Prior to the outbreak of war with Japan, planning for the mining of major
ports and harbours was well underway by October 1941. But if General
Williams' requirements were to be met, (The Defencive Plan for New Zealand)
a controlled mining organisation would have to be set up. This involved the
provision of suitable minelaying vessels, a mine depot, a controlled mine
base to assemble the mines and their associated gear, advance bases for
prepared material in the vicinity of the minefield, adequate mining material
and properly trained personnel.
HMS Atreus and HMS Alsey were to lay eight minefields from
Whangaroa in the north to Akaroa in the south. £69,000 was allocated for the
Lyttelton & Akaroa minefields. HMS Atreus and HMS Alsey left
Auckland for the South Island on 5 January 1943. The Akaroa Minefield
consisted of four mine loops (each of 16 mines) and two guard loops. The
field was codenamed JL8.
The Atreus was a converted merchant steamer of 6546 tons gross
register, built in 1911 for the China Mutual Steam Navigation Co. (Alfred
Holt & Co.) of Liverpool. The Alsey was a converted trawler of 416
tons, built in 1932
After several sites in
Lyttelton harbour had been rejected, Tikao Bay in Akaroa harbour was
selected for the advanced base for the Lyttelton area. The Naval Board then
decided upon a fully equipped base similar to that at Islington Bay and, a
month later, in accordance with a policy of wide dispersion of ammunition
reserves, to build eleven magazines at Tikao Bay. The estimated cost of
these proposals was £97,440, as against £25,000 for the original base
scheme. Authority for the additional expenditure was given by War Cabinet at
the end of June 1942. But, following a visit to Tikao Bay in September 1942,
the Superintending Armament Supply Officer informed the Naval Secretary that
the magazine site was too far by road or sea from Lyttelton, the port to be
served. Moreover, the magazines as planned would be only 200 or 300 yards
away from the mining depot, with no natural feature to protect the one in
the event of an explosion in the other.
On completion in 1943 it comprised of a large wooden depot of 24,500 sq ft
(2275m2), a brick mine magazine, examination room and primer magazine. Land
was reclaimed and a wharf built for mine laying vessels.
When they arrived at Akaroa it was found that little progress had been made
with the shore buildings. Temporary huts were set up and the laying of the
minefield was completed by 15 January 1943. A few days earlier, Captain
Campbell of the Atreus was informed by the Naval Board that, because
of the change in the strategic situation’, the Lyttelton minefield was not
to be laid.
They also trained as many New Zealand officers and ratings as possible so
that the efficient operation and maintenance of the controlled minefields
would be assured after their departure. Yet, even before the ships had left
New Zealand, the first moves were being made in a reduction programme that
was to lead to the closing down of the first minefields only eleven months
after they had been laid.
It was eventually decided to build the magazines at Cass
Bay, about two and a half miles from Lyttelton.
The Tikao Bay mining base was
not completed till March 1943. It was then manned by an officer and fourteen
ratings, all specialists on loan from the Royal Navy.
Since a big reduction in the controlled mining
organisation was made shortly afterwards, Tikao Bay proved to be a white
elephant of even greater proportions than the Mahanga Bay depot at
Doubtless, in 1942, at that time the Government had felt bound to act on
the advice of their military adviser, General Williams, regarding the
defence of New Zealand against a possible Japanese invasion, which to many
appeared a near probability in the black months following Pearl Harbour.
But, though it could not be known at the time, Japanese sources have since
revealed that no attack on New Zealand was ever planned.
In respect of the minefields, it was agreed that the independent minefields
in Hauraki Gulf should remain at present, except those in the channels on
either side of Rakino Island, which were to be swept. The controlled
minefield in Whangaparaoa Passage was to be reduced to a care and
maintenance basis and that at Wellington to remain fully manned, the
position in respect of both to be reviewed early in 1944. In January 1944 it
was decided to dispose of all the minefields except that at Wellington. The
independent minefield at the Bay of Islands was to be swept and the
controlled fields there and at Whangaroa, Great Barrier, and Akaroa to be
fired. The minefield was fired on 21st February 1944.
Note: Two of the 69 mines laid in the Akaroa field are still
unaccounted for and may still be resting on the floor of Akaroa harbour.
Floating mines were still being washed ashore along the New Zealand
coastline as late as 1951. In all 1391 mines were laid around the New
Zealand coast by the Allies and 248 enemy mines by German raiders.
All stores were to be transferred to Islington Bay and Tikao Bay base was to
be closed down and offered to the Army.
The Royal New Zealand Navy , Waters, S. D. Historical Publications Branch,
1956, Wellington, Part of:
The Official History of New Zealand in the Second World War 1939–1945
Defending New Zealand, Ramparts on the Sea 1840-1950s,
Part 2, Peter Cooke, August 2000
Photos: Phil Moore, www.nzrifle.com
mine of the type laid in
Type L Mark II
The first reliable British contact-type mine, this was copied
from the successful German Hertz-horn contact mine. Production started in
early 1917, but it was not available in useful numbers until November 1917.
Spherical design. Total weight not available, charge was 320 lbs. (145 kg)
and used Hertz horns. Still in use during the early years of World War II.
of the type laid in around the Northern Coast and ports.
This is an acoustic-type
with a diameter of 40 inches, a length of 56 inches with an 8 inch belly
band, a weight of 562 pounds (without sinker), and an explosive of 320 to