WE MUST NOW GO BACK NINE MONTHS or so in time, to follow what had been happening in the Far East. It will be recalled, that in August 1944, the Eighth Submarine Flotilla was transferred to Western Australia to work with the US Navy and this chapter will be devoted to its operations. Maidstone, as told in Chapter XXV, arrived at Fremantle on 4th September and again as also related, her submarines followed her, all but three of them patrolling on the way. Telemachus, Spiteful, Sea Rover, Sturdy and Zwaardvisch had arrived by 7th September, Stoic, Tantivy, Sirdar, O19 and Storm by 20th and Tantalus by 27th. The Eighth Submarine Flotilla, after its move, remained under the administrative command of the British C-in-C, Eastern Fleet, but now came under the operational command of the Commander, Submarines of the US Seventh Fleet (Rear Admiral Ralph W Christie USN) who flew his flag ashore in Perth, Western Australia. Even the overall strategic directions, under which the submarines operated, changed. They were now in the South West Pacific Area under the Supreme Command of General Douglas MacArthur, instead of the South East Asia Area under Admiral Lord Louis Mountbatten. The orders issued to submarines on patrol by Admiral Christie were simple. They were to 'wage unrestricted submarine warfare' on Japan. The priority of targets was to be aircraft carriers, battleships, cruisers, supply ships, transports or tankers, destroyers and escort vessels in that order. Our submarines had to use American radio communications and ciphers and, to ensure that there were no misunderstandings; the British Staff Officer (Operations) of the Eighth Flotilla was attached to the operational staff of the Commander Submarines, Seventh Fleet in Perth.

By the transfer of the Eighth Flotilla to the South West Pacific area, the British hoped to be able to engage far more important targets than could be found in the Malacca Straits and so exert a much greater influence on the war with Japan. The substantial successes achieved by the American forces had, however, already greatly decreased the number of targets. Over the last two and three-quarter years, the US submarines alone had sunk no less than 810 ships totalling 3,577,523 tons. The Japanese merchant fleet, in spite of a considerable building programme, had fallen from a total of 5,996,607 tons at the outbreak of war, to 3,710,446 tons, which was already insufficient for them to sustain their forces overseas and maintain essential imports for the Japanese war economy. Soon after the Eighth Flotilla arrived in Fremantle, the US Forces landed at Leyte in the Philippines and this led to the naval Battle of Leyte Gulf. The Japanese Fleet left Lingga to take part and, after the battle, the survivors went first to Brunei Bay and then to Japan, and few ever returned south. All that was left in the southern area, based at Singapore, were four eight-inch gun cruisers, two of which were seriously damaged in the battle. Nevertheless the US Navy genuinely welcomed the co-operation of British and Dutch submarines in the South West Pacific. Although the British and Dutch submarines compared unfavourably with the American boats, which were faster, of much greater endurance and fitted with the anti-ship SJ radar and very high frequency radio, which made night pack tactics possible, the price was that they were very large and found it difficult to work in the shallow waters of the East Indies and Gulf of Siam. When the use of British submarines in the Pacific was first suggested to the US Navy in January 1943, Admiral King had welcomed them, especially the S-class, for working in the comparatively shallow Java Sea where conditions were difficult for the large US submarines. He also welcomed the T-class for operations in the South China Sea or farther north to the limit of their endurance. There is no doubt, too, that the US Navy admired the battle-worthiness and efficiency of both the British and Netherlands submarine arms.

Surprisingly a submarine base at Fremantle in Western Australia is no closer to the Java or South China Seas than Trincomalee in Ceylon. But for the apparent predilection of Admiral King for the S-class, it is therefore surprising that the Fourth Submarine Flotilla, composed entirely of T-class, was not sent instead of the Eighth, which was mostly composed of S-class. Even the US submarines had found it expedient to establish a fuelling station at Exmouth Gulf in Western Australia, some 700 miles closer to the Java Sea¹. The Malay Barrier, which the Americans call the southern chain of islands in the East Indies from Sumatra to Timor, could be entered by a number of straits. Allied submarines used three. The Sunda Strait between Sumatra and Java is narrow and shallow enough to be mined. The Lombok Strait between Bali and Lombok is ten miles wide and is too deep to be mined and so was normally the one used. The currents, however, were too strong for a submerged transit to the northwards. The third strait used for access to the Flores Sea was to the east of Ombai and north of Timor. It was planned for the S-class, using Exmouth Gulf to refuel, to spend a fortnight in the Java or Flores Seas for a total patrol time of twenty-eight days. The figures for the T-class were three weeks on patrol for a total at sea of thirty-five days. A period of twenty-one days was spent in harbour between patrols by both T and S-classes.

She then withdrew submerged through the Lombok Strait and reached Fremantle after refuelling at Exmouth Gulf and having been 37 days at sea, which was a record for an S-class submarine to date.

Tantivy reached the Macassar Strait by 19th October and had developed a disturbing rattle in her port propeller. Her Engineer Officer solved the problem by using a Davis Escape Apparatus to dive and unscrew a loose rope guard, which was the trouble. Two days later, she sighted no less than twenty-one local craft and sank eight of them by gunfire, all carrying nickel ore, before she was forced to dive by an aircraft. Two hours later, she got another one and next day, a 150-ton coaster and five more schooners as well. During the last gun action, Tantivy got into shallow water and was bombed and machine-gunned by an aircraft while in only four fathoms. She tried to dive and bumped and wriggled herself into deeper water and the bombs fortunately missed her. The same day, she sighted a 500-ton coaster and decided to expend a leaking torpedo from one of her external tubes. She fired at 3000 yards and it is not surprising that she missed. Tantivy then surfaced and engaged with her gun, in spite of the fact that a Japanese corvette was in sight eight miles away. She drove the coaster ashore on fire and then made for deep water and dived. The corvette searched but failed to make contact and was later joined by another anti-submarine vessel, which searched inshore and was suddenly seen to blow up and sink. This was near the position where her torpedo, which missed the coaster, would have ended its run. It had a CCR pistol set to non-contact and it is quite possible that it fired as a ground mine. On 23rd, Tantivy sank another schooner by gunfire and on 25th she came upon two coasters at anchor. She fired a torpedo but it exploded prematurely and so she had to surface and complete their destruction by gunfire. Next day she met a large coaster and, being now very short of gun ammunition, fired two torpedoes at her from the surface. Both torpedoes circled and were avoided with difficulty and then one of them prematured. She was then able to drive the coaster ashore with the few rounds left for her gun. Tantivy had now lost confidence in her torpedoes and, with no ammunition left, she set course for home through the Lombok Strait eleven days early. On arrival, she was rightly taken to task for leaving patrol early without reporting her situation as she could have been used for reconnaissance or air-sea-rescue.

Storm, on her arrival in the Flores Sea on 20th October, was bombed by an aircraft and a near miss caused minor damage. Up to the 29th, she sighted no worthwhile targets and, on that day, being scheduled to return, obtained permission to stay out an extra three days. These she spent very profitably in the Gulf of Boni operating against the nickel ore trade from the port of Pomelaa. She sank two schooners on 29th and two more on 1st November, placing the crews in other schooners. On 2nd November she sank six schooners, taking off their crews numbering twenty-eight. These were placed in a seventh schooner, which was forced to jettison its 20-30 ton cargo of ore. A final victim was sunk that night and its crew, including a woman and child, were placed in a smaller vessel, which had to be let go. Storm then set course for home by the Lombok Strait, which she intended to transit at night on the surface. She was, however, forced to dive by the presence of patrol vessels but was not detected. In this patrol, Storm set a distance run record for an S-class patrol of 6210 miles and had to fuel at Exmouth Gulf on her way back. Lieutenant Commander Young was complimented on his return, not only for his success against the ore traffic, but also for his humanity, not a single casualty being caused.

Operation 'Rimau', the attempted attack on shipping in Singapore by Commandos using electrically propelled submersible canoes, was dealt with in Chapter XXV. It was not known at this time that disaster had overtaken the expedition and the plan was still to recover the party from Merapas Island early in November. This was originally to have been done by Porpoise detached from the Fourth Flotilla for the purpose. She, however, was still in dock at Fremantle and her repairs were not complete. Tantalus (Lieutenant Commander HS Mackenzie DSO* RN), therefore, was selected to carry out the recovery and to combine this with a patrol in the South China Sea. She sailed from Fremantle on 16th October, fuelled at Exmouth Gulf, passed through the Lombok Strait on the surface at night without difficulty and was off the Singapore Strait by 28th. On the same day she sighted an escorted merchant ship but was unable to get into position to fire before the enemy entered the strait. On 30th, she met a U-boat but the sighting was mutual and she was again unable to attack. On 1st November, the US submarine Gurnard reported two ships at anchor off Miri in North Borneo, which were expected to sail for Singapore. Tantalus took up a position to intercept but the ships got past her in poor visibility and rain. Next day, during the afternoon, however, she sighted an eastbound convoy but there were still heavy rainstorms about. She managed to get in a shot at a fleeting target from inside the screen at close range. She fired two torpedoes at about 400 yards and hit and sank Hachinju Maru of 1918 tons. The escorts never gained contact and there was no counter attack. Tantalus would have liked to pursue the convoy but was ordered to take up a position for air-sea-rescue duty off the east coast of Malaya. On 8th, she sighted a merchant ship with escorts and approached to attack. One of the escorts, however, detected her before she could fire and forced her deep dropping nine depth charges. This incident was in only 60 feet of water and two of the charges were close. Fortunately she was able to bounce along the bottom into deeper water and was undamaged. On 11th, Tantalus sank Palang Maru of 200 tons with her gun and picked up eleven survivors who were transferred to a junk. The time had now come to recover the twenty-five strong 'Rimau' party from Merapas Island but she had fifteen torpedoes on board and provisions and water for another fortnight. She therefore obtained permission to defer the recovery until 21st November. However she did not meet any more targets and no survivors of the 'Rimau' party were found on Merapas, so Tantalus started her homeward voyage. On 27th in the Java Sea, she sighted another escorted merchant ship but there were rainstorms to complicate her attack and she 'missed the DA'. She succeeded, however, in getting away four torpedoes from fine on the quarter at a range of 1500 yards. One torpedo was seen to premature and counter mined another, which attracted the attention of the escorts that nevertheless were unable to gain contact. The southward passage of Lombok Strait was made submerged by day and Tantalus arrived at Fremantle after 52 days at sea and having run 11,539 miles, which was the longest patrol made by a British submarine to date during the Second World War.

Stoic (Lieutenant PB Marriott DSO RN), who had arrived in the Far East in February 1944 and had made five patrols in the East Indies as well as one in the South West Pacific, was already due for a refit in the United Kingdom. There was, however, time for her to make one more patrol on her way to Colombo. She left Fremantle on 2nd December and was ordered to patrol south of the Sunda Strait. This patrol area had been vacant since Sirdar had left on 28th October. The Japanese battleships Ise and Hyuga were, however, known to be operating in the South China Sea from Cam Ranh Bay in French Indo China and it seemed prudent to take this opportunity to block this exit. Stoic spent a week there and on 16th, her last day, sighted a ship with a single escort. She was able to fire four torpedoes from a range of 3000 yards in heavy rainstorms, hitting and sinking Shoei Maru of 1986 tons. The counter attack was ineffective and Stoic proceeded on her way to Trincomalee and home. Storm (Lieutenant Commander EP Young DSO DSC RNVR), on her second patrol, was ordered to the Macassar Strait again and sailed on 4th December, calling at Darwin and passing east of Timor. On arrival in her area, she met a small merchant ship in convoy and fired three torpedoes at a range of 4000 yards in heavy rainsqualls, but missed. The counter attack was ineffective. She sighted no more targets before leaving patrol on 29th. Storm returned through the Lombok Straits on the surface at night in bright moonlight and was detected, forced to dive, and was depth charged by a destroyer in the approaches. She shook her off, however, and made a successful transit submerged by day with a southerly set to help her.

Telemachus (Commander WDA King DSO DSC RN), for her second patrol, was sent on 4th December, to patrol east of Singapore. Because of the difficulties experienced by Zwaardvisch in the Lombok Strait, she was routed, after refuelling at Exmouth Gulf, by the Ombai Strait, which added a thousand miles to her passage. In spite of the presence of the Japanese battleships Ise and Hyuga at Lingga, she saw nothing and had a blank patrol. She returned to Fremantle through the Lombok Strait after 48 days at sea and running 9307 miles. O19 (Luitenant ter zee 1e Kl JF Drijfhout van Hooff) was ready again by 18th December and embarked 40 mines to lay a field off Batavia. It was hoped that this field would catch enemy U-boats that were now believed to be using the Sunda Strait on their way to the Indian Ocean. She was routed by Darwin and east of Timor. The minefield was successfully laid on 3rd January and she was then ordered to search along the north coast of Java. On 5th January she made a night attack with four torpedoes on a small merchant ship but failed to secure a hit. Two days later she sighted an escorted vessel just before dusk and made a submerged attack with three torpedoes at a range of 800 yards and sank Shinko Maru No 1 of 935 tons. O19 anticipated a counter attack and in taking evasive action hit the bottom in 11 fathoms. She was then subjected to an attack of five very close charges, which caused a great deal of damage. The cooling plant then leaked carbon dioxide gas and the engine room had to be abandoned and shut off. Four hours later, the enemy was still in the vicinity. O19, however, succeeded in sneaking away on the surface. The damage was extensive and she decided to return to base and to take a route by Darwin, rather than risk the passage of the Lombok Strait. O19 then had more trouble with her after hydroplanes, which were patched up at Darwin. On arrival at Fremantle on 24th January, she had to be taken in hand for new hydroplanes to be fitted and this kept her out of action until April.

At the end of 1944, Rear Admiral James Fife Jr USN arrived to take over command of the Seventh Fleet submarines from Admiral Christie. The Eighth Flotilla especially welcomed this appointment. Admiral Fife had been an observer with the British submarines earlier in the war and had made a number of patrols in them. He was therefore particularly suited to command this Anglo-Dutch-American force. In November 1944, the Admiralty informed the US authorities of the proposed composition of the British Pacific Fleet. This included the Fourth Submarine Flotilla as well as the Eighth and it was scheduled to arrive in January 1945. With the American liberation of the Philippines now in progress, it was hoped that both the Fourth and Eighth Flotillas could be moved up to a base there so as to be able to operate further north and to cut down the present long periods spent on passage. With the formation of the British Pacific Fleet in November, the administration of the Eighth Submarine Flotilla was transferred to its C-in-C. Admiral Sir Bruce Fraser, the newly appointed C-in-C, did not wish the Fourth Flotilla to move to the Pacific until a base was available for it in the forward area. He wished it to remain in the East Indies for the present and its transfer was postponed for three months, until April 1945. The US submarines at Fremantle also wished to move to the Philippines as soon as possible. American forces landed in Luzon in early January and captured Subic Bay by the end of the month. Admiral Fife flew up to the Philippines to arrange matters in the New Year.

By the end of 1944, the Eighth Flotilla had been operating in the South West Pacific for four months. Its submarines had now made two patrols each. In general it can be said that whereas the length of patrols had doubled, the sinkings were no better than they had been in the Malacca Strait. All British submarines were now fitted with air conditioning machinery and it can also be said that efficiency and morale had not fallen off with the longer patrols. The improvement in conditions ashore in Western Australia between patrols, as compared with wartime Ceylon, was more than compensation. They had, however, only made eighteen torpedo attacks expending 56 torpedoes and these had sunk U168 and Itsukushima but only three small merchant ships totalling 4,389 tons. An auxiliary minelayer was also damaged. Fifty-nine coasters, schooners and other small craft were sunk by gunfire and another four damaged. None of our submarines was lost but the opposition was by no means feeble. Two submarines were depth charged so heavily that they had to return to base and five others were subjected to close and noisy counter attacks, while three submarines were bombed but missed by aircraft. There were three cases where our submarines were driven off by return gunfire or shore batteries.

On this same day, a reconnaissance aircraft reported Ise and Hyuga northbound to the east of Singapore with a cruiser and three destroyers in company. Tantalus at once moved eastwards to intercept. Tradewind did not receive the report until she surfaced that night and then also moved eastwards at full speed. Spiteful had by now left patrol for Fremantle. On the morning of 11th February, Tantalus was east of the Anamba Islands and just after midday sighted the 'pagoda' masts of Ise and Hyuga to the southeast at a range of 17 miles. They were steering to the north north-eastwards at moderate speed and Tantalus attempted to intercept at full speed on the surface. She could only shadow, however, and after an hour and a half, she was forced to dive by a low flying aircraft, which dropped two bombs fairly close. Two hours later she was able to surface and make an enemy report by wireless. The enemy report was picked up by Tradewind telling her that the enemy had passed her and was well to the northwards. Tantalus pursued on the surface but did not sight the enemy again. There were, however, four US submarines still ahead of the enemy. Next day Blackfin, in a position southeast of Saigon, sighted the enemy and shadowed for two hours. Charr also made contact and also shadowed but then lost contact too. On 13th February, Blower sighted the enemy squadron and fired six torpedoes at ranges from 1800 to 2800 yards and claimed two hits. Half an hour later Bergall fired another six torpedoes at 4800 yards and thought she hit with one of them. Both submarines, however, missed and the Japanese squadron went on northwards unharmed. This was the only occasion in the Second World War that a British submarine sighted units of the Japanese battlefleet. Tantalus, Tradewind and Spiteful all returned to Fremantle by the Lombok Strait without difficulty. Tantalus broke her own record and was at sea for 55 days running 11,692 miles and Spiteful was out for 37 days running 6873 miles. A cyclone in the Indian Ocean had struck Exmouth Gulf and the fuel barge was out of action. Tantalus just got to Fremantle with less than 5% of her fuel remaining.

Meanwhile, to add to the problems caused by the cyclone, a serious incident occurred in Fremantle. On 17th January, an oil fire broke out in the harbour between the wharf at which the three depot ships were lying and a liner berthed next to Maidstone. It soon got out of control and spread rapidly to the wooden jetty. The two American tenders, having diesel engines for propulsion, were able to get under way and leave harbour and anchor outside. Maidstone's steam turbines, however, were at twenty-four hours notice. Nevertheless steam was raised in forty-five minutes and the ship was moved by tugs in the nick of time but not before the paintwork on Maidstone's side was on fire as far aft as the well deck. The liner sank at her berth and the fire was eventually extinguished allowing the three depot ships to return alongside. Farther north, arrangements were made for submarines to fuel at Onslow instead of Exmouth Gulf.

At the end of January 1945, Captain(S/m) Four flew down to Fremantle to discuss the disposition of submarines with the Commander, Submarines Seventh Fleet and with Captain(S/m) Eight. All three then went on to Sydney for meetings with the C-in-C, British Pacific Fleet and his staff. Admiral Fife subsequently flew on to the Philippines to finalise arrangements for the forward move of himself and his submarines to Subic Bay, north of Manila, which had fallen into American hands on 30th January. Olongapo in Subic Bay had been a peacetime base for American submarines before the war, and the Bay had just been swept and found to be clear of mines. It was decided that the Eighth Submarine Flotilla should move up to Subic Bay in April, and that it should be relieved at Fremantle by the Fourth Submarine Flotilla from Trincomalee.

Four more submarines set out on patrol from Fremantle in January. Tantivy (Lieutenant PH May RN) was due for refit in the United Kingdom and was, as was becoming customary, sent to patrol south of the Sunda Strait on her way to Trincomalee. She sailed on 14th January. The newly arrived Spark (Lieutenant DG Kent RN), who had made one patrol in the Malacca Strait, sailed two days later and was sent to patrol in the west Java Sea and was able to refuel at Exmouth Gulf before the cyclone hit at the end of the month. Zwaardvisch (Luitenant ter zee 1e Kl HAW Goossens) was despatched on 30th January on her third patrol to cruise in the Java and South China Seas and finally Storm (Lieutenant Commander EP Young DSO DSC RNVR) sailed on the last day of January, also to refit in the United Kingdom and to relieve Tantivy south of the Sunda Strait on the way. Storm ran into the cyclone on the west coast of Australia and, after the damage to the fuelling facilities at Exmouth Gulf, was ordered to go to Onslow for fuel. She then arrived on the west coast of Sumatra on her way to Trincomalee without sighting anything. On 3rd February, Tantivy off Panjang on the Sumatra side of the Sunda Straits met a tug towing two coasters and despatched all three by gunfire. She then decided to fire torpedoes into the harbour at other coasters inside. She got one torpedo away but it hit nothing and she then ran hard aground where the chart showed ten fathoms. It was dusk but she was clearly visible from the shore. It took two hours pumping out tanks, working her motors and firing four torpedoes to lighten her, before she was free. She damaged both propellers in the process and was lucky that the enemy did not interfere. However she got safely away to Trincomalee where she was docked for repairs. Spark made a night surface passage through the Lombok Strait without difficulty. She saw nothing on the north coast of Java for a week and then on 1st February off Semarang, she fired four torpedoes from periscope depth at a range of 900 yards at a coaster towing a lighter. She was, however, in very shallow water and three of the torpedoes hit the bottom. So did Spark immediately after firing, so she surfaced and sank both coaster and lighter by gunfire. Shortly afterwards, a tug was also sunk by gunfire. A small ship then came in sight and at once beached herself. She fired a torpedo at her at a range of 5000 yards but it missed and the enemy backed away and escaped into a bay. A coaster that then appeared also beached herself. Spark fired 58 rounds at her causing some damage but then an aircraft came in sight and she had to dive, the aircraft dropping two bombs, which missed but were close. On 8th February, a torpedo boat was sighted and attacked with four torpedoes at a range of 2200 yards, but she saw the tracks and counter attacked down them with sixteen depth charges and hunted for Spark until well after dark without gaining contact. On her way back to Fremantle, she encountered air patrols in the Lombok Strait but made a successful transit submerged by day.

In late February and early March, A(S) visited the Far East as has already been mentioned in Chapter XXVIII. He was able to discuss the situation, not only with Captains(S/m) Two, Four and Eight, but with the Commander, Submarines Seventh Fleet and the C-in-Cs in the East Indies and of the British Pacific Fleet. The move of the Eighth Flotilla to Subic Bay in the Philippines and of the Fourth Flotilla to Fremantle, already arranged, were confirmed and also a redistribution of submarines between them. The Eighth Flotilla was to consist entirely of S-class and the Fourth Flotilla of long range T-class with the minelayers Rorqual and O19. The Second Flotilla at Trincomalee would have three short-range T-class and six S-class. Although not specifically mentioned as a result of these discussions, it was clear that the thirty odd submarines in the Far East, were all that could be usefully employed, and that there was little point in trying to reach the figure of forty laid down as desirable in 1944. Nevertheless all new and refitted T-class were to be sent east as well as all the new A-class. Only sufficient S-class would be sent to keep up a strength of seven in the Second Flotilla and six in the Eighth Flotilla. With these operational matters settled, it was now possible to plan in detail the supplies, torpedoes and ammunition required by the three flotillas, which were entirely a British responsibility.

The four submarines that left for patrol from the Eighth Flotilla at Fremantle during March were all comparative newcomers. Tudor (Lieutenant SA Porter DSC RN), although a veteran of five patrols in the Malacca Strait, had only just arrived at Fremantle and left on her first patrol in the South West Pacific on the 7th. Stygian (Lieutenant GS Clarabut DSO RN) had also made five patrols in the Malacca Strait and left on her first from Fremantle on 15th. Spark (Lieutenant DG Kent RN) and Tradewind (Lieutenant J Nash DSC RN) left on their second patrols in this area on 14th and 22nd respectively. The two T-class were sent to the South China Sea using the Sunda Strait and the S-class to the Java and Flores Seas after fuelling at Onslow. Tudor sighted patrol vessels in the Sunda Strait, but got through without difficulty and went on her way to her patrol area off the Natuna Islands to the northwest of Borneo. On 22nd March she sighted a convoy of two ships with three escorts. Tudor was broad on the bow and went deep to close at speed. She fired a salvo of four torpedoes at a range of 3000 yards but it was glassy calm and they were seen and avoided. She was counter attacked and hunted for four hours, but not very effectively. She then made for a position south of Great Natuna Island where she hoped to be able to contact the convoy again. An American submarine had the same idea and was seen to dive by Tudor just before the convoy came in sight again. Tudor had to make another high speed dash submerged to get into position but then the convoy altered course towards her and she found herself very nicely placed. Just as she was about to fire, however, the escorts turned towards her and the convoy made an emergency turn away. It was soon clear that it was the American submarine that they had detected and the counter attack was watched by Tudor through her periscope. Both submarines shook off the Japanese escorts by using a density layer, but the convoy escaped. Tudor then patrolled in the Miri-Brunei area until 31st March when she was ordered to rendezvous with the US submarine Hardhead, which had Admiral Fife on board. Tudor received her mail and some fresh provisions and rendered a report of her proceedings so far to the Commander Submarines Seventh Fleet in person. On her way back, she patrolled for three days off Batavia and returned by the Sunda Strait, reconnoitring Christmas Island on her way to Fremantle.

Spark made a northbound transit of Lombok Strait submerged by day and then searched the north coast of Sumbawa for a week without result. On 29th, east of the Postillon Islands, she fired four torpedoes at a coaster at a range of 1100 yards and missed, so she surfaced and sank it by gunfire. On 31st, she repeated this performance exactly, firing four more torpedoes at a coaster, this time at 3500 yards and missing again. This coaster was also sunk by gunfire. On 4th March, Spark sighted the Japanese light cruiser Isuzu with four escorts steering southeast towards the Sape Strait. She fired her last four bow torpedoes but at the long range of 7000 yards in a calm sea and they missed or were avoided. As soon as the enemy was out of sight, she surfaced and made an enemy report that was picked up by the American submarine Gabilan, one of a wolf pack of three working south of Celebes. The wolf pack had already seen Isuzu but none of them were able to get within torpedo range. After dark, Besugo, of the wolf pack, followed the enemy formation through the Sape Strait using her SJ radar and picked off one of the escorts. Spark had only her one stern torpedo remaining but was ordered to join the wolf pack and act under the orders of the senior officer in USS Charr. She was, however, unable to communicate by voice radio, so took up a position north of Sape Strait to intercept the enemy should they come north again. Charr and Gabilan patrolled north of Bima Bay in Sumbawa⁷. Isuzu and her escort came north through the Sape Strait on 6th April and were seen at long range by Charr, Gabilan and Spark. Isuzu, as expected, entered Bima Bay. She left again during the night and was detected by radar by both Charr and Gabilan. Gabilan attacked before daylight and secured a hit. As it got light, both Charr and Spark sighted Isuzu going very slowly and circling. Charr fired six torpedoes, three of which hit and sank Isuzu, Spark watching through her periscope. She was then recalled and withdrew through the Sape Strait.