Action Of 8 June 1945

The action of 8 June 1945, sometimes called the Sinking of ''Ashigara'' was a naval action that resulted in the sinking of the Imperial Japanese Navy (IJN) heavy cruiser by the British submarine . ''Ashigara'' was transporting Japanese troops from the Dutch East Indies for the defence of Singapore and its loss caused many casualties.

The voyage of ''Ashigara'' was revealed to the Allies by Ultra decrypts, which enabled Rear-Admiral James Fife, the US commander of submarines, South-West Pacific, to lay an ambush. ''Trenchant'' and patrolled on either side of the Hendrik Klippen Shoal at the north end of the Bangka Strait, between Sumatra and Bangka Island. The British submarines were alerted by sighting reports from US submarines.

''Trenchant'' fired a long-range salvo of eight torpedoes at ''Ashigara'', from a tactically-awkward angle but the Japanese cruiser was too close to the Sumatran shore to turn away. The cruiser had to accelerate and turn towards the torpedoes but could only evade three of them. The five hits caused a big fire and ''Ashigara'' took on a list to starboard before capsizing. The destroyer rescued survivors but 1,350 men of the crew and troops being transported were killed.

Background

Japanese navy reorganisation

On 5 February a new command, the Tenth Area Fleet (Vice-Admiral Shigeru Fukudome), with the 13th Air Fleet, was separated from the South-West Area Fleet. The main force of the Tenth Area Fleet was the Second Diversionary Attack Force with the 4th Carrier Squadron, comprising the battleship carriers ''Ise'' and ''Hyuga'' and the 5th Cruiser Squadron with the heavy cruisers ''Ashigara'' and ''Haguro''. ''Ise'' and ''Hyuga'' were recalled to Japan and sailed from Singapore on 10 February with three destroyers, leaving the Tenth Area Fleet with only the 5th Cruiser squadron and the elderly destroyer .

Japanese strategic withdrawals

In early 1945 the Japanese began to remove distant garrisons in the South-West Pacific to reduce the defence perimeter to the Celebes, Borneo, Java, Sumatra and hold it for as long as possible, with Indo-China and Malaya in the centre of the defensive zone. ''Sho'' (Akiraka) was the withdrawal of troops from the Andaman and Nicobar islands to Singapore, ''Chi'' was the transfer of troops from Singapore to Indo-China, Transportation No. 10 was the transfer of the 48th Division from Timor and ''Ho'' was an evacuation of troops from Borneo and Surabaya that was not undertaken.

East Indies Fleet

When the British Pacific Fleet had been established in November 1944, the ships left in the Indian Ocean became the East Indies Fleet (Admiral Arthur Power) on 19 November. The fleet consisted of the 3rd Battle Squadron and the 5th Cruiser Squadron along with escort carriers, assault carriers, a ferry carrier and over thirty destroyers. British submarines of the 8th Submarine Flotilla had been based at Fremantle in Australia since September 1944 in the US 7th Fleet and had been patrolling the Java Sea, the south-west Pacific and the China Sea. In April 1945, the 8th Flotilla moved to Subic Bay in the Philippines and was replaced at Fremantle by the 4th Flotilla, there being 38 British and Dutch submarines in the Far East.

Prelude

Operations Transport 10 and 11

Operation Transport No. 10 and Operation Transport No. 11 to bring Japanese army troops from the Lesser Sunda Islands to Singapore via Batavia (now Jakarta) continued in June 1945. On 3 June ''Ashigara'' and ''Kamikaze'' left Singapore to transport the troops from Jakarta, departing for Singapore on 7 June, with about 1,600 troops and of supplies embarked on ''Ashigara''. No air cover was forthcoming as the Japanese Army considered the moves a purely naval matter but reconnaissance flights of the Bangka Strait were flown from bases in western Java. ''Ashigara'' was escorted by the destroyer ''Kamikaze'', which had survived the Japanese defeat at the Battle of the Malacca Strait (15–16 May). Their route was north from Jakarta, then north north-west through the Bangka Strait between Sumatra and Bangka Island, thence north to Singapore.

Allied submarine operations

In June, Ultra decrypts of Japanese naval messages revealed that ''Ashigara'' and ''Kamikaze'' were to move troops of the 48th Division from Jakarta to Singapore. The commander of submarines South-West Pacific, Rear-Admiral James Fife USN, ordered an ambush to be laid. The observed the departure of ''Ashigara'' and ''Kamikaze'' from Jakarta but was unable to manoeuvre into an attack position. ''Bluebacks contact report was passed on to (Commander Arthur Hezlet). With some reluctance, Fife allowed ''Trenchant'' into the Bangka Strait, despite its dangerous shoals, currents and the presence of an Allied minefield. In company with the submarine (Lieutenant G. C. Clarabut), ''Trenchant'' took up position on the northern approaches of Bangka Strait, ''Trenchant'' just inside the strait, south of Hendrik Klippen Shoal, while ''Stygian'' patrolled north of the shoal. Both submarines were on the surface; to get into position, ''Trenchant'' had to negotiate a minefield laid earlier by the Royal Netherlands Navy submarine .

Action

On 8 June 1945 at ''Kamikaze'' was spotted by ''Trenchant'', which in turn was spotted by the Japanese destroyer at ''Kamikaze'' opened fire on ''Trenchant'' to no effect and ''Trenchant'' fired a torpedo from her stern tubes but ''kamikaze'' increased speed and the torpedo missed. ''Trenchant'' immediately sent a contact report to ''Stygian'', which was patrolling to the north-west of the Bangka Strait, reporting that she had been detected by the destroyer, then changed position to east of the shoal and dived at Hezlet spotted ''Kamikaze'' again at heading north but disappearing from sight at

''Stygian'' saw star shells fired by ''Kamikaze'' at during the short engagement with ''Trenchant'' and also received the contact report. She remained north of the shoal, judging correctly that ''Trenchant'' was clear of the Japanese, since there was no further gunfire and no depth charge detonations had been heard, then dived at At ''Kamikaze'' was seen heading north, along with patrolling Japanese aircraft. At after ''Kamikaze'' changed course back to the south, ''Stygian'' fired two torpedoes at a range of but the torpedo tracks were spotted and evaded. ''Kamikaze'' attacked the submarine with depth charges, causing minor damage to ''Stygian'' but then lost contact, the sound of depth-charge explosions receding from the submarine.

Hezlet spotted the masts and upper works of ''Ashigara'' through his periscope at bearing 177 degrees at a range of , heading north-west on a course of 330 degrees at a speed of . ''Trenchant'' did not close the range, assuming that ''Ashigara'' would come closer to her by taking the more open water east of the shoal (closer to Bangka Island) but the heavy cruiser passed through the restricted water west of the shoal, closer to the Sumatra coast. It soon became clear to Hezlet that he could not reach a firing position closer to ''Ashigara'' than , almost at the maximum range of his torpedoes.

At such a distance, Hezlet had quickly to calculate a firing solution before the opportunity disappeared. At ''Trenchant'' fired a full bow salvo of eight torpedoes from 30 degrees abaft (towards the stern) of the cruiser's starboard beam at a range of aimed individually from a quarter of length ahead to a quarter of a length astern. Because of the Sumatran shore to port, the navigator on ''Ashigara'' could only attempt to change course to starboard by 120 degrees and increase speed to to comb the torpedo tracks as the troops on deck watched the torpedoes approaching. Three minutes later, five torpedoes struck ''Ashigara'' on the starboard side, one under the aft turret, one near the bow, then one amidships; two more torpedoes hit through thick smoke. The bow of ''Ashigara'' was blown off, the fo'c'sle deck smashed and the ship set on fire.

''Trenchant''s company queued to view through the search periscope but it was seen and fired on by ''Ashigaras anti-aircraft gunners. Hezlet then turned ''Trenchant'' to bring her stern tubes to bear and fired two more torpedoes at that missed. Torpedoes from ''Ashigara'' aimed at ''Trenchant''s periscope also missed. The fire caused by the first hits had spread rapidly through ''Ashigara'', causing a huge pall of smoke which obscured Hezlet's view. ''Kamikaze'' had returned to the area and dropped three patterns of depth charges but these were no closer than from ''Trenchant''. ''Ashigara'' capsized to starboard at at 1° 59' S 104° 57' E and ''Kamikaze'' began to rescue survivors, assisted by two local vessels. ''Trenchant'' remained submerged and escaped to the north of Bangka Strait, returning to Subic Bay, Philippines on 20 June 1945, followed by ''Stygian'' on 27 June 1945.

Aftermath

Japanese losses in the sinking severe, out of 1,600 troops, only 400 were rescued along with 850 of her crew, including Captain Miura and Vice-Admiral Hashimoto, the commander of the 5th Cruiser Squadron. ''Ashigara'' had been the last big Japanese warship in the area, after the cruiser was sunk during the Battle of the Malacca Strait a month earlier, by British destroyers. After her sinking, ''Kamikaze'' remained the only efficient ship left to the Tenth Area Fleet. The Tenth Area Command remained, Vice-Admiral Shin'ichi Ichise, left to command nothing more than minesweepers, anti-submarine ships and small craft. The sinking of ''Ashigara'' earned Hezlet a bar to his DSO and the U.S. Legion of Merit. ''Trenchant'' flew the Jolly Roger as a tribute to her success when she reached her base at Trincomalee. In 1965, Richard Compton-Hall described the sinking ''Ashigara'' at such long range, from a tactically awkward position, a considerable achievement.

See also

* List by death toll of ships sunk by submarines

Notes

References

Bibliography

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Further reading

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External links

IJN ''Ashigara'': Tabular Record of Movement

{{DEFAULTSORT:Action of 1945 06 08
Conflicts in 1945
Maritime incidents in June 1945
World War II naval operations and battles of the Southeast Asia Theatre
A
Naval battles of World War II involving Japan
Java Sea
Submarine warfare in World War II
June 1945 in Asia