Time and Tides

Sun (Auckland), Volume I, Issue 246, 7 January 1928, Page 6

Time and Tides

AUCKLAND HARBOUR LAY-OUT

Allowances for Currents

ALTHOUGH it is over 20 years since, in 1904, the Auckland Harbour Board first approved of the principle according; to which harbour development is now progressing, changing conditions and the light of later knowledge hai e brought no substantial modification of the plan. This may be either a fine tribute to the soundness of the scheme, or an indication that the Harbour Board cannot or will not alter it.

TF the Harbour Board takes the former view, it is adopting a viewpoint not shared by all, and directly opposed by people closely concerned — the shipping representatives. Among those who disagree with the plan on which the Auckland wharves are being built are the marine superintendent of one of the largest shipping companies associated with the New Zealand trade, one of Auckland’s most influential shipping managers, and at least one master mariner commanding a big liner. Some years ago a member of a powerful English shipping concern

watched an overseas boat berthing at the Queen’s Wharf, and was led to remark: “That is a ponderous business.” To handle the big ship in the strong tide was a task requiring slow and careful navigation. Tidal influence at Auckland has always been pronounced, and it was to counteract it that the eastern and western breakwaters, or tide deflectors, were • incorporated in the plan. While these structures may have helped to some extent, it is common knowledge among shipping men that they have not eliminated the trouble. Strong tidal currents still eddy about the wharves, and they occasionally make the berthing of a big ship an extremely awkward process. ECCENTRIC CURRENTS

There are sometimes eccentric currents, possibly accentuated by .the harbour works. Often there is still an ebb current to be seen at the end of, say, the Queen’s Wharf, while the old ships anchored in -he stream are already swinging with the flood. Reclamation and the construction of the

wharves have, of course, greatly intensified the tidal sweep. Kvery extra yard of spoil, every foot of harbour wall, and every pile driven for the extension of the piers—all these must ultimately play their parts in narrowing the Waitemata, compressing its currents, and accentuating the play of the tides. With shipping men it is more or less axiomatic that wharves in a tidal harbour, or in a reach so strongly invaded by tidal currents, should lie in the direction of the tides. This principle is violated in the Auckland lay-out, where the main wharves. Queen’s Wharf, Central Wharf, and Prince’s Wharf, lie directly athwart the currents. Difficulties in berthing large ships are hence charged by navigators to the lay-out of the harbour. It is asserted that when the plan was developed in 1904 shipping men even then protested that the scheme involved a departure from accepted practice. They sighed for the retention of the old T wharves, of which the original Queen's Wharf was a good example. In Wellington this principle of tees is still demonstrated, even though the port there is almost entirely free from the tidal currents so pronounced in the Waitemata. INDEPENDENT REPORTS It is also recalled that the controversy as to the plan since followed was not restricted to exchanges between the board and the shipping men. Independent opinions were called for by the board, and after months of deliberation three separate reports, from three separate engineers, were considered. Of the three reports, the one endorsed by the board was that of its own engineer. The shipping interests in Auckland realise now that it is too late to hope for so radical a development as a change of plan, hut they do contend that the construction of future wharves on an angle parallel with the King’s Wharf is unnecessary, unless from the engineering viewpoint all future practice is to be governed by the angle at which the King’s Wharf is set. In the past it has been hinted that the construction of the wharves on an angle is to offset tidal influences, but navigators have been known to assert that it gives them no assistance whatever. Another suggestion is that the direction of the gullies, which form funnels for the wind, led to the jlevelopment of the angular plan, bat this, too, seems obscure. The main difficulty seen by shipping men in the angular lay-out is the fact that swinging room at the eastern end, where the export wharf will be close to the eastern breakwater, will be seriously restricted. In Mr. Hamer’s original plan, there was provision for only two piers between the King’s Wharf and the eastern breakwater, but later adjustments provided for three piers, set on an angle, with a corresponding risk of congestion.