In the UK, we went 'metric' in 1965. Feet and inches, Mph, etc are still very much in common useage though.

Could be because the marine and flight “industries” still use imperial?

Feet, knots, miles etc are still used for boats and anything that flies.

No, they don't use imperial. The mile you are talking about is the Nautical Mile[0] which is the consequence of having 90 degrees between the equator and the pole, then splitting each of those into 1/60[1] (also called a minute), which although arbitrary complements the base of degree based measurements. Today the nautical mile is defined as 1852 meters compared to 1,609.344 for the mile.

[0]: https://en.wikipedia.org/wiki/Nautical_mile

[1]: https://upload.wikimedia.org/wikipedia/commons/5/59/Nautic_m...

Yes I understand how the nautical mile works, the point was still that it’s not metric. Altitude and physical length units are still in feet tho, same goes for weight which is in long tonnes.

> Altitude and physical length units are still in feet tho, same goes for weight which is in long tonnes.

The article on suezmax[1] uses metric as the primary units, even in images/charts. The article on deadweight [2] explains that long tonnes were used historically but now metric tonnes are used. I don't know much about the units used for altitude in shipping

[1] https://en.wikipedia.org/wiki/Suezmax

[2] https://en.wikipedia.org/wiki/Deadweight_tonnage

Ah okay, so it is not a imperial feet/mile, but a nautic feet/mile. Okay, that makes sense then.

To speculatively answer your original question about why Business Insider reported the plans in US Customary units: It's an American media company. Albeit owned by a German publishing house. And the article was authored by someone out of London (where imperial units are still used commonly).

But if you check other sources on the same news (eg Chinese state media company Xinhua [1] used only metric, or the Russian state-owned RT [2] uses only metric, while the Canada-based Reuters [3] uses a bizarre mix of only-metric, only-imperial, and both) - They're all writing for their target audience. Without watching the original TV address, I couldn't say which was originally used.

[1] http://www.xinhuanet.com/english/africa/2021-05/16/c_1399483...

[2] https://www.rt.com/news/523483-suez-canal-expand-southern-st...

[3] https://www.reuters.com/world/suez-canal-chief-says-southern...

Knots and (nautical) miles aren't imperial. They're useful for navigation because a nautical mile is exactly the length of a meridian arcminute, and a knot is one nautical mile per hour. Makes these units easy to use on nautical charts.

Not in Europe where Im from

I’m also from Europe and i haven’t seen metric used for maritime or aircraft industries these are governed by intentional conventions.

Edit: I just checked even the French ship registration forms have tonnage in long tons (imperial) and boat dimensions in feet...