Talk:Knot (speed)

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knot is a unit of speed, not velocity. Speed is a scalar (distance over time) while velocity is a vector (displacement (direction vector) over time). A knot is obviously the former. Stewart Adcock 18:42, 20 Nov 2003 (UTC)

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I'm changing the name of the article to "Knot (speed)" from "Knot (nautical)", because the unit is used not only for nautical things but also in meteorology and aviation. GrahamN 15:12, 1 Apr 2004 (UTC)

How about nautical mile per hour? –radiojon 03:09, 2004 Apr 2 (UTC)

The thing is known as a "knot", not a "nautical mile per hour". What's wrong with "Knot (speed)"? GrahamN 16:38, 2 Apr 2004 (UTC)

Contents 1 Wrong data? 2 Locale 3 Examples 4 Text cut and pasted from other site 5 Why? 6 Velocity made good? 7 Still do not understand

[edit] Wrong data?

I've done some calculations, and unless I'm mistaken 1 knot equals 1.32 miles per hour, not 1.15 as the article states. Furthermore, I believe it would be more useful for international users if the equivalent speed in kilometers per hour (kph) was added, since it's a more familiar scale of speed, with which most people around the world can relate (not the case of miles per hour or metres per second). Regards, Redux 12:20, 14 Sep 2004 (UTC)

• My caclulations agree with the article. (If you follow the link on the number in the article, you'll see that Google's calculations agree as well.) But as for kph, that's easy: 1852 m/h = 1.852 km/h! Isn't the metric system nifty? -- Toby Bartels 05:33, 14 Oct 2004 (UTC)

You were right about the knot/mph ratio, I had miscalculated. I'd remove the "precisely" after the kph conversion though, since 1.852 is a round up (the actual precise number being 1.851999985024). I'm glad to have been of assistance in the m/h v. km/h thing. Regards, Redux 20:06, 11 Dec 2004 (UTC)

Redux talked about 'metres per second', not 'per hour'. And timekeeping, alas, isn't that simple in the metric system. It's not decimal, but more like duodecimal or 60-base. But the article now already gives km/h, so what am I on about? DirkvdM 10:26, 21 August 2005 (UTC)

Though I'm neither a mathematician nor a sailor, I'd consider replacing the term "roughly" as the characterization of the conversions from knots to statutory miles per hour, at least. The reason? Because, worked out to six decimal places as it is, a difference of one digit in the last decimal place (e.g., 1.150780 mph instead of the stated 1.150779 mph) amounts to traveling 0.0634 inches (1.61 mm) more or less over one hour. To me, "roughly" in this context indicates a coarse measure. However, wouldn't the differences here be really difficult to measure in any practical situation. Wouldn't the phrase "almost precisely" be a better substitute? Am I missing something here? Anoneditor 22:58, 4 November 2006 (UTC)

I think the correct mathematical phrase is "is approximately equal to". The reason for including the phrase is to highlight the fact that one of the conversions (to 1.852 kilometres per hour) is exact and by definition; the others are only true to the accuracy shown. I agree that the current version is 'sub-optimal', but what do people think is the best way to express this? Maybe two lists, one with only that conversion in it? Maybe change the phrase introducing the current list, and keep the bold print just for that one? --Nigelj 10:10, 5 November 2006 (UTC)

OK, how about this?

== Conversions ==

1 (international) knot is exactly equal to 1.852 kilometres per hour, and is approximately equal to the following:

• 101.268591 feet/minute
• 1.687810 feet/second
• 0.5144444 metres per second
• 1.150779 mile (statute)/hour (mph)
• 0.99936 Admiralty knot

Looks fine to me. So good in fact that I have added it to the article. --Nigelj 21:40, 5 November 2006 (UTC)

[edit] Locale

where is the knot unit used? is it used outside of USA as well? Xah Lee 03:49, 2004 Oct 12 (UTC)

I'd guess that the knot is usually used at sea. ;-) Yes, it is widely used outside the US. It is used in Britain at least. Stewart Adcock 00:20, 15 Oct 2004 (UTC)

Knots are used around thw world for maritime and aviation purposes, like GMT is. Dolive21 11:34, 2 February 2006 (UTC)

[edit] Examples

I looked here to see what typical speeds of ships are. The Stad Amsterdam is supposed to be very fast with 16 knots. How fast is that for a tall ship? And what are typical speeds of other types of boats/ships? DirkvdM 10:26, 21 August 2005 (UTC)

For a clipper, that's fast. That's also a little faster than many naval ships typically go, but I know that Nimitz class carriers are capable of around 30 knots. BioTube 01:17, 24 September 2006 (UTC)

[edit] Text cut and pasted from other site

I just removed a big chunk of text which was added by user 69.58.224.12. This was because it was just cut and pasted, probably from this site. --Spondoolicks 09:43, 23 August 2006 (UTC)

Thanks. I've also now removed the 'CleanUp' tag that had been added because of this strange text. --Nigelj 18:51, 23 August 2006 (UTC)

[edit] Why?

Why do they still use inferior knots and not, m/s or km/h? --- Unsigned comment.

Read second paragraph of the "Discussion" section in article. --- Safemariner 14:56, 30 December 2006 (UTC)

[edit] Velocity made good?

Could someone confirm that velocity made good really refers to speed over ground. I am a ship science student, I have only come across velocity made good as meaning the velocity vector either to windward or toward some reference point (typically toward a waypoint in GPS's). —The preceding unsigned comment was added by 152.78.254.72 (talk) 19:03, 13 March 2007 (UTC).

It can be more complicated for a sailing boat: You might be beating hard on the wind, and so unable to sail directly towards your waypoint: VMG towards the waypoint is very different to SOG in that case. --Nigelj 20:19, 13 March 2007 (UTC)

[edit] Still do not understand

I looked this up for the origin of the term "Knot", which I still do not understand. —The preceding unsigned comment was added by 71.218.13.153 (talk) 03:56, 7 April 2007 (UTC).