Although New Zealand possesses a very lengthy coastline in proportion to its area, it is not well endowed with natural harbours. In the North Island, Auckland and Wellington are the only two safe natural harbours of which the fullest commercial use can be made. On the east coast of the North Auckland Peninsula several deep and sheltered harbours exist, but as the surrounding country is comparatively undeveloped they are of little economic consequence at present. In the South Island the Marlborough Sounds and the West Coast Sounds form perfect land-locked harbours, but owing to their situations and to the rugged nature of the terrain they have, with the exception of Queen Charlotte Sound, little or no commercial utility. Where vital localities have not been endowed with ideal harbours, it has been necessary to improve existing facilities by dredging and breakwater construction. In this manner efficient ports capable of accommodating overseas vessels have been formed at Lyttelton, Otago, and Bluff.
On the west coast of both islands the strong ocean drifts and high seas cause shoaling at river mouths and harbour entrances, while on the east coast of the South Island similar circumstances prevail due to the large quantities of shingle brought down by rivers being spread along the coast by ocean currents. The mountainous nature of the country makes the haulage of goods to and from the better-equipped natural harbours both costly and difficult, and the construction and maintenance of further ports at various points along the coasts of both islands has been necessary either by dredging river mouths or by harbour construction work.
In the early history of New Zealand, ships were the main form of transport of passengers and goods from one part of the country to another. The development of the railway and roading systems of New Zealand has gradually reduced the volume of coastal shipping, which has now also been encroached on by air transport. The volume of the coastal cargo trade is nevertheless still substantial and there is no sign yet that its days are numbered. Known developments in air transport are unlikely to displace shipping between New Zealand and overseas ports.
Of the numerous New Zealand rivers few are of sufficient length or volume to be navigable; moreover, owing to the high relief of the country, they are mostly swift flowing, while nearly all are obstructed at their mouths by bars. For the purpose of internal communication, therefore, they are of little economic utility and only in two or three isolated instances have they been thus consistently used. With improved roading conditions their traffic has become negligible even in these cases.
The Bay of Islands was the first New Zealand port used by commercial shipping, but port development soon followed in other northern harbours such as Hokianga, Mangonui, and Auckland. Wellington came later, followed by New Plymouth. With settlements becoming established in the South Island, shipping was next recorded at Nelson, Akaroa, and Port Chalmers. By 1853, 11 ports were receiving shipping direct from overseas. The number of ports in use by overseas vessels increased during the goldrush period of the sixties, but later decreased to a number which has not changed greatly during the past 50 years.
Most harbours with any volume of commercial activity are controlled by harbour boards whose constitution, functions, and powers are set out in the Harbours Act 1950, supplemented by such local Acts as are passed in respect of each board and such general legislation of the country as affects them. A harbour board (other than those whose members are members of a local authority) consists of elected members. One or more members of each board represent one or more constituent districts, with the district represented by the total membership having some relationship to the sphere of influence of the imports and exports of the port. There are 33 harbour boards, 23 of which are autonomous bodies and 10 whose members comprise the members of the territorial locality authority.
Under the Harbours Act the Minister of Marine and the Marine Department are responsible for the administration of harbours where there is no harbour board. Until 1959 the Department operated the port of Picton, and it still carries out the full functions of a harbour board at Westport.
The years since the Second World War have seen substantial development of ports in New Zealand to make good the leeway lost in that period, and to keep pace with the expanding economy and with the increase in size and number of ships, both in the coastal and overseas trades. This development has occasioned healthy rivalry between ports, each seeking naturally its full share of the trade. Since 1945 harbour boards have been authorised to borrow about £40 million for development. As a consequence of the centralisation of shipping during the war, numbers of the smaller ports let their port facilities deteriorate and in the immediate post-war years they found great difficulty in re-establishing the port and the trade, with the result that several of the boards were dissolved. The trend today is for fewer harbours, each, however, equipped with modern facilities to obtain a better turn-around of ships.
A number of the country's non-capital ports are associated with special industries: Tauranga, pulp and paper and log exports; Westport and Greymouth, coal; and Whangarei, oil refinery.
Auckland Harbour can be entered by a vessel drawing up to 33 ft. In the inner harbour there is anchorage in depths of from 5 to 12 fathoms. There are four channels of approach to the port, but Rangitoto Channel is the only one suitable for deep-draught vessels. The total length of berthage available in the port is 27,301 ft, 12,512 ft being devoted to coastal shipping and 14,789 ft to overseas vessels. All berth-age for overseas vessels is served by railway sidings; 11 berths are suited to the loading of refrigerated cargo. With the exception of the Chelsea sugar wharf on the North Shore, all wharves are concentrated in the Quay Street area.
Calliope Dock is 605 ft long and 65 ft wide at the blocks. The harbour board also operates two slipways which can accommodate vessels of 600 tons and 200 tons. The 80-ton self-propelled crane Mahua has sufficient height and radius to enable it to serve the largest ships. Three powerful twin-screw tugs are available.
Total shed cargo space is approximately 950,000 sq. ft. Few ports in the world enjoy better cargo-handling facilities. Cranes average four per berth, and at seven of the berths there are five per berth. Twelve lighters are provided to assist unloading of vessels. Stevedoring strength is 1,700 men.
Wellington Harbour contains an area of about 20,000 acres, having depths varying from 6 to 14 fathoms. The entrance varies from 7 to 8 fathoms with a deep-water channel 1,000 ft wide. The current never exceeds 2½ knots and the tide varies from 2 ft 6 in. to 4 ft 6 in.
The harbour board has 10 wharves directly alongside the city business centre, with total lineal berthage of 23,616 ft and with depths alongside varying from 16 ft to 41 ft; 8,481 ft of berthage is linked up with the national railway system. There are seven other wharves in the harbour with 3,712 ft lineal berthage. Miramar (coal) and Burnham (oil) wharves are in Evans Bay, and the Point Howard (oil) wharf is at the northern end of the harbour. Overseas berths are generally served with four to six electric cranes per berth. There are 33 cargo stores with capacity of approximately 64,000 tons and all are equipped with overhead lifting gear with capacities of from 30 cwt to 5 tons. A coal berth has six 4½-ton grabbing cranes for delivery of coal to road and rail transport through four 60-ton self-propelling hoppers. One fixed 10-ton hydraulic crane and a floating crane with lifting capacity of up to 80 tons are available for heavy lifts. There is a floating dock with lifting capacity of 17,000 tons. Two privately owned tugs are available at the port.
More than half of New Zealand trans-shipment trade takes place at Wellington mainly on account of its geographical location.
Lyttelton is the third port in New Zealand. For exports it serves the great primary-producing plains of Canterbury Province. The port is connected to the City of Christchurch through a 1¾-mile tunnel through the Port Hills. A dredged channel of about 2½ miles in length and 600 ft in width has a depth of 32 ft at low water and is maintained by the suction dredge. Canterbury. The inner harbour is situated about 4 miles from the entrance and is formed by breakwaters. Inside the breakwaters, depths vary from 20 to 38 ft at low tide. Tidal range is 7 ft springs, 5 ft neaps.
The total effective berthage is 10,338 ft, and this will accommodate 10 overseas and six intercolonial or coastal ships. All wharves except the oil wharf are connected to the national railway system. Coal and oil bunkering service is available. There are 28 cranes: 24, 5 ton; and four, 3 ton. Electric capstans facilitate the moving of railway wagons. The floating crane Rapaki has a lifting capacity of 80 tons. The graving dock will accommodate a vessel 462 ft by 52 ft by 18 ft draught, and a patent slip takes vessels of 250 tons dead weight and maximum length of 115 ft. Two steam tugs are available.
The port of Tauranga has recently been developed to deal mainly with the export of pulp and paper from Tasman Pulp and Paper Co. It is now the fourth largest port in respect of the quantity of cargo handled, and the second largest in respect of the volume of outward overseas cargo. A bar with a least depth of 23 ft over it lies at the entrance approaches. Tidal range: neaps 5 ft, springs 7 ft. The maximum size for vessels entering the port is 560 ft, and the maximum draught in approach channels is 24 ft at high water.
At Mount Maunganui there is a maximum overall berthage of 2,000 ft, with depths ranging from 25 to 32 ft. At Tauranga the Railway wharf has berthage accommodation of 541 ft and a least depth alongside of 16 ft at low water. A mobile crane is situated on Railway wharf, with a maximum lift of 4½ tons.
Cargo sheds at Mount Maunganui have a floor area of 38,325 sq. ft., but 24,825 ft of this is used only for the products of the Tasman Pulp and Paper Co. In addition there are two open-storage areas of 28,500 and 112,000 sq. ft. respectively. At the Railway wharf there are two sheds of 650 and 250 tons capacity. Two dry-cargo lighters of 60 tons capacity are available.
Within the entrance the harbour extends about 12 miles and at its head stands the city and port of Dunedin. About half way lies the port of Port Chalmers. The majority of large vessels are berthed at Dunedin. The tidal range is 4·2 ft neaps and 57 ft springs.
The maximum size and draught permissible for negotiating Victoria Channel, which runs from Port Chalmers to the city wharves, are as follows: length, 540 ft; beam, 72 ft; draught, 25 ft. The maximum for Port Chalmers are: length, 800 ft; beam, 90 ft; draught, 32 ft. Total berthage is 8,594 lineal feet. Most wharves are linked with the national railway system.
There are two electric cranes serving one berth at Port Chalmers. In addition, three serve two berths at Victoria wharf and two serve two berths at Birch Street, Dunedin. There are no wharf sheds at Port Chalmers, but at Dunedin there are 18 sheds with a maximum capacity of 2,812,248 cu. ft. One tug is available. The port has two graving docks at Port Chalmers for vessels of 530 ft and 300 ft length respectively. These are adjacent to ship-repair workshops. Most of the trade is handled at Dunedin, but final loading of large overseas vessels must be done at Port Chalmers.
by William Alexander Cullen, Executive Officer (Shipping and Harbours), Marine Department, Wellington.