In 1942 the RNZN became engaged in its major operational commitment during World War Two. From mid 1942 until the end of the war, 22 ships and vessels and thousands of officers and sailors participated in the Solomon Islands campaign.
The Solomon Islands are strategically placed in the South West Pacific, roughly to the east of New Guinea, north of New Caledonia and north west of Fiji, with Vanuatu between the latter two. This location made the Solomons, particularly Guadalcanal, well placed to support Japanese operations against these islands and north-eastern Australia as well as the shipping route from there to the United States.
The Japanese moved into the Solomons in March 1942. By July they had established a presence on the northern end of Guadalcanal where they were constructing a large airfield at Lunga, opposite the small island of Tulagi, near present day Honiara. While the battles of Coral Sea and Midway forced the Japanese to cancel plans to take New Caledonia, Fiji and Samoa, the new airfield remained important to support operations in New Guinea and the South West Pacific sea-lanes.
Independently, the American Chiefs of Staff were developing plans to occupy the Solomons, expel the Japanese from New Guinea and retake the occupied islands in the Bismark Archipelago to the north. Code-named Operation Watchtower, this campaign was planned to commence on 1 August 1942, but was deferred until the 7th.
HMNZS Monowai, an Armed Merchant Cruiser, made the RNZN's first specific contribution to the campaign in late July, when she transported some US marines who had been training in New Caledonia to Fiji to join the amphibious ships. After practice landings in Fiji, the Marines landed unopposed on Guadalcanal on the morning of 7 August and by nightfall about 11,000 men were ashore. The Japanese reacted swiftly. Bombers from Rabaul attacked during the day and a strong Japanese Naval force entered the area that night.
Then the battle for the Solomons began in earnest. In the Battle of Savo Island on the night of 8-9 August, a Japanese cruiser force sank three United States cruisers and the Australian cruiser HMAS Canberra; they disabled a fourth American cruiser, receiving only light damage to two cruisers in return. Thereafter there were almost nightly battles between the United States ships and the 'Tokyo Express', Japanese warships transporting men and supplies down the channel between the islands, which became known as 'The Slot'. In the ensuing months the battle ground between the two opponents off Guadalcanal saw so many ships lost that it was renamed 'Iron Bottom Sound'.
HMNZ Ships Achilles, Leander and Monowai were retained with several destroyers in a separate task group employed on convoy escort duties outside the operational theatre. However by September, American losses in cruisers were such that they became actively employed in operations to the beachhead. On 5 January 1943 Achilles was patrolling off Guadalcanal as part of a United States Navy Task Force TF67, when four Japanese aircraft attacked. One bomb hit her on a gun turret, resulting in 13 killed and eight seriously wounded. She subsequently went to England for a long refit, not recommissioning until May 1944.
In December 1942, the four ships of the 25th Minesweeping Flotilla, comprising the three 'Bird class' corvettes HMNZ Ships Kiwi, Tui and Moa, with HMNZS Matai as senior ship, had deployed to the Solomons. During the night of 29-30 January 1943, Kiwi and Moa, on patrol off Guadalcanal, fought a successful action against the large Japanese submarine I-1. Forced to surface after being depth charged, the submarine was engaged by gunfire from the two small ships. In a fierce action that lasted more than an hour, KIWI rammed the submarine three times before I-1 finally struck a reef and was wrecked. Later, on 7th April 1943, MOA was sunk at Tulagi by enemy air attack; five ratings were killed and 15 injured. In August Tui and an American floatplane sank another large Japanese submarine, I-17, off New Caledonia. HMNZ Ships Gale and Breeze joined the deployed flotilla.
Leander took part in the night action of 12-13 July 1943 known as the Battle of Kolombangara, against two groups of Japanese destroyers and one cruiser. In this action torpedoes damaged US Ships USS Honolulu and St Louis, and Leander. A United States destroyer was also lost. Leander's casualties were 28 killed and 15 injured, but thanks to superb damage control she made Tulagi for temporary repairs before steaming to Auckland with USS Radford as an escort from Espiritu Santo. Subsequently she proceeded to Boston, USA for permanent repairs and paid off from the RNZN, having completed seven and a half years' service.
With both New Zealand cruisers out of action the Admiralty agreed to assign another cruiser to the RNZN. Thus the Officers and Ship's Company of Achilles commissioned HMNZS Gambia as a unit of the Royal New Zealand Navy on 22 September 1943.
By January 1944 the submarine threat to New Zealand was minimal and the RNZN responded to a request to deploy its 12 Fairmile B motor launches to the Solomons. The 80th and 81st ML Flotillas deployed to the theatre in two groups, in March, being employed on convoy escort and anti-submarine patrol duties around the Solomons and Bougainville, until mid 1945.
An unheralded contribution to the Solomons campaign was 11 RNZN Telegraphists attached to the Royal Australian Navy (RAN) to assist several local European residents in coast watching duties and intelligence gathering. Several had close encounters with Japanese; two were awarded the Distinguished Service Medal.
Throughout WW II the RNZN was closely involved in the production of radar sets, both for installation on board ships and for stations. In 1943 Admiral Halsey, Commander in Chief South Pacific asked for some New Zealand radar sets for use ashore in the Solomons. These were to be mobile gunnery control units, mounted in trucks and in April the first sets were deployed to the Russell Islands, north of Guadalcanal. A request for additional sets was subsequently received and although some were delivered, production capacity was limited; by the year's end newer American sets were arriving in sufficient quantities.
From providing accommodation for the Commander South Pacific and training facilities for many of the Marines involved in the fighting ashore, to supplying cruisers and smaller vessels, New Zealand was closely involved in the struggle for the Solomons. This brief overview omits both the New Zealand Army and Royal New Zealand Air Force contributions to the campaign. For the RNZN it was a major commitment that continued until the Japanese surrender, a commitment that incorporated both the tragedy and triumphs of war.