The strait itself, crossed by four major fault lines, 23 kilometres across at its narrowest point and of depths of up to 365 metres, lies in the westerly wind belt known as the ‚roaring forties‘. Gales of up to 240 km/hr have been recorded in the vicinity of Wellington.
The strait represents the only gap in a chain of mountains extending over 1,400 kilometres, from Puysegur Point on the south-west tip of the South Island to the North Island’s East Cape. It is thus a natural channel through which airstreams approaching central New Zealand are diverted and funnelled. As well as for its winds, the strait has a deserved notoriety for currents as treacherous as they are erratic.
The Cook Strait ferry
For over a century the turbulent waters of Cook Strait divided the country’s railway system into virtually two independent and unconnected sections. In December 1862 the Southland Times recommended that a New Zealand Grand Junction Railway be built from Bluff to the Bay of Islands, with ‚powerful steamers spanning the vexed waters of Cook’s Straits‘. Prime Minister Richard Seddon in 1898 suggested a ferry service between Picton and Wellington, and four years later his eventual successor, Sir Joseph Ward, predicted that a steamer rail ferry was ‚bound to come‘. Several committees reported unfavourably on the proposal, and not until August 1962 was the first roll-on roll-off car-rail ferry Aramoana put into service on a run which represented a milestone in the country’s road-and-rail services.
The ferries take about 3 hours 20 minutes to cross the strait, leaving Picton and Queen Charlotte Sound by way of Tory Channel and making an essentially east-west passage. Only half of this time is spent in the open sea, one hour being spent in the Sounds and some 40 minutes in Wellington Harbour. For points of interest in Queen Charlotte Sound and Tory Channel, see Marlborough Sounds.