Cook Strait is a strait between the North and South Islands of New Zealand. It connects the Tasman Sea on the west with the South Pacific Ocean on the east.

To the south the coast runs runs 30 kilometres along Cloudy Bay and past the islands and entrances to the Marlborough Sounds. To the north the coast runs 40 kilometres along Palliser Bay, crosses the entrance to Wellington harbour, moves past some Wellington suburbs and continues another 15 kilometres to Makara beach.

The strait is named after James Cook, the first European commander to sail through it, in 1770. In Māori it has the name Raukawa or Raukawa Moana. Raukawa may mean "bitter leaves".

Cook Strait is regarded as one of the most dangerous and unpredictable waters in the world. In good weather one can see clearly across the strait. At its narrowest point 23 kilometres (14 miles) separate Cape Terawhiti in the North Island from Perano Head on Arapawa Island in the Marlborough Sounds. Counter-intuitively, at this point the South Island's coast lies further north than that of the North Island.

History

In Māori mythology, Cook Strait was originally discovered by Kupe the navigator. Kupe followed, in his canoe, a monstrous octopus called Te Wheke-a-Muturangi across Cook Strait and destroyed it in Tory Channel or at Pātea. Other legends: Te Whanganui-a-Tara#Legend of Whanganui-a-Tara.

When Dutch explorer Abel Tasman first saw New Zealand in 1642, he thought Cook Strait was a bight closed to the east. He named it Zeehaen's Bight, after the Zeehaen, one of the two ships in his expedition. In 1769 James Cook established that it was a strait which formed a navigable waterway.

Cook Strait attracted European settlers in the early 19th century. Because of its use as a whale migration route, whalers established bases in the Marlborough Sounds and in the Kapiti area. From the late 1820s until the mid 1960s, Arapawa Island was a base for whaling in the Sounds. Perano Head on the east coast of the island was the principal whaling station for the area. The houses built by the Perano family are now operated as tourist accommodation.

During the 1820s Te Rauparaha lead a Māori migration to, and the conquest and settlement of, the Cook Strait region.

From 1840 more permanent settlements sprang up, first at Wellington, then at Nelson and at Wanganui (Petre). At this period the settlers saw Cook Strait in a broader sense than today's ferry-oriented New Zealanders: for them the strait stretched from Taranaki to Cape Campbell, so these early towns all clustered around "Cook Strait" (or "Cook's Strait", in the pre-Geographic Board parlance of the times) as the central feature and central waterway of the new colony.

Between 1888 and 1912, a dolphin named Pelorus Jack became famous for meeting and escorting ships aroung Cook Strait. Pelorus Jack was usually spotted in Admiralty Bay between Cape Francis and Collinet Point, near French Pass, a channel used by ships travelling between Wellington and Nelson. Pelorus Jack is also remembered after he was the subject of a failed assassination attempt. He was later protected by a 1904 New Zealand law.

At times when New Zealand feared invasion, various coastal fortifications were constructed to defend Cook Strait. During the second world war, two 9.2 inch gun installations were constructed on Wrights Hill behind Wellington. These gun could range 18 miles across Cook Strait. In addition, another thirteen 6 inch gun installations were constructed around Wellington, along the Makara coast, and at entrances to the Marlborough Sounds. The remains of most of these fortifications can still be seen.

The Pencarrow Head Lighthouse was the first permanent lighthouse built in New Zealand. Its first keeper, Mary Jane Bennett, was the first and only female lighthouse keeper in New Zealand. The light was decommissioned in 1935 when it was replaced by the Baring Head Lighthouse.

A number of ships have been wrecked with significant loss of life, such as the City of Dunedin in 1865, the Lastingham in 1884, SS Penguin in 1909 and the Wahine in 1968.

Geology

The shores of Cook Strait on both sides are mostly composed of steep cliffs. The beaches of Cloudy Bay, Clifford Bay, and Palliser Bay shoal gently down to 140 metres, where there is a more or less extensive submarine plateau. The rest of the bottom topography is complex. To the east is the Cook Strait Canyon with steep walls descending eastwards into the bathyal depths of the Hikurangi Trench. To the north-west lies the Narrows Basin, where water is 300 and 400 metres deep. Fisherman's Rock in the north end of the Narrows Basin rises to within a few metres of low tide, and is marked by waves breaking in rough weather. A relatively shallow submarine valley lies across the northern end of the Marlborough Sounds. The bottom topography is particularly irregular around the coast of the South Island where the presence of islands, underwater rocks, and the entrances to the sounds, create violent eddies. The strait has an average depth of 128 metres (420 feet).

The South and North Islands were joined during the last ice age.

Islands

Tidal flow

The tidal flow through Cook Strait is particularly interesting, as on each side of the strait the tide is almost exactly out of phase so that high water on one side meets low water on the other. Strong currents result, with almost zero tidal height change in the centre of the strait. Yet, although the tidal surge should flow in one direction for six hours and then the reverse direction for six hours, a particular surge might last eight or ten hours with the reverse surge enfeebled. In especially boisterous weather conditions, the reverse surge might be entirely overcome so that the flow remains in the same direction through three surge periods and longer. A further complication for Cook Strait's pattern of current flow is that the tides at the north end have the ordinary two cycles of spring-neap tides in a month (as found along the west side of the country), but the south end's tidal pattern has only one cycle of spring-neap tides a month, as found on the east side of the country.

Tidal energy

In April 2008, a resource consent was granted to a small company for the installation of a $10 million experimental underwater tidal stream turbine capable of producing one megawatt of power. The turbine will be 14 metres in diameter and constructed of carbon fibre. It will be placed in eighty metres of water, 4.5 kilometres due south of Sinclair Head, in waters known as the “Karori rip”. Power from the turbine will be brought ashore at Vector's Island Bay substation. The company claims there is enough tidal movement in Cook Strait to generate 12 GW of power, more than one-and-a-half times New Zealand's current requirements.

Cables

Electric-power and communication cables link the North and South Islands across Cook Strait. These cables are currently operated by Transpower

• Power cables: A high-voltage direct current (HVDC) system uses three undersea cables. During dry periods, this gives the South Island access to gas and coal power generated in the North Island. Likewise, during peak winter periods, it gives the North Island access to power from the large hydroelectric installations in the South Island. The submarine cables are laid on the seabed within a legally defined zone called the cable protection zone (CPZ). The CPZ is about seven kilometres wide for most of its length. It narrows where the cables enter the water at Fighting Bay on the South Island and at Oteranga Bay, Cape Terawhiti, in the North Island. Fishing activities and anchoring boats are prohibited within the CPZ. Transpower has a current proposal to spend nearly $700 million upgrading the electricity link. If implemented, this will have a capacity of 1200 MW by 2014.
• Communication cables: Fibre optic cables carry telecommunications across Cook Strait, used by New Zealand’s main telecommunication companies for domestic and commercial traffic and by Transpower for control of the HVDC link

Marine life

Giant squid specimens have been washed ashore on Cook Strait or found in the stomachs of sperm whales..

A colony of male fur seals has long been established near Red Rocks on the Makara Coast, west of Wellington.

Game fishing

Cook Strait offers good game fishing. Albacore tuna can be caught from January to May. Broadbill swordfish, bluenose, mako sharks and the occasional marlin and white shark can also be caught.

Transport

Ferry

Regular ferry services run between Picton in the Sounds and Wellington. Although Cook Strait is only 24 kilometres wide at its narrowest point, the ferry journey takes 70 kilometres. The strait often experiences rough water and heavy swells from strong winds, especially from the south. New Zealand's position directly athwart the roaring forties means that the strait funnels westerly winds and deflects them into northerlies. Due to this the Cook Strait is regarded as one of the most dangerous and unpredictable waters in the world.

Air

Swimming

According to Māori mythology, the first woman to swim Cook Strait was Hine Poupou. She swam from Kapiti Island to Dürville Island with the help of a dolphin. Other Māori accounts tell of at least one swimmer who conquered the strait in 1831.

In modern times, the strait was first swum by Barrie Devenport in 1962. Lynne Cox was the first woman to swim it in 1975, famously stopping often and diving to the sea floor to collect shellfish and crayfish for her husband. The most prolific swimmer of the strait is Philip Rush, who has crossed eight times, including two double crossings. Aditya Raut was the the youngest swimmer at 11 years. By 2008, 71 single crossing had been made by 61 individuals, and 3 double crossings had been made by 2 individuals. Crossing times are largely determined by the strong and sometimes unpredictable currents that operate in the strait.

Timeline

• Mists of time: The mythical navigator Kupe follows, in his canoe, the octopus Te Wheke-a-Muturangi across Cook Strait.
• 1642: Abel Tasman mistakes Cook Strait for a bight.
• 1769: James Cook establishes it is a strait
• 1822: Ngati Toa migrates to Cook Strait region, led by Te Rauparaha.
• 1855: Severe earthquake on both sides of Cook Strait.
• 1866: Cook Strait submarine telegraph cable laid.
• 1879: Kangaroo lays the first Telegraph cable across Cook Strait.
• 1909: SS Penguin wrecked in Cook Strait, 75 people die.
• 1920: First aeroplane flight across Cook Strait.
• 1935: Air services begin across Cook Strait.
• 1962: Cook Strait rail ferry service begins.
• 1962: Barrie Devenport swims the strait.
• 1964: Cook Strait power cables laid.
• 1968: TEV Wahine wrecked at entrance to Wellington harbour, 53 people die.
• 1975: Lynne Cox is the first woman to swim the strait.
• 1979: Paul Caffyn crosses the strait in a sea kayak.
• 1984: Rush Philip swims the strait both ways.
• 1991: Five new power and communication cables laid
• 1994: First fast-ferry service begins operation across Cook Strait.
• 2002: Two further communications cables laid.
• 2005: The retired frigate HMNZS Wellington is sunk off Wellington as an artificial reef.

See also

• Aotearoa Wave and Tidal Energy Association

Notes

References

• Grady, Don (1982) Perano Whalers of Cook Strait, 1911-1964. Intl Specialized Book Service. ISBN 978-0589013929

External links

• Cook Strait: Ship Wrecks, Swells and Gales
• New Zealand's Cook Strait Rail Ferries:
• NZ: Chance to turn the tide of power supply EnergyBulletin.net
• Lewis, Keith Submarine cables Te Ara - the Encyclopedia of New Zealand, updated 21-Sep-2007.
• History of Cable Bay Station
• A Powerful link: The Cook Strait Cable
• NZ Documentary Film (2007) Fish & Ships The Island Bay fishing fleet.