Damage to the power and communications cables that run along the bottom of the Cook Strait would cost tens of millions of dollars to fix and likely take more than a year.

Transpower has a team which patrols the large Cable Protection Zone between Marlborough and Wellington and they took 1News reporter Jessica Roden on board this week after a series of concerning incursions this summer.

With the current warn weather, more Kiwis are taking to the water this summer but — for those looking to fish or drop anchor near the Cook Strait — it comes with a warning.

The Cable Protection Zone is 7km wide and stretches from Ōraumoa/Fighting Bay in Marlborough to Oteranga Bay in Wellington. Underneath it are a series of power and communications cables that are vital to the country’s infrastructure.

Transpower’s Mark Ryall, who is the General Manager Grid Delivery, says the cables are a vital part of the country’s infrastructure, carrying about 15% of the North Island’s power supply.

“A repair to the cables would be expensive, in the tens of millions and would take maybe over a year depending on when we can get a boat into New Zealand to enable us to fix it.”

After a trawler snagged the cables in the 1990s, Transpower commissioned and crewed a former Navy ship to patrol the zone. A three-erson crew patrol the area twenty-four-seven — every day of the year.

Each crew member takes a four-hour shift watching the zone and they spend 16 days at sea at a time. The ship is out in all but the most extreme conditions — when they take shelter and monitor the area with technology.

Skipper Callum Burson says they’re on the lookout for everything. “Trawling or fishing could damage the cables and even the smallest hook could pierce the armour.”

He says the locals all know about the zone and the main job is educating newcomers. “We ask that people know where the zone is, if people are coming out in the Cook Strait. And just do a bit of homework.”

The night prior to 1News visit, the crew responded to a mayday call, their job being to ensure any capsized vessel didn’t threaten the cables. A trawler was also fishing close by, which meant the crew positioned their ship over the protection zone to ensure the trawler didn’t get too close.

Unfortunately, Ryall said there’s already been issues this year. “The summer period’s obviously really busy for boaties. Christmas, New Years, everyone’s obviously on holidays.

“We’ve already had six or seven incidents in the strait in the zone where people have been fishing. Patrol have done their job, they’ve intervened, they’ve talked to them and we take an approach where we try to educate first.”

None of the boaties were given infringements but rule breakers can face a fine of up to $250,000 if they cause damage.

The consequences for the rest of the country if that happened could be huge as well.

“In a worst case scenario with damage to multiple cables, it could certainly have trouble running a network with enough capacity for everybody at certain times,” Ryall said.