Most cruises in Alaska explore the sub-Arctic Inside Passage. Few sail into the Arctic Circle, but the ones that do – such as Hurtigruten Expeditions, National Geographic Lindblad Expeditions and Seabourn – sail past Point Barrow. They may also stop at Herschel Island, which has Inuvialuit dwellings and a 19th century whaling station.

Alasdair sailed this stretch in the opposite direction, from Canada’s North West Passage. He says, “I saw a herd of musk oxen on Herschel Island, and got tipped out of my dingy while going ashore for fuel at Barrow Point.

“Alaska’s north coast is fairly dull. There are no mountains, glaciers or icebergs like in Greenland, and you can have days where the horizon is just grey. The water is quite shallow and not particularly well chartered, so big ships can ground there."