The Royal New Zealand Navy
CHAPTER 14 — Anti-Submarine Policy
FROM time to time during the pre-war years the Admiralty had issued memoranda regarding the provision of auxiliary minesweeping and anti-submarine vessels in the event of a war in Europe or with Japan. In February 1939 it indicated that New Zealand should provide for twenty-four such vessels. The reply was made that shortly before the international crisis of September 1938 the New Zealand Naval Board had reviewed its mobilisation instructions and the policy relating to the provision of auxiliary minesweeping and anti-submarine vessels ‘in the light of Dominion local defence requirements and the capacity of the shipping industry to meet demands made upon it in the event of an emergency’.
The Naval Board said that it was not in a position to meet the manpower requirements of a policy based on the Admiralty memoranda without drawing on active-service and trained reservist personnel ‘who should be made available for more important service elsewhere’. New Zealand ports would be kept open by a flotilla of auxiliary vessels to be operated ‘in accordance with the dictates of the general situation’. The number would, at first, be six, later increased to nine, armed with 4-inch guns and depth-charges. They would serve a dual purpose as minesweeping and anti-submarine vessels, but they would not be fitted with asdics, ‘unless the circumstances call for such action at a later stage.’ This policy would be applied ‘whether or not a war eventuates in the Far East’.1
1 Naval Board memorandum to Admiralty, 20 February 1939.
In August 1940 Parry directed the Government's attention to the ‘lamentable unpreparedness of New Zealand to meet attacks on shipping or minelaying by enemy submarines.’ He pointed out that, though Germany and Italy had no Pacific possessions, there was little to prevent their using unfrequented anchorages as bases and the possibility of Japan's conniving at the use of her islands could not be overlooked. It was unlikely, though not impossible, that German or Italian submarines would appear in New Zealand waters. But if Japan entered the war, her submarines could operate here from their own bases in the mandated islands. Their probable plan would be to attack shipping in focal areas and lay mines off harbour entrances, but the possibility of attacks on shipping at undefended roadstead ports had also to be considered.
Shallow water would prevent submerged submarines entering Auckland, Wellington, and Lyttelton harbours, where the existing defences were probably sufficient to prevent their entering on the surface. The entrances to Hauraki Gulf confined shipping to three channels, each approximately ten miles wide. The depths were suitable for submarines to operate submerged and lay contact mines. Under present circumstances shipping was confined to one channel1 which, therefore, was not only extremely vulnerable but relatively congested. It was of the utmost importance that these approaches should be kept free from submarine activities since Auckland was a major port as well as the naval base.
The immediate approach to Wellington was not ideal for mining owing to bad weather and strong tides which were likely to break mines adrift from their moorings. The east and west approaches to Cook Strait, however, were important focal areas for coastal and overseas shipping. The approaches to Lyttelton were suitable for submerged submarines for a distance of 40 miles from Godley Head. The direct route from Lyttelton to Otago was all in mineable waters. The approaches to Timaru and Oamaru were too shallow for submerged submarines, but mines could be laid from the surface and there was nothing to prevent even a submarine shelling either of these ports, or Dunedin from the southward. Other ‘outports’ were similarly liable to attack, those used by overseas shipping being probably the most tempting targets. Submarines could work submerged in Foveaux Strait, but the strong tidal stream would greatly reduce the efficiency of contact mines. North Cape and East Cape were also vital focal areas for shipping.
Mobile defence against submarines was provided by patrol vessels fitted with asdic and depth-charges, or with the latter only. Aircraft also had considerable anti-submarine value. The only effective means of locating a submerged submarine was the asdic, which gave a fairly accurate range and bearing and had a normal effective range of some 2500 yards.
But there were no asdic-fitted vessels in New Zealand, no asdic equipment, and no trained SD ratings.1 The only vessels fitted with depth-charges were the minesweeping trawlers which were too slow to be of any real value against submarines. The few available aircraft, which were not designed or trained for the work, could carry out anti-submarine patrols, but they were not sufficient to protect ships from attack by submerged submarines.
Three minesweeping or anti-submarine vessels were building in Scotland, but their delivery was uncertain. Commodore Parry suggested that, if some of the local defence vessels building in Australia could be got, the demand for coastal vessels would be reduced. The building of trawlers in New Zealand was being considered, but these would make indifferent anti-submarine vessels because of their slow speed and it would be a long time before they materialised. Inquiries were also being made into the possibilities of fast motor-boats which should be fitted with asdics. The hulls could be built in New Zealand and the engines imported.
The entry of Japan into the war would be followed sconer or later by the arrival of submarines in these waters. For this eventuality New Zealand was totally unprepared, except that certain aircraft could carry out anti-submarine patrols of the coast. It was essential that shipping should be given some measure of anti-submarine protection from the time of reaching the focal areas on the inward passage till it sailed laden for overseas. Parry recommended that, on the first indication of a submarine in New Zealand waters, all secondary ports should be closed to overseas ships and the sailings of coastal vessels suspended until their protection was arranged unless heavy losses of these ships could be accepted.
1 SD: Submarine Detector.
Commodore Parry considered that New Zealand was liable to the same scale of attack on shipping as Australia. He therefore recommended that the anti-submarine forces of the Dominion should comprise fast motor anti-submarine boats as a striking force working from defended ports, six at Auckland and six in the Cook Strait area; and six local defence vessels for local convoy and patrol duties, three at Auckland and three in the Cook Strait area. All the existing and projected minesweepers should be fitted with asdics to enable them to work as anti-submarine vessels if necessary and when not minesweeping.
The local defence vessels being built in Australia1 were well suited to New Zealand requirements. If orders were placed now, none would be ready until the end of 1941 at the earliest. It was therefore proposed that the Admiralty be asked to take over the three vessels under construction in the United Kingdom for New Zealand and in return release as soon as possible three of the local defence vessels building in Australia for the Royal Navy.2 Three others should be ordered in Australia for early delivery.
The disadvantages of fast motor-boats were that as asdic-fitted anti-submarine craft they could work in the open sea only in fair weather, they had limited endurance at high speed and poor habitability and could not cover the whole coast. It was roughly estimated that two units of six boats each, with the necessary bases, would involve a capital expenditure of more than £1,000,000 apart from the costs of maintenance. The hulls could be built in New Zealand but the engines, armament, and other equipment would have to be obtained abroad, possibly from the United States.
1 Local defence vessels; 840 tons displacement; twin-screw, oil-burning; speed about 16 knots; one 4-inch gun and one 12-pounder; 25 depth-charges; complement, 4 officers and 58 ratings; cost, approximately £250,000 each.
2 When this suggestion was made to the Admiralty in November 1940, the High Commissioner was informed that the Australian-built vessels were needed urgently for service in the Middle East and could not be spared for New Zealand. The matter would be reconsidered if, in April 1941, the situation became acute.
The training of SD ratings and anti-submarine courses for officers could be undertaken in Australia. If an anti-submarine attack teacher were obtained from England, it would be possible to train officers in New Zealand. A staff officer at Navy Office, Wellington, would be in general charge of anti-submarine matters, the Admiralty to be asked to have an RNZNVR officer now in England trained for that purpose. In the meantime, the Australian Naval Board had agreed that Commander H. M. Newcomb, RN, Officer-in-Charge of the Anti-Submarine School at Sydney, should come to New Zealand to give advice on anti-submarine policy.
Approval in principle to these proposals was given on 16 October 1940 by War Cabinet, which also authorised the procurement of twelve asdic sets, at a cost of approximately £18,000, to be fitted in the auxiliary anti-submarine vessels.
The Admiralty selected Lieutenant-Commander J. A. Smyth, RNZNVR,1 to undergo a long anti-submarine specialist course in HMS Nimrod. He qualified in February 1941, arrived in New Zealand in May 1941, and assumed duty as Staff Officer (Anti-Submarine).
The proposals were referred to the Admiralty, which replied on 1 December 1940 that the best means of defence in New Zealand waters against submarine attack were considered to be (a) convoy escort by ships of the corvette or trawler type and adequate air reconnaissance, and (b) local defence vessels of the trawler type to patrol the approaches to the four main ports. Experience in Home waters suggested six for Auckland, five each for Wellington and Lyttelton, and three for Dunedin. It would be most economical if both the escorts and the local defence vessels were dual purpose A/S M/S ships. It was not thought that a striking force of fast anti-submarine motor-boats would be of value. It seemed very unlikely that Japanese submarines would carry mines as far as New Zealand, where the principal mining danger appeared to be an occasional surface raider. The Admiralty agreed that, in view of the anticipated scale of attack and the navigational difficulties, elaborate and costly fixed anti-submarine defences for New Zealand ports were unnecessary.
In a later message the Admiralty said that if it was desired to proceed with motor-boats for anti-submarine work it was thought the Fairmile type was the most suitable. Supplies of engines, which were manufactured in the United States, and of equipment could not, however, be made before the second half of 1941.
1 Commander J. A. Smyth, VRD, RNZNVR; born NZ 13 Mar 1908; sales manager; joined RNVR (NZ) as Ordinary Seaman, Oct 1928; Lieutenant, May 1932; commanded HM Minesweeper Chestnut, 1940–41.
Four weeks later the High Commissioner informed the Prime Minister that the Admiralty needed a flotilla of fast minesweepers in Malaya and, as the Australian-built ships were better suited for that purpose, it preferred that New Zealand should have the three vessels building at Leith. A number of Admiralty-designed trawlers somewhat similar to them were being built and as soon as four could be spared they would be made available to New Zealand, say about October 1941.1 This offer was accepted by the Government on 5 July 1941.
Taking account of the report of Commander Newcomb on his expert study of the anti-submarine needs of the four main ports, Commodore Parry, on 27 March 1941, recommended for the underwater defences of Auckland an indicator loop system2 to cover the area through which shipping passed on entering and leaving Auckland and a minefield to obstruct the remaining approach. The initial cost of the Auckland proposals was estimated at £160,000 and annual recurring costs at £10,000. No loop system or mining was recommended for Wellington or Lyttelton.
2 The indicator loop consists of a length of cable laid on the seabed, its ends being connected on shore to an instrument designed to record a minute current. A submarine, like all steel vessels, has magnetic properties and when crossing the loop sets up a current which is detected by the shore recorder. This is known as ‘obtaining a signature’.
These proposals were approved by War Cabinet on 4 April 1941. On the same day Commodore Parry had addressed yet another comprehensive paper to the Minister of Defence in which he dealt with the general principles of submarine detection and destruction and summarised his anti-submarine proposals. Immediate steps were taken at this eleventh hour to implement this policy; but it was apparent that months must elapse before it could be brought into operation.
Nine months earlier the Australian naval authorities had informed the New Zealand Naval Board that a factory with a capacity of 1000 mines a year on one shift had begun production. An order for 300 mines could be accepted but delivery would be dependent upon their own and Admiralty requirements. HMAS Bungaree,1 the only minelayer Australia possessed, could probably be spared to lay the mines, but it was unlikely she could make more than one trip to New Zealand.
On 7 April 1941 the New Zealand Naval Board made a signal to the Australian Commonwealth Naval Board requesting the manufacture of 300 mines. A reply was received on 28 June that the order could ‘probably be met any time after 1 January 1942.’ In the course of correspondence about the delivery of the mines, the establishment of a depot and the use of the minelayer, the Naval Board said it was not intended to lay the mines ‘until after the outbreak of a Far Eastern War.’2
When the plans and estimates for the construction of a mine depot at Kauri Point on the north shore of Auckland harbour were produced by the Public Works Department in October 1941, they exceeded the estimate of cost already approved by more than £7000, mainly because it had been found necessary to carve 26 chains of roadway along the steep hillsides to give access to the depot. The additional expenditure was approved in War Cabinet on 21 November 1941 – less than three weeks before Pearl Harbour. In the meantime, Lieutenant Haynes, OBE, RN (retd), Armament Supply Officer at Kauri Point, had been appointed Inspector of Naval Ordnance and Officer-in-Charge of the embryonic mine depot.3
1 HMAS Bungaree, a converted merchant cargo vessel of 3043 tons gross register, built at Dundee in 1937 for the Adelaide Steamship Company Limited.
3 Lieutenant H. A. Haynes, OBE, RN (retd); born England, Mar 1883; Commissioned Gunner, HMS Diomede 1925–27; retired Nov 1927 as Lieutenant.
It had been decided, in the event of war with Japan, that trans-Tasman shipping was to be sailed in convoy. However, owing to more urgent demands on the all-too-few cruisers available for escort duties, this arrangement was short-lived and only two such convoys appear to have been sailed. Anti-submarine escort for them in New Zealand waters was provided by the anti-submarine minesweepers Rata and Muritai.
They sailed from Wellington on 6 January 1942 to meet the first convoy of eight ships which had left Sydney on the 3rd escorted by HMAS Adelaide.1 The Muritai was delayed on passage to assist the Lyttelton floating crane Rapaki which was in difficulties in heavy weather off Stephens Island,2 but she and the Rata took station on the convoy to the westward of Farewell Spit, Wellington being reached on 10 January.
Two days later the Rata and Muritai sailed with a convoy of four ships bound to Sydney. A strong north-west gale was blowing in Cook Strait, and by the time the convoy was off Stephens Island the Rata was two miles and the Muritai six miles astern. They were then ordered by HMAS Adelaide to return to Wellington. On 15 January the Rata and Muritai gave anti-submarine escort to the United States transport Republic, 17,886 tons, from Wellington to a position nine miles south-east from Cape Palliser.
Both ships went to Suva later in the month and the Gale returned to New Zealand for a refit and the installation of asdic. HMNZS Moa arrived at Suva from the United Kingdom on 4 February 1942 and took the place of the Rata, which returned to Wellington. The Matai, followed by the danlayers Kaiwaka and Coastguard, joined company with the Moa and Muritai at Suva during March.
2 The Rapaki, which had been requisitioned on behalf of the British Ministry of War Transport, was on her way to Suez via Australia. She put back to Wellington and thence to Lyttelton, but later was used to handle heavy lifts in American transports at Wellington. At the beginning of 1943 she was sent to Noumea for a similar purpose and returned to New Zealand in November 1945.
The Moa was commissioned on 12 August 1941 by Lieutenant-Commander Connolly, DSC, RNZNVR,2 and sailed from Greenock on 1 November as an additional escort for a North Atlantic convoy. She arrived at Suva on 4 February 1942 and remained there on patrol duty until 6 April, when she sailed for Auckland, arriving there four days later. The Kiwi was commissioned on 20 October 1941 by Lieutenant-Commander Bridson, DSO, DSC, RNZNVR.3 She left Greenock on New Year's Day in company with a convoy for St. Johns, Newfoundland, and arrived at Auckland on 21 May 1942.
1 Kiwi, Moa, Tui, corvette type, 600 tons displacement; one 4-inch gun; five light anti-aircraft guns; depth-charges; triple-expansion engines; oil-fired boilers; speed 13 knots.
2 Commander P. G. Connolly, DSC, VRD, RNZNVR, m.i.d.; born Dunedin, 14 Nov 1899; engineer; commanding officer HMS Deodar (Channel convoys) 1940–41; HMNZS Moa 1941–43; MP for Dunedin Central.
3 Commander Gordon Bridson, DSO, DSC, VRD, RNZNVR, US Navy Cross; born Auckland, 2 Dec 1909; merchant; commanded HMS Walnut (Channel convoys) 1940–41; HMNZS Kiwi 1941–44; NOC Dunedin, 1944; NOC Lyttelton, 1944–46.
4 Scottish Isles class; 140 built during the war; 560 tons; coal-burning boilers; triple-expansion engines; speed 10 knots; armament one 12-pounder gun and five light AA guns; depth-charges.
5 Lieutenant-Commander H. A. Dunnet, VRD, RNR; born NZ 8 Jan 1907; master mariner; commanded HMNZS Inchkeith 1941–43; Sanda 1944; Kiwi 1945–46.
7 Captain P. Phipps, DSC and bar, VRD, RNZN, m.i.d., US Navy Cross; born Milton, 7 Jun 1909; bank clerk; RNZNVR 1928–46; commanded HMS Bay (Channel convoys) 1940–41; HMNZS Scarba 1941–42; Moa 1943; Matai and Arabis (SO 25 M/S Flotilla) 1944–45; transferred RNZN Feb 1946; CO HMNZS Philomel, 1946; executive officer HMNZS Bellona, 1948; CO HMNZS Tamaki, 1949–50; naval assistant, Second Nava Member, 1950–53; Captain, 30 Jun 1952.
All five ships sailed from Greenock on 15 March 1942 as escorts for an Atlantic convoy (ONS 76) and after calling at St. Johns, Newfoundland, arrived at Bermuda on 8 April. During a stay of twelve days repairs were made to the Inchkeith and Killegray, which had been damaged in collisions. The flotilla spent four days at Kingston, Jamaica, and a week in the Panama Canal Zone and arrived at San Pedro, California, on 26 May 1942. With the addition of two American patrol vessels, the New Zealand flotilla formed an anti-submarine escort for a convoy of ten US Navy tankers from San Pedro to Pearl Harbour, where they arrived on 22 June.
With the exception of the Killegray, which was detained for major repairs to her boiler, the flotilla sailed on 6 July for Palmyra Island, whence it escorted the United States transport Majaba to Fanning Island and Suva. On passage from Suva the Sanda and Scarba ran short of coal about 300 miles from New Zealand and were taken in tow by the Tui and Inchkeith, the flotilla arriving at Auckland on 4 August. As very little coal was available at Pearl Harbour, the Killegray left that port for Suva on 29 August in tow of the Dutch motor-vessel Japara and finally arrived at Auckland on 16 September.
Drawings and specifications of the Fairmile anti-submarine motorboat2 developed by the Fairmile Marine Company were received from England in April 1941. After discussions between the Ship-building and Repairs Committee and Auckland boat-building firms, it was agreed that these craft could be built in New Zealand, the engines and other equipment and prefabricated parts being ordered from England. On 17 December 1941 War Cabinet approved the recommendation of the Supply Council that twelve Fairmile motorboats should be built, and the orders were distributed among four Auckland firms. The estimated cost of each vessel was £35,000, making a total of £420,000 for the twelve.
1 Captain J. G. Hilliard, DSC, VRD, RNZNVR, m.i.d.; born Auckland, 15 Jan 1908; company director; CO HMS Blackthorn (Channel convoys) 1940–41; Tui 1941–44; executive officer Philomel, 1944–45; CO Auckland Division RNZNVR, 1946; Captain, 31 Dec 1951.
2 Fairmile motor-boat; length, 112 ft; breadth, 17 ft 10 in; mean draught, 4 ft 10 in; 80 tons; two Hall-Scott 12-cylinder petrol engines, each of 630 horse-power; speed, 18 ½ knots.
When Japan entered the war in December 1941 there were no fixed underwater defences against submarines in any New Zealand harbour. At the beginning of 1941 War Cabinet had approved the construction of an anti-boat boom across the channel into Auckland harbour at an estimated cost of £30,000. The possibility of providing steel-wire nets as a counter to enemy small craft was examined, but it was thought that it would be difficult to obtain the wire to make the nets. Because of the danger of attack by midget submarines such as the Japanese had employed at Pearl Harbour, it was decided that the hardwood piles in the boom should be spaced not more than five feet apart. The estimated additional cost of £15,000 was approved in War Cabinet on 30 December 1941.
Meanwhile arrangements were being made to lay the anti-submarine indicator loops authorised in April 1941 across the Hauraki Gulf channels. The small steamer Kaitoa1 was selected for the purpose, but later was found to be unsuitable for conversion. The Australian naval authorities then agreed to make their cable-laying vessel Mernoo2 available and it was decided to charter her. The Mernoo arrived at Auckland on 27 February 1942, completed the laying of the indicator loops on 29 March, and sailed two days later on her return to Melbourne.
At the end of December 1941 the Naval Board had considered plans for an anti-boat boom of piles and an anti-torpedo net across the outer harbour at Wellington at an estimated cost of £285,000. The time required to carry out the work was stated to be two years. The Board was disturbed by the estimate of cost and the difficulty of getting supplies of steel wire for the net and, on 19 January 1942, it informed the Minister of Defence that it was intended to construct only the eastern section of the piled boom. War Cabinet approved the proposed expenditure on this project on 19 March 1942.
The New Zealand Naval Board's proposals for Auckland included an anti-torpedo net boom complete with gate and gate vessel to close the gap of 700 yards in the anti-boat piled obstruction then under construction, as well as additional indicator loops in the outer channels. Other underwater defences would be the independent and controlled minefields already planned as part of the anti-invasion measures.
The United States Navy Department agreed to supply an anti-torpedo net boom with gate and gate vessel to cover the full width of the approach channel to the inner harbour. It asked that the scheme for a fleet anchorage inside a line from Tiri Tiri to Rangitoto be completed to the extent necessary to give underwater protection to ships so anchored, and that the proposed mine defences at the Bay of Islands and Great Barrier Island be installed to enable those anchorages to be used. The United States Navy Department also indicated that it was proposed to use the Wellington area for the training of an amphibious division of Marines. Underwater defences would be needed in Wellington harbour and Queen Charlotte Sound for the protection of an estimated maximum of twelve transports and twenty other large vessels.
At the direction of the Chief of Naval Staff a comprehensive scheme for strengthening the naval defences of Wellington was prepared. This comprised anti-submarine fixed defences in the main channel, an extension of the anti-boat piled boom to cover the western side of the outer harbour, a net boom with gate and gate vessel, anti-torpedo nets to protect the floating dock and Aotea Quay, anti-torpedo baffles to guard the other wharves, as well as the shore stations for the officers and men to operate the defences. The erection of a radar station at the harbour entrance was also recommended. This scheme, estimated to cost £652,500 in capital charges and £11,050 a year for wages, was approved in War Cabinet on 25 April 1942.
1 comanzac: United States Commander of Anzac Area and Forces.
Much of the material and equipment for the net booms at Auckland and Wellington was supplied by the United States Navy Department on a lease-lend basis. The preparation and installation of the booms were carried out under the superintendence of Commander H. M. Montague, OBE, RN, Staff Officer (Boom Defence).
For various reasons, including the shortage of manpower and material, there were delays in the construction of the boom depots at Auckland and Wellington. Thus, when an American naval party under Lieutenant-Commander J. A. Rylander, USNR, started on 20 July 1942 to rig the anti-torpedo boom at Auckland, Commander Montague was moved to protest that ‘while it is gratifying that the actual work should have been started, the feeble share borne hitherto by the R.N.Z. Naval Service is deplorable … I would urge that all possible steps be taken to hasten the construction of the boom depots and the provision of boats, vessels and men so that we can take a worthy share in furnishing our own defence instead of sitting back and letting the Americans labour alone and unaided.’2
The Auckland net boom and anti-torpedo baffles were completed about the end of September 1942. No other vessel being available, the United States net tender Ebony,3 which had laid the nets, was used as the gate opening vessel until she was called away early in January 1943 for duty at Noumea. In the meantime the aged steamer Claymore was being repaired and fitted out as a gate vessel at a cost of more than £10,000. It was decided that the gate would have to remain open until she was ready, a tug or launch being used to close it in an emergency. The Napier dredge Whakarire was hired in April 1943 and also fitted out as a gate vessel. It was not until October 1943 that the Claymore and Whakarire were commissioned and commenced duty at the main gate of the boom.
1 Commander C. C. Lowry, RN, m.i.d.; entered RN, 1926; joined survey service, 1934; commanded HMNZS Lachlan 1952–54.
2 Minute of Staff Officer (Boom Defence) to Naval Board, 23 July 1942. Actually, the estimates for the Auckland boom depot were not submitted to the Government till 19 July. They were approved in War Cabinet three days later and those for the Wellington depot in August.
3 Ebony, boom defence net tender; 700 tons displacement; diesel-electric propulsion; speed 14 knots; one 3-inch AA gun.
With the approval of War Cabinet, the lighters Matata and Matuku for Wellington and Ruru and Titi for Queen Charlotte Sound were requisitioned from the Gisborne Lightering and Stevedoring Company after a cursory inspection. They were towed to Wellington, where, four months later, a survey revealed that they were ‘full of decay’ and had other serious defects, making them quite unfit for service as gate vessels. It was ultimately decided to return them to their owners.1 The minesweeping trawler Futurist was converted into a gate vessel but it was October 1943 before she was commissioned for that service.
The auxiliary scow Vesper2 was chartered from her Auckland owners to lay the cables for the additional anti-submarine fixed defences at Auckland and those at Wellington and Queen Charlotte Sound. In addition to the indicator loops, two harbour defence asdics were laid at Wellington and four at Auckland. The American loop equipment installed at Wellington was replaced subsequently by instruments of Admiralty pattern. Owing to delay in completing the control and power rooms, the Wellington station did not go into full operation until the end of April 1943. The Auckland stations at Takapuna and Motutapu were commissioned in November 1943.
Sixteen harbour defence motor-launches purchased in the United States were commissioned between March 1943 and March 1944 and operated as the 124th and 125th Motor Launch Flotillas, based on Auckland and Wellington respectively. They were equipped with depth-charges and maintained anti-submarine patrols inside the indicator loops. Though they were not tested by enemy action at any time, the anti-submarine fixed defences at Wellington and Auckland attained a high degree of efficiency.
1 When the Matuku and Ruru were being towed to Gisborne in August 1943 they broke adrift from the tug and the former drifted ashore and became a total loss. The Ruru was picked up and towed first to Napier and thence to Gisborne, where the owners refused to accept delivery. The Titi broke adrift from her moorings in Wellington harbour in September 1943 and went aground at Kaiwarra. She was refloated but, being water-logged, could not be slipped for repairs and was beached in Evans Bay. The owners claimed £9723 but, after lengthy negotiations with the Treasury, agreed to accept £8250 for the four lighters. This was approved in War Cabinet on 24 December 1943. The Auditor-General in his annual report drew attention to the ‘very unsatisfactory nature of this transaction’ and said the matter should have been referred to a magistrate for settlement. In a report to the Minister of Finance, Treasury said that Navy Office appeared to have been negligent in not ascertaining the true condition of the lighters before they were requisitioned and dilatory in their subsequent decisions and actions. Navy Office held that responsibility for requisitioning the vessels after a survey at Gisborne had revealed their poor condition rested with the Marine Department. The Matata was sold in November 1944 for £250.
Work on the underwater defences in Queen Charlotte Sound had barely started in the latter part of 1942 when comsopac indicated that, because of the changed situation in the Pacific, it was unlikely that the sound would be used as a fleet anchorage. Accordingly, with the approval of War Cabinet, the scheme was drastically modified. Work on the boom defence project was stopped and the proposed minefields were cancelled. The indicator loops of the anti-submarine fixed defences were laid in the main entrance to the sound and the control station built, but the instruments were not installed. These and other works had been completed when, in November 1943, with the concurrence of comsopac, it was decided not to proceed any further with the Queen Charlotte Sound defences on which about £96,000 had been spent. The question of charging the cost of the works, less any residual value, to the United States authorities on a reverse lease-lend or cash basis was left to the Treasury.
The underwater defences planned for Lyttelton were an anti-torpedo net boom to protect the inner harbour, a controlled minefield in the main entrance, and a series of indicator loops and harbour defence asdics to cover the seaward approaches to the port. In June 1942 these proposals were submitted to comsopac, who referred them to Washington. The United States Navy Department, however, was reluctant to provide the considerable quantity of loop material needed. The anti-submarine fixed defences, as well as the controlled minefield, were cancelled but, following the approval of War Cabinet in January 1943, the anti-torpedo boom was rigged to cover the entrance to the inner harbour. This was worked from shore stations and came into operation on 28 May 1943. In less than six months, however, it ceased working and the boom remained open till July 1944, when it was dismantled.
The first officers and ratings for anti-submarine duties, twelve in all, were trained in HMAS Rushcutter at Sydney. Subsequently, instruction was started at an improvised school at Auckland, but no-material was then available for demonstration. In September 1942 an anti-submarine training establishment, known as the Naval Electrical School to disguise its activities, was opened on the foreshore at Petone, Lieutenant Berry, RNZNVR, being appointed as Officer-in-Charge.1 This was the principal anti-submarine school and provided continuous training for about ten officers and forty ratings. The school had an attack teacher, asdic sets for demonstration purposes, procedure teachers, a cinema, loop instruction and echo-sounding equipment. A small training establishment with attack teacher and working-up organisation was maintained at Auckland.
Most of the RNZN watchkeeping officers and some hundreds of ratings passed through the anti-submarine school at Petone. A high degree of efficiency was maintained by the anti-submarine vessels of the Royal New Zealand Navy, most of which operated under the orders of comsopac in the South Pacific, where they achieved the destruction of one Japanese submarine and took part in the sinking of another.
Authority for the formation of a Naval Auxiliary Patrol Service was given by War Cabinet on 6 December 1941. The objects of the service were to assist in the protection of harbours against enemy attack, particularly by small craft, the spotting of mines dropped by parachutes, and the saving of life. The NAPS was constituted under the Naval Defence Emergency Regulations 1941 and was deemed a part of the Royal New Zealand Navy. Enlistment was open to men over the age of 16 years, but it was expressly provided that such enlistment did not absolve any person from liability for service with any of His Majesty's armed forces or from any liability to which he might be subject under the National Service Emergency Regulations 1940.
The motor-boats employed in the service were the property of the owner-members of the NAPS. Owner-masters were entered as chief petty officers and deputy skippers as petty officers. They and their crews were given a modified naval uniform. Service was honorary, but if called up for fulltime service members were to receive pay and allowances. Fuel and other stores were provided by the naval authorities for use on duty.
The Naval Auxiliary Patrol Service, which was, in effect, a naval Home Guard organisation, operated under the orders of the naval officers in charge of the four main districts. The duty boats patrolled their respective harbours from sunset to sunrise daily, those at moorings being held in readiness for instant service in the event of an emergency. Instruction was given in signalling, chart work, coastal navigation, etc. Members of the NAPS showed keen interest and carried out their duties efficiently. The strength of the NAPS varied from time to time, due to men being called up for active service. Total entries were approximately 570, made up as follows: Auckland 180, Whangarei 84, Wellington 140, Lyttelton 68, and Dunedin 98. The service was disbanded early in 1944.
It was fortunate for the Allies' war effort in general and that in the Pacific in particular, that Japanese doctrine regarding the employment of submarines differed fundamentally from that of the Germans. From the outbreak of war in 1939 the German naval effort, expressed more and more in submarines, was directed against British and Allied merchant shipping and sea communications with page 211 dire effect. In the first six months of 1942 the sinkings averaged three a day and totalled 546 vessels of 2,964,000 tons. But the Japanese submarines' share in that grim harvest was only seven ships of 31,456 tons.
At the time of Pearl Harbour the Japanese Navy possessed 60 fully operational submarines, 46 of which were of the I class and 14 of the Ro class. The former ranged from about 1500 tons to 2600 tons displacement and had a speed of from 18 to nearly 24 knots. They had a cruising range at economical speed of up to 16,000 miles. The I class submarines had from six to eight 21-inch torpedo-tubes, carried up to twenty-two torpedoes, and mounted one or two 5·5-inch or 4·7-inch guns and several light anti-aircraft guns. Many of them had a built-in hangar housing a small seaplane for reconnaissance purposes. At least five were fitted to carry a midget submarine, which was secured on deck by chocks and steel bands and four lugs with quick-release bolts. The Ro type of submarine ranged from 600 to 1000 tons, with a speed of from 16 to 19 knots, and had from four to six 21-inch torpedo tubes.
The submarines were employed primarily in fleet operations. Thus, ten to twelve I class boats, designated the Advance Expeditionary Force, took part in the attack on Pearl Harbour. Three proceeded ahead of the main task force on scouting and reconnaissance duties. Five of the others carried midget submarines which were to enter Pearl Harbour after the air attack. None of the midgets survived; one of the I class boats was sunk and another damaged. Submarines scouted for the Japanese forces engaged in the battles of the Coral Sea and Midway. They also took an active part in the naval operations in the Solomon Islands, where they sank or damaged a number of American aircraft-carriers and other warships. In addition to fleet operations, Japanese submarines were constantly employed on long-distance reconnaissance missions which took them as far afield as the west coast of the United States, the Indian Ocean and, on two known occasions, to the shores of New Zealand.
The months following Pearl Harbour afforded a remarkable contrast between Japanese and German submarine methods. When the United States was forced into war, an entirely new sphere of operations became wide open to German U-boats in the Western Atlantic which previously had been barred to them for political reasons. They left the convoy routes and concentrated against the unescorted and unarmed merchant shipping in American coastal waters, where they found a rich choice of easy targets and sinkings rose alarmingly. During May 1942, 95 per cent of all U-boat sinkings of ships were in American waters. During the critical months that followed Japanese submarines made not the slightest effort to check the page 212 rapidly increasing flow of shipping as the Americans built up their island bases and lines of communication across the Pacific and made ready to strike back at the enemy from New Zealand and Australia. The refrigerated cargo ships with their precious freights of vital foodstuffs from New Zealand, as well as many from Australia, had already suffered severe losses from German U-boats in the Atlantic, but they sailed unscathed across the Pacific to Panama.
At that time New Zealand's anti-submarine defences were in an embryonic stage and the grim happenings on the Atlantic coast showed that the Americans were also ill-prepared. An all-out Japanese submarine onslaught against merchant shipping in the Pacific, co-ordinated with that of the German U-boats in the Atlantic, could have achieved disastrous results. Fortunately, the Japanese made no such effort and by the end of 1942, as the Allied offensive operations in the South Pacific gathered way, they were compelled to use submarines more and more to transport men and supplies in areas in which it was becoming too risky to move surface ships.
Meanwhile, American submarines were ranging far and wide in the Pacific, attacking Japanese convoys and sinking ships wherever they could be found. From December 1941 to August 1945 they accounted for 1113 enemy ships totalling 4,780,000 tons,1 approximately 64 per cent of all Japanese shipping tonnage sunk in the Pacific, and more than 80 per cent of the total merchant ship tonnage registered in Japan in 1940–41. They also sank 201 Japanese naval vessels, including 23 Japanese submarines. The achievements of United States submarines afford some measure of Japan's failure in the strategic use of her submarines.2
The first venture of a Japanese submarine into New Zealand waters appears to have been made in March 1942; but possibly one or more may have done so even earlier. Almost the only firm evidence of the presence of enemy submarines off the coast of New Zealand comes from a Japanese document, captured in 1944, which records the reconnaissance cruises made by aircraft-carrying submarines between 30 November 1941 and 11 November 1942. This document revealed that during that period ten I class submarines of the Sixth Fleet made lengthy cruises extending to the west coast of the United States and Zanzibar, on the east coast of Africa, as well as to the South Pacific.
1 Japanese Navy and Merchant Shipping Losses during World War II; compiled by the Joint US Army–Navy Assessment Committee, February 1947.
2 Assuming that roughly one half the merchant ships lost in the Indian Ocean were sunk by Japanese submarines and half by German U-boats, and crediting the former with the sinkings in the Pacific, the Naval Staff (Trade Division) of the Admiralty calculated that on this basis, from December 1941 to May 1945, Japanese submarines sank altogether about 145 merchant ships and German U-boats (in all areas) 1650 vessels. The effective scale of activity by Japanese submarines against merchant shipping was, therefore, only about one-twelfth that of the Germans and about one-eighth that of the Americans against Japanese shipping.
The submarine I-10 was in Fijian waters at least eight days before the attack on Pearl Harbour. Her seaplane made a night reconnaissance over Suva harbour and its approaches on 30 November 1941. Both the Achilles and the Leander were in the Fiji area at that time. The former had escorted the Wahine carrying troops from Auckland to Lautoka and the Leander was ‘trailing’ the American liner Mariposa to Auckland. Dawn patrols over Suva and Lautoka were carried out by RNZAF aircraft, but neither they nor the ships sighted anything suspicious.
It was in this area seven weeks later that the Royal New Zealand Navy had its first encounter with a Japanese submarine. In the afternoon of 16 January 1942, HMNZS Monowai had just cleared Suva harbour when, following two heavy explosions, a submarine was page 214 seen breaking surface about 7500 yards away. After a brief exchange of gunfire in which no hits were made by either side, the submarine broke off the action and crash-dived.1
Two New Zealand traders had escapes from Japanese submarines at the beginning of March 1942. The Union Company's Narbada was shelled by an I-boat about 100 miles north-west from Fremantle in the afternoon of 2 March. The steamer was hit by shell splinters, but when she opened fire the submarine ceased its attack and disappeared. Next day, about 150 miles further south, the New Zealand Shipping Company's Tongariro, on passage from Wellington to Fremantle, was chased by a submarine, which dived when the ship opened fire.
Early in 1942 the submarine I-25 made an extensive cruise which embraced eastern Australia, New Zealand, and Fiji. At that time I-25, commanded by Commander Masaru Obiga, was a unit of the 4th Division of the Sixth Fleet, based at Truk in the Caroline Islands. The submarine came southward through the Coral Sea and made a leisurely cruise down the Australian coast. At daybreak on 7 February 1942 the boat's seaplane made a flight over Sydney harbour. I-25 then proceeded slowly southward to Bass Strait, and nineteen days later its aircraft made a dawn reconnaissance flight over Melbourne and Port Phillip. The approaches to Hobart were reconnoitred next and the aircraft flew over that port in daylight on 1 March.
From Tasmania, I-25 crossed the Tasman Sea to New Zealand and entered Cook Strait, a pre-dawn flight over Wellington being made in the morning of 8 March. Neither the submarine nor its aircraft was reported locally. Doubtful D/F bearings2 of a Japanese unit were obtained at 11 p.m. on 9 March, which when plotted placed it some 400 miles west from North Cape. From Cook Strait I-25 carried on up the east coast of the North Island to the vicinity of Auckland, where the seaplane made a flight, again before dawn, over the Hauraki Gulf and the port.
2 D/F: Radio direction-finding.
According to the Japanese record, the I-25 went north from the Auckland area to the Fiji Islands, where its aircraft made a reconnaissance flight over Suva at dawn on 19 March. On the same day the Kandavu coastwatching station reported that a seaplane was sighted off Suva harbour and an unidentified craft was seen to the eastward of Cape Washington. Later in the day it was reported that the aircraft was seen to come down close to the vessel. Special searches were made by RNZAF aircraft, and an anti-submarine vessel was ordered to carry out extensive coastal patrols. Next day the port war signal station at Suva reported the sighting of a strange craft believed to be a submarine. Aircraft and two anti-submarine vessels carried out extensive searches in the approaches to Suva harbour. One of the aircraft reported a log with an accumulation of seaweed and this was accepted as a possible explanation of the sighting. There can be little doubt, however, that it was I-25 and its aircraft that had been seen. The submarine returned from the Fiji area to its base at Truk. At the beginning of August 1942 the I-25 was off the Pacific coast of the United States.
After the battle of the Coral Sea on 7 May 1942 there was a sudden burst of Japanese submarine activity in eastern Australian waters. Their first victims were an American steamer of 7200 tons sunk on 5 May and the Greek steamer Chloe, 4640 tons, sunk next day, both within a few miles of Noumea, possibly by one of the I-boats scouting for the Japanese forces engaged in the Coral Sea operations. On her arrival at Newcastle from Wellington the Russian steamer Wellen, 5135 tons, reported that on the night of 16 May she was shelled by a submarine about 80 miles north-east from Sydney, sustaining minor casualties and slight damage.
After making a dawn reconnaissance of Suva on 19 May, the submarine I-21 came south to New Zealand and sent her seaplane over Auckland and the Hauraki Gulf five days later. At that time the Achilles was escorting the Rangatira back from Suva, the Monowai was in harbour, and HMAS Adelaide was approaching the port with a convoy from Sydney. There were no reports of either I-21 or its aircraft being sighted, but on 26 May D/F bearings indicated a Japanese submarine in a position about 400 miles west from North Cape. This was probably I-21 on its way to the Australian coast, page 216 where its commanding officer, Commander Hiroshi Imada, became senior officer of the group of five submarines from which a raid on Sydney harbour was made a few days later.
During the night of 29–30 May the seaplane from I-21 reconnoitred Sydney harbour and reported the presence there of ‘battleships and cruisers’,1 and it was decided to attack them with midget submarines the following night. At 4.30 p.m. on 31 May three midgets were released from their parent submarines a few miles north of the entrance to the harbour. About four hours later a watchman sighted an object caught in the anti-submarine net boom inside the heads. It was identified as a small submarine and at 10.15 p.m. it blew itself up. The wreck was subsequently salvaged.
A second midget was sighted just before eleven o'clock by the USS Chicago which was lying off Farm Cove, and she and the Whyalla opened fire on it. The Chicago was about to slip from her buoy when, at 0.30 a.m., two torpedoes were fired at her. Both missed the cruiser, but one exploded under the Kuttabul, a former ferry steamer converted into a depot ship, killing twenty-one ratings and wounding ten others. This midget was attacked and sunk by depth-charges on its way down harbour. The third midget which had got past the net boom2 was sunk by depth-charges in Taylor Bay some hours later and subsequently salvaged.3 Markings on charts recovered from one of the midgets indicated that five I class submarines, numbers 21, 22, 24, 27, and 29, took part in the raid, the midgets being borne by I-22, I-24, and I-27 to the point of release.
Far away in the Indian Ocean on the night of 30 May, a Japanese midget submarine made a successful attack on British ships at Diego Suarez, Madagascar.4 HMS Ramillies was damaged by a torpedo and the tanker British Loyalty, anchored nearby, was torpedoed and sunk. A few days later two Japanese were rounded up north of Diego Suarez and killed by a commando patrol. Papers found on them showed that they were the crew of a midget submarine whose parent ship was I-20.
1 The naval ships in harbour at the time were the cruisers Canberra, Adelaide, and Chicago; armed merchant cruisers Westralia and Kanimbla; US destroyer Perkins; US destroyer tender Dobbin; corvettes Geelong, Whyalla, and Bombay; depot ship Kuttabul, and Netherlands submarine K-9.
2 Only the centre part of this boom was complete. There were gaps of 320 yards at one end and 300 yards at the other end.
3 This midget was 80 ft 6 in in length and its breadth 6 ft. It carried two torpedoes with an explosive head of about 700 lb and had a cruising range of about 18 miles at 20 knots and 175 miles at 5 knots, the single large propeller being driven by an electric motor. The midget, which was fitted with self-demolition charges, had a crew of two men.
4 Diego Suarez had been occupied by a British force on 7 May 1942.
A few days after the Sydney harbour raid, Japanese I-boats attacked merchant shipping off the Australian coast.1 On the night of 3 June 1942 the Broken Hill Proprietary's steamer Iron Chieftain, 4812 tons, was torpedoed and sunk 30 miles east from Sydney. Less than an hour later and about 35 miles further to the north-east, a submarine fired four shells at the steamer Age. Next day the Iron Crown, 3353 tons, loaded with 5500 tons of iron ore, was sunk with heavy loss of life off Cape Howe, on the border of New South Wales and Victoria. An RAAF aircraft which saw the attack bombed the submarine and made two near misses. The steamer Barwon reported a near miss by a torpedo in the same locality, and the Echunga that she had been chased by a submarine about midway between Sydney and Jervis Bay.
An aircraft bombed and claimed to have sunk a submarine on the morning of 5 June about 110 miles south-east from Sydney; and in the afternoon an aircraft narrowly missed another about 180 miles north-east from that port.2 In the early hours of 8 June a submarine fired several shells into a Sydney suburb and Newcastle was shelled an hour and a half later. Next day the Blue Funnel steamer Orestes, 7743 tons, reported being fired at by a submarine southeast of Jervis Bay. The attacks ended for the time being on 11 June when the Panamanian steamer Guatemala, 5967 tons, which had straggled from a convoy, was torpedoed and sunk about 120 miles south-east from Sydney.
Though they might have made reconnoitring cruises other than those already mentioned, Japanese submarines made no attempt to molest shipping in New Zealand waters through which, in addition to the normal commercial traffic, there was from the middle of 1942 onwards a great flow of Allied transports and supply ships.
On 18 June 1942 the Rangatira, making a daylight passage from Lyttelton to Wellington, reported passing in dense fog about 14 miles from Godley Head an object resembling a small submarine. In the afternoon a searching aircraft sighted a log about three miles south of the position given by the Rangatira.
2 Debris and oil were seen after both attacks. The first-mentioned submarine was probably damaged. Neither Japanese records nor Allied post-war assessments list any submarine as being sunk off the Australian coast at that time.
Japanese submarines were again active in Australian waters in July-August 1942. A Greek steamer and two American steamers totalling 15,300 tons were sunk off the New South Wales coast on 20 July. Two days later the Australian steamer Allara, 3379 tons, was torpedoed off Newcastle and towed into port with the loss of four killed and six wounded. The Dutch motor-vessel Tjinegara, 9227 tons, was sunk 90 miles from Noumea on 25 July. During the next few days three vessels reported being shelled by submarines, one as far away as the western end of the Great Australian Bight. A small vessel of 300 tons was sunk south of Port Moresby on 6 August and another of 3300 tons was damaged by a torpedo in the same locality on 29 August.
By that time the Solomon Islands campaign was well under way and the submarines were concentrated in and about that area, where some were employed frequently to transport troops and supplies. In the five months to the end of January 1943, nine Japanese submarines were destroyed in the South Pacific, six of them in the Solomons. One was I-1 which was wrecked on the northern end of Guadalcanal after a fierce action with HMNZ ships Kiwi and Moa on the night of 29–30 January 1943.1
Though no confirmation from Japanese sources has been found, it is certain that a submarine was in New Zealand waters about the end of February 1943, cruising through Cook Strait and up the east coast of the North Island. Shortly after midnight of 22–23 February an unidentified radar contact was made from Cape Taurakirae, south-west headland of Palliser Bay, bearing about south-east by south, distant 10 miles. Ten minutes later a fair D/F ‘fix’ of a submarine was obtained from four stations in the Cook Strait area. Four aircraft from Nelson carried out a parallel track search and one reported sighting a long streak of oil three miles south from Taurakirae.
In the afternoon a battery at the entrance to Pelorus Sound reported sighting a ‘black speck’ about 15 miles off to the northeast. The United States anti-submarine minesweeper Sheldrake was sent from Wellington to search the area. About four hours later Cape Campbell reported a radar contact in a position about 20 miles south from Cape Palliser. Subsequently the submarine was re-placed north of Cook Strait towards the Wanganui area, in which the coastal vessel Storm had reported seeing lights and a partly submerged object in the early hours of 18 February.
Cook Strait and its approaches were searched intensively for three days and anti-submarine escort was provided for a United States task force which arrived at Wellington from Guadalcanal on 25 February. By that time, however, the submarine had left Cook Strait and was well up the east coast of the North Island. On the night of the 25th it was located by D/F 50 miles south-east from Mahia Peninsula. Aircraft carried out a search next morning and one reported a radar contact which was held for forty minutes off East Cape, but nothing was sighted. Air patrols from East Cape towards Great Barrier Island were carried out during the next two days. The submarine had left the coast and in the early hours of 1 March it was located by D/F about 300 miles north-north-east from North Cape.
Because of the suspected presence of a submarine in Pegasus Bay on 25 February, anti-submarine escort was provided for the interisland steamer. A searching aircraft saw nothing, but a whale was sighted from Godley Head at daybreak next morning.
During the next four months Japanese submarines sank thirteen merchant ships totalling 78,369 tons in the South Pacific, eight of them off the east coast of Australia. One of the latter was the Union Steam Ship Company's motor vessel Limerick, 8724 tons, page 220 which was torpedoed in convoy off Sandy Cape, Queensland, on 25 April 1943, two lives being lost. Another was the Australian hospital ship Centaur, 3222 tons, sunk with heavy loss of life 50 miles from Moreton Bay on 14 May. Of the other five ships lost, three were American steamers sunk in the Fiji area, one near Noumea, and one north-west of Tongatabu. Among other vessels attacked up to the end of August 1943 were an Australian passenger ship and an American tank landing ship off the New South Wales coast; two tankers and two liberty ships in the New Hebrides-Fiji area were torpedoed but were able to make port.
There were a few unconfirmed indications of submarines in New Zealand waters during the latter part of 1943. On 6 September HDML 11861 made an asdic contact while on patrol off Cape Brett and dropped depth-charges, but a search revealed no sign of any submarine. The United States submarine Raton reported on 11 October that two torpedoes had been fired at her in a position about 300 miles north-east from Auckland.
In the evening of 3 November Cape Campbell reported a series of radar contacts and the sighting of a low-lying object bearing about south-east. The inter-island steamers were warned to keep five miles outside their normal tracks and to zigzag in the vicinity of Cape Campbell. About two hours after the third radar contact was reported the motor-launches 400, 402, and 405 were ordered out from Wellington harbour to make anti-submarine searches. Motor-launch 409 continued her routine patrol outside the heads and the minesweepers Awatere and Maimai left port shortly after midnight to maintain an anti-submarine patrol between Baring Head and Karori Rock. At 4.19 a.m. ML400 sighted an object about due east of Cape Campbell and she and ML405 dropped depth-charges. Nothing further was sighted and the launches then screened the steamer Maori on her passage across Cook Strait.
On 12 November 1943 the United States transport Cape St. Juan, 6710 tons, was torpedoed and sunk about 160 miles west-south-west from Tongatabu. There was some loss of life, but 1180 survivors were rescued. An RNZAF aircraft flying to Norfolk Island on 27 November reported sighting a submarine periscope about 100 miles north from North Cape, and on the following day another aircraft reported a radar contact east of the North Auckland peninsula.
1 HDML: Harbour defence motor-launch.
The inter-island passenger services were suspended for the time being and Wellington and all ports on the east coast of the South Island were closed to outward shipping while anti-submarine vessels and aircraft carried out searching patrols. In the afternoon of 1 March an aircraft reported sighting well off shore east of Kaikoura what resembled a submarine barely submerged. Stormy weather interrupted the search for two or three days, but on 8 March one of the anti-submarine trawlers made an asdic contact on a possible submarine about 11 miles south from Pencarrow Head. A pattern of depth-charges was dropped and an air search was also made. An hour or two earlier the Wakakura sighted what looked like a periscope 40 miles north-east from Lyttelton Heads and made a depth-charge attack.
For the remainder of the year 1944 Japanese submarine activity in the South Pacific was very slight. None was evident in New Zealand waters and but few submarines were reported off the east coast of Australia. For the most part they appeared to be employed in evacuating key personnel from and carrying supplies to Japanese forces isolated in the Solomon Islands and New Britain, on the northern coast of New Guinea, and in island bases bypassed by the American forces in the Central Pacific. ‘Japanese submarines are offering virtually no resistance to the vast tonnage of American shipping plying in the Pacific,’ said Mr Elmer Davis, United States Director of War Information, in August 1944. ‘One of the war's greatest mysteries is the ineffectiveness of Japanese submarines.’ Fifty-seven of them were sunk during 1944.
Japan began her war with sixty submarines and during the period of hostilities built 127 of the I and Ro classes, as well as numerous midgets; in addition, she took over eight German U-boats. The Allied assessments, which are confirmed by Japanese naval records, show that 130 of her submarines were sunk and four were scrapped, leaving fifty-three in being in August 1945, as well as the eight ex-German U-boats.page 222
The final venture of a submarine (possibly German) into the Tasman Sea appears to have been made about the end of 1944. On 24 December of that year the American steamer Robert J. Walker, 7180 tons, was torpedoed and sunk about 200 miles south-east of Jervis Bay, New South Wales.