In the 1940s Wanganui was a city boasting a busy port that dated from the 1800s, and a sizeable airport which had opened in 1931. New Zealand was physically many miles from the theatres of war in Europe, but the threat of Japanese invasion brought the realities of war much closer to home.
Wanganui airport, south coast and Landguard Bluff Battery from the observation post
By June 1940 Wanganui Airport was one of sixteen landing fields and four defence aerodromes in New Zealand, along with two RNZAF stations in Fiji and one in Tonga, which the Air Force had committed to defend. The Air Force, however, had few means of active local defence. Eventually it was agreed that the Air Force would defend its aerodromes up to the perimeter, and the Army beyond that. The Army was also responsible for defence works for landing grounds. The Public Works Department assisted with technical and on-site design and construction tasks.
By March 1941 the Director of Works for aerodrome defence called for a list of landing grounds within 30 kilometres of the coast, including at Wanganui. But by October it was decided that the port in Wanganui did not require fixed defences after all, being vulnerable only to small raiding force attacks for which an independent local infantry company already existed.
A cylindrical type pillbox at Castlecliff
In February 1942 the situation had changed again as a result of the Pacific crisis, and defence of the local port became more urgent. Wanganui was allocated a US 155mm field gun, although senior defence officials decreed that the port could be adequately defended by a beach defence battery with light field guns alone. In any case, the US gun did not eventuate because by 1942 these weapons were in limited supply.
Construction of local coastal defence infrastructure finally got underway in 1942. A secret report from March of that year indicates that while the New Zealand Home Guard numbered around 11,000 personnel, only 800 rifles were available, so the structures were more to boost morale than to provide real defence should an enemy attack eventuate.
SS Port Bowen being unloaded from the port side after being beached (W-S-W-154)
Twenty-eight gun emplacements, or pillboxes, were planned for Wanganui, although only around 15 were actually built. The project was delayed because metal baffles for the loopholes had to be cut at Eastown Railway workshops from plate salvaged from the SS Port Bowen, which had grounded at Castlecliff in 1929. The ship also provided steel for an anti-tank barrier at Lyall Bay in Wellington.
The term “pillbox” dates back to 1917 when it was first used for structures used by the Germans during World War I. Ten pillboxes are still visible locally: at Mōwhanau Beach, between Castlecliff Beach and the river mouth, and along the south coast. All are arrowhead types apart from one round design near Morgan Street. Two additional defence structures, including a gun battery, are also still visible at Landguard Bluff. All were sited so their fields of fire overlapped.
An arrowhead-type pillbox at Castlecliff
New Zealand pillboxes varied from a box design in the north to the familiar arrowhead (T49) design locally and a cylindrical design further south (although two cylindrical pillboxes were built locally). Arrowhead pillboxes had a central firing area with wings either side for living quarters. The cylindrical design was developed by Humes Pipes of Christchurch to support, and to benefit from, the war effort.
Construction of the Wanganui Battery at Landguard Bluff began in June 1942 and was completed later that year at a cost of £3950. A 5-inch US Navy type BL MkVIII gun on a MkXV mount was installed on the reinforced pad at the front of the facility. Camouflage works were completed the following summer.
A Barr and Stroud 3m FT29 rangefinder was installed for aircraft observation. Barr and Stroud was a Scottish optical engineering firm (in the late 1950s they built Scotland’s first computer).
The interior of an arrow-head type pillbox
The Wanganui Battery was manned between 1942 and October 1943 by one army regular for every three Home Guards, and later, by a skeleton crew. By November 1944 the gun was dismounted and returned to store and the Battery was abandoned.
By March 1943 Wanganui had spent £50,000 on defence, including obstruction of the airfield by driving posts into the runway and laying barbed wire to secure local beaches.
Fifty-four roadblocks in the form of large concrete blocks were installed locally, along with 120 road or rail blocks throughout the wider district, including at Gentle Annie, Whangaehu Rail Bridge, Ūpokongaro, and the Aramoho railway bridge.
A Type J anti-tank ditch was constructed from the river north through Castlecliff. It had silted up by early 1943 and required re-excavating and the installation of double weirs to prevent further erosion.
The main principle of local defence was to hold the enemy off until the last round was fired, and the last man was down. Fortunately, our resolve was never put to the test.
For further reading see Defending New Zealand by Peter Cooke.