Wild weather halted ferries between New Zealand’s main islands again. Why isn’t there a tunnel?

WELLINGTON, New Zealand (AP) — Wild weather during New Zealand ’s peak summer holiday period has disrupted travel for thousands of passengers on ferries that cross the sea between the country’s main islands.

The havoc wrought by huge swells and gales in the deep and turbulent Cook Strait between the North and South Islands is a recurring feature of the country’s roughest weather. Breakdowns of New Zealand’s aging ferries have also caused delays.

But unlike in Britain and Japan, New Zealand has not seriously considered an undersea tunnel beneath the strait that more than 1 million people cross by sea each year. Although every New Zealander has an opinion on the idea, the last time a prime minister was known to have suggested building one was in 1904.

A tunnel or bridge crossing the approximately 25-30 kilometers (15-18 miles) of volatile sea is so unlikely for the same reason that regularly vexes the country’s planners — solutions for traversing New Zealand’s remote, rugged and hazard-prone terrain are logistically fraught, analysts said.

Why isn’t a tunnel practical?

A Cook Strait tunnel would dramatically reduce the three- to four-hour sailing time between the North Island, home to 75% of the population, and the South.

“But it would chew up, off the top of my head, about 20 years of the country’s entire transport infrastructure development budget in one project,” said Nicolas Reid, transport planner at MRCagney.

He estimated a cost for a tunnel of 50 billion New Zealand dollars ($28 billion), comparable in today’s terms to the price of the undersea tunnel that connects Britain and Europe by rail. New Zealand is the same size as the United Kingdom — but the U.K. has a population of 69 million, more than 13 times New