Author Topic: Arithmetic that makes you cringe  (Read 28576 times)

hellymedic

  • Just do it!
Re: Arithmetic that makes you cringe
« Reply #275 on: 07 June, 2021, 01:02:43 am »
A knot is a nautical mile per hour.

A nautical mile (1852 metres) is a bit more than a statute mile (1609 metres).

Giraffe

  • I brake for Giraffes
Re: Arithmetic that makes you cringe
« Reply #276 on: 07 June, 2021, 08:11:59 am »
The pedant in me dislikes knots per hour.
Thanks for that, I know f-all about boats but my first through on reading that was "isn't knots a unit of speed?"  (I believe due to the expression "travelling at a rate of knots" which implies that whatever a knot is, it measure speed).
A rate of knots would be acceleration.
2x4: thick plank; 4x4: 2 of 'em.

ravenbait

  • Someone's imaginary friend
  • Pudge controls the weather.
    • Someone's imaginary friend
Re: Arithmetic that makes you cringe
« Reply #277 on: 07 June, 2021, 12:29:29 pm »

A rate of knots would be acceleration.

Does the phrase not date back to the time when speed was determined by counting knots in a rope attached to a drag that was put out the stern of a ship? So that would be "rate of knots counted per 30 seconds."

Sam
https://ravenbait.com
"Created something? Hah! But that would be irresponsible! And unethical! I would never, ever make... more than one."

T42

  • Old fool in a hurry
Re: Arithmetic that makes you cringe
« Reply #278 on: 07 June, 2021, 01:54:25 pm »

A rate of knots would be acceleration.

Does the phrase not date back to the time when speed was determined by counting knots in a rope attached to a drag that was put out the stern of a ship? So that would be "rate of knots counted per 30 seconds."

Sam

Probably for something like "per one turn of the small glass". It's probably OK to use if if you're still timing things other than eggs with sand-glasses, but most of us have moved on.

"Knots per hour" is just bloody ignorant (and/or BBC standard).
But they never got to Carcassonne.

Re: Arithmetic that makes you cringe
« Reply #279 on: 07 June, 2021, 02:08:23 pm »

A rate of knots would be acceleration.

Does the phrase not date back to the time when speed was determined by counting knots in a rope attached to a drag that was put out the stern of a ship? So that would be "rate of knots counted per 30 seconds."

Sam
I've done that.  With one of these. Bizarrely, for reasons I can't remember, the sand glass counts to 14 seconds. If I could be bothered I'd sit down and work it out. It probably means the knots in the line are x fathoms apart.
Rust never sleeps

ravenbait

  • Someone's imaginary friend
  • Pudge controls the weather.
    • Someone's imaginary friend
Re: Arithmetic that makes you cringe
« Reply #280 on: 07 June, 2021, 02:13:45 pm »

Probably for something like "per one turn of the small glass". It's probably OK to use if if you're still timing things other than eggs with sand-glasses, but most of us have moved on.

Lots of idioms remain in use after people no longer do the thing that coined the phrase.  We no longer use guns in naval warfare that have an accurate range best described as "near enough to piss on", but we still use the phrase "a long shot" to refer to something being a slim chance. And at least some of us know that the phrase is "toe the line" (not "tow the line"), and nobody is expected to line up barefoot on deck any more.

Quote
"Knots per hour" is just bloody ignorant (and/or BBC standard).

Completely agree.

Sam
https://ravenbait.com
"Created something? Hah! But that would be irresponsible! And unethical! I would never, ever make... more than one."

Re: Arithmetic that makes you cringe
« Reply #281 on: 07 June, 2021, 02:18:08 pm »

A rate of knots would be acceleration.

Does the phrase not date back to the time when speed was determined by counting knots in a rope attached to a drag that was put out the stern of a ship? So that would be "rate of knots counted per 30 seconds."

Sam
I've done that.  With one of these. Bizarrely, for reasons I can't remember, the sand glass counts to 14 seconds. If I could be bothered I'd sit down and work it out. It probably means the knots in the line are x fathoms apart.

Correct. Although the usual glass used was a 28 seconds one with the knots 7 fathoms apart.

That's assuming my memory is still functioning
“There is no point in using the word 'impossible' to describe something that has clearly happened.”
― Douglas Adams

Re: Arithmetic that makes you cringe
« Reply #282 on: 07 June, 2021, 02:19:10 pm »
Ooo. Possibly it was 28 seconds. It's a while since I last did this.
Rust never sleeps

Re: Arithmetic that makes you cringe
« Reply #283 on: 07 June, 2021, 02:28:05 pm »
I only ever did it once as an exercise in making a chip log in the sea scouts. I'm pretty sure the antique timer glass they gave us to work with was 28 secs.We had to build the rest with assorted bits of wood a long line and a measured fathom stick. It worked quite well when we tested it.
“There is no point in using the word 'impossible' to describe something that has clearly happened.”
― Douglas Adams