sunset on 12 December 1941,Hōkoku Maru stopped the 6,210-ton United States freighterVincent bound for the Panama Canal fromSydney, Australia at 23 south, 118 west. The old freighter was sunk after taking her crew of 38 aboard the two raiders. The Japanese ships then left the area to avoid any response toVincent's radioSOS.[2]
Routine searching resumed on 23 December 1941. On 31 December, a seaplane fromAikoku Maru found and circled the 3,275-ton United States freighterMalama bound forNew Zealand fromHonolulu with a cargo ofUS Army Air Force trucks and aircraft engines. The seaplane was observed byMalama, but was apparently lost to operational problems before returning toAikoku Maru. The squadron commenced a search for the missing seaplane at 1810 and searched through the moonlit night. Aircraft were launched at 0700 on 1 January 1942 to expand the search. One of the seaplanes foundMalama at 0910, circled at low altitude and ordered the ship to stop with a burst of machine gun fire.Malama began to broadcast distress messages which continued until 1415. Admiral Takeda was 130 miles (210 km) away, but intercepted the distress calls and ordered the plane to return to be rearmed with bombs.Malama was scuttled by her crew at a position 25 south, 155 west when the aircraft returned. The squadron left the area after taking the freighter's crew of 38 aboard as prisoners.[2]
On 8 January 1942, the raiders resumed search operations and between 16 and 20 January the squadron intercepted extremely loud radio signals causing them to believeAllied warships were nearby. They successfully evaded detection by AdmiralWilliam Halsey'sTask Force 8. They replenished atTruk on 4 February 1942 and transferred the prisoners to the Oita Bay Naval Air Command on 13 February.[2]
The squadron then entered theKure Navy Yard where each ship received eight modern 14 cm (5.5-inch) guns to replace the four 15 cm (5.9-inch) guns ofRusso-Japanese War vintage installed the previous autumn. More modern seaplanes were embarked when the squadron deployed to the Indian Ocean with the additional duty of resupplying the Japanesesubmarines operating in theMozambique Channel. Between 5 June and 13 July 1942, the submarines sank 21 ships, for a total of 92,498 tons.[2] TheHōkoku Maru andAikoku Maru added additional ships to that score. With these successes, they had sunk or captured five merchant ships within a year, totalling 31,303 tons. They leftSingapore on 5 November on their fourth sortie, under the overall command of Captain Imazato Hiroshi.[citation needed]
Victims of Japanese raiders included theGenota, aDutch vessel of 7,987 tons, which was captured on 9 May 1942; theElysia, aBritish vessel of 6,757 tons), which was sunk on 5 June 1942; and theHauraki, a New Zealand vessel of 7,112 tons, which was captured on 12 July 1942.[citation needed]
TheOndina was a moderntanker built forLa Corona, one ofShell's shipping companies. She was new, relatively fast and by contemporary standards not lightly armed with a4"/50 caliber gun on her stern and several machine guns for anti-aircraft use. Under Captain W. Horsman, she was deployed betweenFremantle in Australia andAbadan on theoil-rich shores of thePersian Gulf. On her journey to Abadan, she was protected by a singlecorvette,HMIS Bengal under the command of Lieutenant Commander W.J. Wilson, RNR. One of the Australian-typeBathurst-class corvette/minesweepers,Bengal was one of four ships of her class that had been allocated to theRoyal Indian Navy. She only had one 3-inch gun (a 4-inch gun was not available), which made her firepower barely enough to protect theOndina fromsubmarines, let alone from enemy surface raiders. The two ships departed Fremantle on 5 November 1942, expecting a long but uneventful trip.[1]
On 11 November 1942 at 11:45 in the morning, naval authorities in Fremantle received an SOS signal sent out by theBengal, reporting that she and theOndina were under attack by tworaiders, identified as being Japanese, at position 19.38° South 93.5° East. The battle started when a lookout aboardOndina sighted an unknown vessel at about 12,000 metres (13,000 yd), bearing 270 degrees, followed by a ship of similar size.[1]
As no Allied ships were reported in the vicinity, the Allied sailors could only assume the ships bearing down on them were hostile and for some time these ships were even identified as Japanese aircraft carriers. On theBengal, the lookouts saw the two AMCs a few minutes later. The ships both made a 90 degree turn to starboard away from the enemy in a north-north-west direction.Bengal then turned and headed straight for the attackers, hoping to buy enough time for theOndina to escape. She opened fire at 1200 hours from 3,200 m (3,500 yd), followed by theOndina at 1205 from 8,000 m (8,700 yd). The sensible thing to do for theOndina was to obey the order to escape, but the captain decided to stay, as his ship, armed with a 4-inch gun, was still the more powerful of the two. In addition, theOndina could only do 12 knots (22 km/h; 14 mph) while the Japanese ships could make 21 knots (39 km/h; 24 mph).[1]
TheAikoku Maru under CaptainTamotsu Oishi, andHōkoku Maru under CaptainHiroshi Imazato, commenced firing at 1200 hours and soon straddled theOndina with their cruiser-armament. The first hit onOndina ripped off a part of the main mast, leaving only a stump. TheOndina herself had her answer ready: the third shell fired was a hit on the superstructure ofHōkoku Maru, but apparently with little effect.[1]
Content with the hit, the gun captain then ordered the gunners to concentrate their fire on the stern. A few moments later, a hit on the starboard torpedo mount turned theHōkoku Maru into a ball of red and yellow flames, and as the ship emerged from the smoke, she was listing heavily to starboard and simultaneously started to settle by the stern. The explosion ripped off the stern and threw her two floatplanes overboard, while massive fires raged in the superstructure.[1]
Hōkoku Maru was not built as a warship, and therefore did not have a sufficient number of watertight bulkheads. Shells toppled from their lockers as a result of the increasing list and threw sailors overboard. Men, covered with blood and suffering from burns, tried to fight the flames. Reports came in indicating large fires in the engine-room and the loss of all electricity. There was little hope of salvaging theHōkoku Maru, Captain Imazato could do nothing else than order "abandon ship".[1]
TheAikoku Maru picked up a total of 278 survivors from a crew of 354. Captain Imazato was one of the 76 killed during the action. There were no reports of damage or casualties aboard theAikoku Maru, which soon avenged her sister ship, scoring several hits onOndina. Nevertheless, her shells and torpedoes had little effect on the empty tanker, as the large number of watertight tanks could keep it afloat under the most difficult circumstances.Aikoku Maru also fired at theBengal, which had shortened the range to about 2,200 m (2,400 yd). One shell from the Japanese ship hit her in the forecastle, but did little damage. Her gunners had been firing continuously at the Japanese, claiming several hits but their ammunition supply was soon depleted. At 1245, her last shell had been fired and her captain decided there was little he could do for theOndina. He steamed away at full speed, chased by gun splashes. After laying a smokescreen, she took a hit in the stern which had no effect on her escape. The last the men aboardBengal saw of theOndina was her trying to evade the shells, continuously straddled by theAikoku Maru. A shell was seen hitting her abaft the bridge. Some time later, a second explosion was seen aboardHōkoku Maru, still burning and sinking. After leaving the scene,Bengal set course forDiego Garcia, where the captain reported theOndina and one enemy AMC sunk.[1]
Bengal's captain was right about one thing, theHokoku Maru had indeed sunk, but afterBengal had disappeared over the horizon,Ondina was still steaming around at full speed. As a tanker, she only had a limited ammunition supply.Aikoku Maru closed the range to 3,500 m (3,800 yd), and over the next few minutes scored several hits, one of which was observed by theBengal.Ondina herself only had twelve shells left, four of which she fired at theHōkoku Maru, the rest atAikoku Maru, apparently without scoring a hit. A last attempt to escape by dumping smokebuoys overboard was unsuccessful, and the captain ordered the crew to abandon ship to avoid further bloodshed. The engines were stopped, the lifeboats lowered and a white flag was hoisted, all under continuous fire from theAikoku Maru. A few moments later, Captain Horsman was killed by a piece of shrapnel from a shell hitting the bridge. Two lifeboats and two rafts were lowered into the water and later, another lifeboat was in the water with the remainder of the crew. Most of the crew (with the exception of officers and guncrew) were Chinese, and they had been troublesome during the whole action, refusing to provide any assistance to save the ship.[1]
Aikoku Maru approachedOndina, closing to about 400 m (440 yd) and fired two torpedoes to finish the ship off. Both left big holes in the starboard side, but did little to sink the ship itself. Its tanks had been empty and the ship remained afloat on the other, undamaged tanks, despite the 30 or 35 degree list.Aikoku Maru then changed course and the Japanese gunners opened fire on the drifting lifeboats. One sailor was killed, three others were badly wounded. One of them was a young British sailor named Henry, originally assigned to theBengal. Satisfied with the results,Aikoku Maru steamed away to pick up survivors fromHōkoku Maru. TheAikoku Maru came back once more, firing a torpedo which missed the tanker. She paid scant attention to the survivors, convinced theOndina was doomed.[1]
Meanwhile, the men in the lifeboats had given the deceased a seaman's burial and then exchanged thoughts about what to do next. Thefirst officer, Rehwinkel, wanted to return to the tanker, but only one man in the gun crew was willing to go with him. Most of the others were convinced theOndina was about to go down. Not without trouble, Rehwinkel managed to assemble a small number of men and returned to the ship, where counterflooding reduced the list. Inspection revealed that her engines were also still intact. Small fires were extinguished and the last crew members in the lifeboats were taken aboard after they were convinced there was no danger of sinking. The long leg back to Fremantle began. The lifeboats were patched up as well as possible, in case theAikoku Maru came back.[1]
The British sailor Henry was in very bad shape. He had a crushed leg and after two days the first officer was forced to send out a signal for help. The signal was sent uncoded, because the codebooks had all been thrown overboard when "abandon ship" was ordered. This unexpected signal caused a shock inColombo, as theOndina had been reported sunk and logically, the British suspected a Japanese trick. A request went out from Fremantle to report her position.[1]
Wary of a trap, theOndina did not reply. Without medical attention for her wounded, theOndina steamed towards Fremantle. On the 17th anAustralianPBY Catalina flying-boat was sighted, about 200 miles (320 km) northwest of Fremantle. The lookouts had reported a ship some time earlier and the Catalina was asked if that ship could provide much needed help. The unknown vessel proved to be a hospital ship where doctors immediately began a series of blood transfusions which succeeded in saving Henry's life.[1]
On 18 November, theOndina entered Fremantle after a journey only a few ships had experienced and even fewer had survived. The corvetteBengal had entered Diego Garcia the day before.Ondina remained in Australia as adepot ship until 1943, when she was finally repaired. BothBengal andOndina survived the war.[1]
In retrospect, this battle was not only a tactical success for the Allies, it also had strategic implications. The loss of theHōkoku Maru forced the Japanese to abandon raider warfare and subsequently the Imperial Japanese Navy did not try to break the lifeline again until early 1944 when a force of three heavy cruisersraided Allied shipping in the Indian Ocean.[1]
It remains uncertain as to which vessel fired the fatal shot that resulted in the destruction of theHōkoku Maru. Both theOndina andBengal claimed to have scored the vital hit, although the Japanese themselves thought it was theOndina. According to them, her shell hit the starboard torpedo launcher, causing the torpedo to explode. At the time, theBengal was given the credit, which was used by the British as propaganda in India, where they were struggling to keep control of the local population.[1] Nevertheless, for its actions during the battle, theOndina was given a rare Dutch distinction, theKoninklijke Vermelding by Dagorder, issued on 9 July 1948. Captain W. Horsman becameRidder in de Militaire Willemsorde der 4de Klasse posthumously and was Mentioned in Dispatches, while the gunner, Hammond, received theDistinguished Service Medal and the Bronzen Kruis. The captain of theBengal, Lieutenant-Commander Wilson, received theDistinguished Service Order, while others of his crew were also decorated.[1]
Aikoku Maru was converted into a high-speed transport and was sunk in February 1944 duringOperation Hailstone, the bombardment by American aircraft of the Japanese base at Truk in theSouth Seas Mandate.[citation needed]