The ship’s arrival probably woke most of the town with its foghorn being sounded at regular intervals in accordance with international regulations.

Harbour master Rob Lovell said the fog rolled in just as he and assistant harbour master Joseph Pereira were taking another ship out about 5am.

“The fog bank hit us as we were leaving,” Mr Lovell said.

“It was all clear when we left the berth and by the time we got to the breakwater we couldn’t see a thing.

“This morning was a classic temperature inversion which means the air sits on the sea and stays there.”

When the men transferred to the Panamax ship Amphion they tracked the dew point temperature before deciding whether to bring the ship into port.

“It was too thick to start so we waited bit to see if we could get a degree difference between the dew point temperature and temperature before we could safely start bringing the ship in.”

Mr Lovell said the navigation technology they used to bring the ship in was the best in the world.

“The ship has two radars as well as a GPS,” he said.

“We also take on board with us a portable navigation unit that has two GPS antenna so we get accuracy within metres.

“None of it failed but you have to enough in reserve before you attempt a job like that.”

“We had quadruple redundancy, in addition to that the wind was calm.”

Mr Lovell said he also had previous experience navigating ships through fog in the English Channel.

He said there was limited risk bringing the ship in under Monday’s conditions and he found the middle of the navigating channel in the harbour using radar.

“If we hadn’t brought the ship in when we did it would stayed out until 10am when the fog finally lifted,” he said.

“I couldn’t see any point in that, and it would have been delayed a whole lot longer.”

As the ship approached the port the fog lifted and disappeared just as quickly as it had arrived.