• litchralee@sh.itjust.works
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    3 months ago

    The knot is non-SI but perfectly metric and actually makes sense as a nautical mile is exactly one degree meridian

    I do admire the nautical mile for being based on something which has proven to be continually relevant (maritime navigation) as well as being brought forward to new, related fields (aeronautical navigation). And I am aware that it was redefined in SI units, so there’s no incompatibility. I’m mostly poking fun at the kN abbreviation; I agree that no one is confusing kilonewtons with knots, not unless there’s a hurricane putting a torque on a broadcasting tower…

    No standard abbreviation exists for nautical miles

    We can invent one: kn-h. It’s knot-hours, which is technically correct but horrific to look at. It’s like the time I came across hp-h (horsepower-hour) to measure gasoline energy. :(

    if you take all those colonial unit

    In defense of the American national pride, I have to point out that many of these came from the Brits. Though we’re guilty of perpetuating them, even after the British have given up on them haha

    An inch is 25mm, and a foot an even 1/3rd of a metre while a yard is exactly one metre.

    I’m a dual-capable American that can use either SI or US Customary – it’s the occupational hazard of being an engineer lol – but I went into a cold sweat thinking about all the awful things that would happen with a 25 mm inch, and even worse things with 3 ft to the meter. Like, that’s not even a multiple of 2, 5, or 10! At least let it be 40 inches to the meter. /s

    There’s also other SI-adjacent strangeness such as the hectare

    I like to explain to other Americans that metric is easy, using the hectare as an example. What’s a hectare? It’s about 2.47 acre. Or more relatable, it’s the average size of a Walmart supercenter, at about 107,000 sq ft.

    1 hectare == 1 Walmart

    • barsoap@lemm.ee
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      3 months ago

      We can invent one: kn-h. It’s knot-hours, which is technically correct but horrific to look at. It’s like the time I came across hp-h (horsepower-hour) to measure gasoline energy.

      Quite standard, actually. If you buy a fridge over here it’d say something like “150 kWh/a”, which is 17.12 Watts, which is how much the fridge uses on average. People don’t pay for Watts, though, but for kWh, that’s what’s on the bill so kWh/a is way more practical if you want to convert to €/a. Also if you put more than one number in Watts in the docs civilians might get confused, ideally the only one you put there is connection power.

      What’s a hectare?

      I actually have no idea. I know that it’s what farmers pick up women with but I have no real mental image of how much it is. 100m, sure, make that a square but it’s still somehow without meaning.

      but I went into a cold sweat thinking about all the awful things that would happen with a 25 mm inch,

      Blame the Swedes, or more precisely Carl Edvard Johansson, inventor and manufacturer of gauge blocks. Before that the US and Brits had slightly incompatible definitions of inches and he split the difference pretty much in the middle and rounded a bit and ended up producing 25.4mm gauge blocks, and only after that industry even started to be precise and actually adhere to proper measures – without wide availability of reference gauge blocks that was impossible. He should’ve rounded just a bit further.