I'm surprised it didn't come up, but we do have a name for one arc minute which is nautical miles. So a knot is one nautical mile per hour. These are used because it does make things much easier to calculate in a map, and it's used not only in ships but also in aviation.
Okay, I'm confused though. The distance between arc minutes changes with latitude. So the answer to who's going faster depends on what latitude they are at. I mean if i do a spin around the pole at the north pole i went through 21600 arc minutes in about 3 seconds. So is a knot 1 nautical mile per hour, or is it 1 arc minute per hour?
The term "knots" originates from an old maritime practice. Sailors used a device called a log line to measure the speed of their ship. The log line was a rope with knots tied at regular intervals. They would throw the rope overboard and count the number of knots that passed through their hands in a specific amount of time, usually measured with a sandglass. This method allowed them to determine the ship's speed in nautical miles per hour, which is why we still use the term "knots" today
Exactly. And it wasn't until sufficiently accurate clocks were invented that they could accurately determine longitude. Neil should've talked about that a bit.
@bestsnow.. You are absolutely correct. A shame that Tyson didn't tie this into his explanation, (no pun intended). As opposed to a sextant, counting the knots in the log line informed the captain or navigator of their PRESENT speed in real time.
As someone who still knows how know to use a sextant, knots/nautical miles make sense as they are measurements of angle and it’s all spherical trigonometry.
@@GWNorth-db8vn because of the old machine tools limitations. With current CNC, tool paths can obey to any math. function (OK approximated to series of small vectors... ). Eg. boat propellers, turbine blades, wing profile .....
Aviation uses a complex mix of metric, imperial, and nautical measurements worldwide. We measure altitude in thousands of feet (imperial), speed in knots (as defined in this video), and temperature in Celsius (because you always want to know how close you are above or below the freezing point, ice on the wings is bad).
One aspect that can be confusing is the use of "mile" as a term. Whenever it is used in an aviation or maritime context, it refers to a nautical mile, not a statute mile.
@@PistonAvatarGuy Why should it al be metric? It works just fine the way it is, just the opposite of insane. No one (no one that matters, that is) gets confused by mix of units. You refuted your own assertion about what it should be with your observation about the horrifically painful tran$sition.
@@blindleader42 I suppose that's mostly true, it's just insane that we ended up with such a ridiculous mix of units in general. Everything should be metric and aircraft were new enough that metric units could have been easily used in aviation from the beginning.
@@blindleader42 The other issue is that we're likely to be stuck with those units in aviation for all of the foreseeable future, unless there's some sort of massive collapse. What happens if flying cars become a thing? Do people use US standard units on the ground and nautical units in the air? What happens if they fly outside of the US? Do they then switch to metric units? I suppose that everything will be automated by then, but do the designers of those flight systems then have to juggle three different measurement systems, or will they just program everything in metric and convert the units displayed to the operator of the aircraft? Seriously, it really is just nuts. Everything should be metric.
Fun fact: When the Brits and French were arguing over who got to be the prime meridian, the Brits ended up winning it in exchange for changing over to the Metric system (which they didn't for a long time and still haven't *fully* done)
I navigated in the US Navy in the late 70's. We had what we called "SatNav" back then primarily for position locating. We still did all of our course and speed and set and drift calculations by hand. A standard mile is 1760 yards. A nautical mile is 2000 yards. It made the math much easier. We also had to shoot the stars for I guess an emergency back up and to check our equipment to a point. Thanks for the great explanation and thank you for your time.
@@godsbeautifulflatearth You know, there are things called dictionaries where you could look up the meaning of a word such as level. But the fact that you think the UN logo is somehow evidence of something, tells me that reality just isn't in your wheelhouse.
@@godsbeautifulflateartherr ... sea level is measured relative to the geoid which ain't a flat surface. Also there is a tidal bulge on opposite sides of the world. Where do you think all that water runs off to during low tide if its level genius ?
Well, I don't really want to "yuk" your "yum", but this video is terrible. It has about 45 seconds of useful information wrapped 9 minutes of nonsense. So... pardon your hyperbole but there are hundreds of RUclips channels that are better than this.
A knot is one nautical mile per hour. The SI definition is one arcminute per hour along a line of longitude. The comes out to 2000 yards or 1850 meters and a little change. If you work out distances on a nautical chart, the utility of the nautical mile make distances easy to measure. Aviation uses many of the same terms (port, starboard, knot and even cockpit) because they are useful for navigation. Early aviators used charts in the same way mariners use them. The term has its origins in the age of sail where navigators would use rope with "knots" tied into it. And at the end of it is a weight. The knots are spaced at even intervals and when the rope was dropped into the water, the number of knots going in the water would be counted to get the ship's speed.
THIS! Ordinary "civilians" may find knots and nautical miles per hour unintuitive, but for navigation using basic tools and maps, they are far more convenient then constantly multiplying with some arbitrary coefficient.
@@justinrogers1807 The weight on the end isn't that heavy. Its enough to go into the water at a shallow depth. The line goes off a free spinning reel on the stern and pays out like if you were trawling for fish. The faster the forward motion through the water, the faster is pays out and the faster the knots move out into the water at a shallow angle. They w would count the knots as they left the stern If they had an idea of water current they were traveling through, they would perform a set and drift calculation to estimate speed over ground. and true course.
Do you know about François Joseph Paul de Grasse? That's Neil's ancestor. That's the reason the US isn't using the Metric System today. Do you know the story? Have you ever been Rochambeaued? I thought everybody in France knew about DeGrasse and Rochambeau. Everyone in the USA should know about it but we don't.
Originally knots were tied in a rope regular intervals and they would throw the rope over the side of the boat and count the number of knots that would pass in a certain length of time
That's the definition I always heard. I also have wondered if the sea voyage calculations had to compensate for currents when math-ing knots. Because the rope with knots really is only measuring how much water has flown past the ship. It cannot know what speed it's going relative to land by just using the knotted rope. I guess the sextant and other equipment came in to do those calculations. It also makes sense then to use in planes to measure airspeed. Because, for a plane, what the sensor on the fuselage can measure is likewise just the flow of air going past the plane. If it's windy, you can effectively stand still landspeed wise while still doing 50 knots in airspeed. Same thing when climbing or diving. Little landspeed but potentially lots of airspeed. My guess is that the archminute thing was retrofitted to make it more scientifically relevant than knotted ropes and a sailor kind of gut feeling the length of time before portable watches and clocks.
@@utube7930 you tie the knots before you throw it over the overboard. It's a very long rope too so you don't throw the whole rope over just the part that has the knots on
While we're on the subject of navigation, the story of John Harrison, who created the first chronometer accurate enough to be used when determining longitude on sea voyages, is absolutely fascinating.
Neil said early on the the video that although degrees were divided into minutes and seconds, there's no connection with time (apologies if I'm misquoting, I'm paraphrasing). It's true that there isn't an obvious relationship between degrees and time, but 360 degrees of longitude equates to a full day of 24 hours. Navigation by latitude and longitude requires an accurate clock. One reason why James Cook's maps were so accurate was because he had a new type of ship's clock, which enabled him to calculate longitude accurately. He was also an excellent navigator and cartographer as well. Observatories in cities like London (well, Greenwich) and Sydney had a ball on a pole on the roof which gave the crews on ships a visual indication of time by which to set their clocks. This was essential in order for them to navigate safely. I'm glad that someone else in the comments also mentioned the origin of "knots" originally being literal knots in a cord attached to a sea anchor fed over the stern. I was really surprised that these things weren't mentioned.
But why do we still use 360 degrees, 60 minutes an hour or degree and 60 seconds a minute. We do use the 10 base number system after all. Both in imperial and metric. Well we sometimes do. They tried to make metric time and degrees. 400 degrees on a circle, 100 minutes an hour and 100 seconds a minute. But it didn't catch on. It is because calculators is only about 50 years old. 60 is much easier to calculate with fractions. 100 is divided by 2, 4, 5, 10, 20, 25, 50. 60 is divided by 2, 3, 4, 5, 6, 10, 12, 15, 20, 30.
A knot is one mile per hour, but just not the mile measured on land. They did not mention the nautical mile which is the length of an arc-minute measured along a meridian. Sailors used to measure nautical miles using a drawing compass on the nautical chart. I learned this ancient technique to obtain my boat pilot licence before GPS was widely available.
Today navigation charts still provide degrees and minutes along the sides (if they are oriented North-up; most are). This means you can literally measure the distance in nautical miles without any instruments, using the minute markings on the sides (N/S, along the meridians). Sure is handy for estimating speeds and distances, when you can locate yourself on the chart by spotting coastal features, navigation markers or by GPS coordinates. If you understand this, with good visibility and a chart you can do 90% of coastal navigation without any instruments.
The modern international nautical mile has been set at exactly 1,852 meters (about 6,076.1 feet). In the UK, they commonly use a nautical mile equal to 6,080 feet.
That was awesome! I have been flying for decades and have randomly wondered why the heck we used Knots. I figured there was some reason like this, but knowing what it is now makes me very happy. As to the question of "why people are holding on to knots"....well, can you imagine the expense of converting every single aircraft and watercraft that uses instrumentation calibrated in Knots, ripping it all out and replacing it, reformulating every single procedure, like the thousands of instrument approaches in the world, re-training millions of people across more disciplines than I can name to do their job, or their hobby, without getting anyone killed... um yeah, knots are fine. Numbers on the dial match the numbers on the chart match the numbers on the instruments match the numbers everybody else is using. I hate all the random Imperial measurements as much as anyone, but changing it all to something new... (head explodes)
Rabbit: tie them together Piglet, can you tie a knot? Piglet: I cannot Rabbit: Uh, so you can knot Piglet: no, I cannot knot Rabbit: not knot? Pooh: who's there? Rabbit: Pooh!? Pooh: Pooh who?
Sailors would tie a rope to a log known as a "chip log" or "common log" shaped like a pie and knots were tied in the rope spaced 14.4 meters apart. They would throw the log overboard, flip an hourglass calibrated for 1 minute, and would count how many knots passed through their hand. Thus giving them the speed of the vessel. That's where knots came from. We use knots because charts are in nautical miles and it's far easier to calculate 1:1 rather than having to convert everything.
I love hearing Neil explain stuff like this ! I was waiting for the knotted rope to be mentioned. Once I had a history teacher who explained the lessons by adding interesting details and it was the only time history was enjoyable.
Great stuff, I had to learn all this in navigation training for lifeboat service here in the UK 🇬🇧 I’m actually quite surprised nobody mentioned the line (nobody says rope in nautical parlance…) that sailors would trail out behind the ship with knots tied at intervals, and how ever many knots were dragged out is how many knots the ship was making. Great chat as always fellas!
How anout when old wooden ships through a log over the back of the ship. The log had a rope wraprd about it with knots every so many feet. The number of knotd that rooled off the log during a certain amount of time determined the speed in knots per hour,
on any spheroid body, regardless of size, you can use a spherical coordinate system measured from the center of the sphere. on this sphere you have great circle (look it up if you dont know). 1 nautical mile is defined as 1 arc minute on that great circle. and speed is referred to in knots, is simply the number of arcminutes per unit of time (usually 1h). the fun part is that this is the same whether you navigate an object large as an orange, basketball, earth or the moon. you will allways use the same units of speed. so if your finger is tracing a path on an orange at the speed of 1 knot, it will have covered 1nautical mile on said orange after 1 hour. the actual distances is simply a matter of conversion from whatever circumference measured in your prefered unit your spheroid has. but the number of nautical miles on a great circle are always the same whether we are talking about jupiter or a basketball (360×60 = 21600nm). this is why its still the prefered unit of measurement in navigation. please be advised that the usual conversion factors used to convert to km or statue miles are only relevant on earth.
Some interesting points you left out: 1) When you solve problems in astronavigation, the answer comes out as the arc of a great circle - that is angular measure or arc-minutes. 2) When the french devised kilometers, the envisioned metric degrees, minutes and seconds. With 100 degrees in a quadrant (I.e. between equator and pole) and 100 minutes in a degree, there would be 10000 minutes rather than 5400 between equator and pole. Each of those 10000 minutes is defined as 1 kilometer - thus the solution to those angular navigation problems would come out directly in kilometers. Finally 3) why knots rather than nautical miles per hour. Sailors heaved the float at the end of a reel of line overboard and counted knots in the line running out while a sand glass ran out. The number of knots was the speed. Airline pilots use knots (speed not the line) too because the pre-1970s days of overseas flying involved astronavigation.
In ancient times, sailors used a method known as the "log of the chip." This technique involved casting a rope with a floating piece of wood (the log) into the sea. The rope had knots spaced at regular intervals, and sailors would count how many knots passed through their hands as a 30-second sandglass ran out. The number of knots counted corresponded to the vessel's speed in knots.
A few corrections. 1) a knot is the speed of one nautical miles per hour. That correlates with arcminutes in latitudes but only at the equator also in longitudes. As the distance of longitudes shrink towards the poles, the arcminute per hour doesn’t make much sense when discussing speed over ground. That’s why it is miles per hour. The measurement of knots was actually determined by throwing one end of a line into the water and counting the knots which passed through the hand. The length of the line and the distance of the knots were in tune with the mile, obviously, as one sixtieth of a mile, approx 34 yards or 31 meters. 2) why is this still in use in the age of GPS? Well, if you acquire a captains license you must know the traditional way of navigating. GPS could fail, the receiver as well as the satellites. Then you default back to maps and compasses, landmarks, solar altitude and exact time keeping.
Aliens absolutely did not have to know French and English history to know Science and Navigations on earth use a longitudal/lat system. They could have observed my 6th grade science class. We certainly were not taught the history of it, only how it works.
When travelling on land you can't go in a general direction straigth, so it is not usefull to use knots as you don't necesseraly change coordinates that much. In contrast, travelling large distances on sea or by plane, you actually go to other major longitutde/ latitude. Nice explanation ❤
I think that the reason knots and nautical miles are used in modern day navigation is because of the Mercator projection (which is very useful in navigation). When you have you basic distance unit same as arch minute of latitude, you have your scale always on the left side of the map and it changes depending on how far north or south is the area on the map. This makes it easy to measure distances on maps even if it's Mercator projection.
The one point not mentioned is that Knots and Nautical Miles relate to seafaring and aviation because in both cases you are separated from the terrain of earth's surface. Without having to adjust for uphill/downhill - nautical miles over land would be "as the crow flies". You no longer account for curves or the linear distance increase of upslope and downslope and are discussing linear distance (at least in segments).
I think the modern usefulness of the knot as a speed measurement is it's understood assumption that it is a speed relative to earth. If traveling against a 4km/h current it would be true to say you are traveling both 10km/h and 6km/h depending on your reference, and both those figures are useful in the context of sailing for example, whereas the knot does not have this reference ambiguity. It seems silly to use a different speed measurement when your primary experience is traveling on land, a perpetually fixed surface, but when the surface your traveling over is traveling itself, it is logical to make a distinction between relative and absolute speeds.
I was so excited. I really thought you were talking about ropes. There's so much physics in how and why some work better then others. As well the tensile strength of the fibers in rope. Could you make a video on that? I think it's cool. But admittedly not much to do with the common understanding of stars
In navigation of boats and aircraft, nautical miles are used. One nautical mile per hour is one knot. If you are using a sextant ( like we used to do) to work out your position, one minute of arc on the sextant equals one nautical mile! If you are calculating noon latitude with a sextant all the readings are done in degrees and seconds and the answer comes out in your latitude in degrees and seconds. The nautical mile and the knot relate directly to how we show latitude and longitude. One minute of longitude on a chart equals one nautical mile!
You do not use hard trigonometry navigating with paper charts, according to your course. It is much easier than so. Short distance in a straight line from A to B: Measure the distance with your divider (also called compass, not to confuse with the magnetic compass).Compare it to the scale on the side, not top or bottom, will give you the distance in archminutes or nautical miles (nm). If it is 12 nm and you go 4 kn, you're there in 3h. If 20 kn it is 0,6h or 36 minutes. Short distance in a not straight line from A to B: Set your divider on 1 nm with the scale on the side and "walk" your route. Now you have the distance. Long distance A to B on a large map. Now the projection of the map will be a problem. A straight line in reality is not a straight line on the map. Find the point in the middle of A and B, point C. Use a long flexible ruler through all 3 points. The curve is your "big circle", the shortest way from A to B on a sphere. The curved length is the distance. This seems obsolete skills in a modern digital world, but all electrical systems can fail. Then a paper chart and a magnet compass will work. Keeping those skills fresh kan save your life one day, if you go out sailing. 1 nm is 1852 m. So a good approximation is "a little less than 2k". So if you have a metric distance 20 km it is just over 10 nm, let's say about 12 nm. Divide in 2 and add some. If you have a nautical distance of 20 nm it is a little less than 40 km, let's say about 36 km. It isn't that hard, thou we do not have a unit close to 1 nm. Double and take some off.
Back in the day when I worked for the Weather Bureau (that's what it was called then), I worked with upper-air sounding. We measured wind speed in meters-per-second, which we converted to knots. One m/sec is almost equal to 2 knots. We didn't convert that way, we converted accurately. However, it always fascinated me. Both units were based on Earth measurements. If the meridian through Paris had been calculated more accurately (which was probably impossible at the time), then perhaps one m/sec would have been exactly 2 knots.
Lots of good comments here. The reason we still use knots in sail training is when you're on a boat and an emergency happens, you lose power. Guess what? You don't have those GPS coordinates anymore. You have to rely on your sights. Dead reckoning, the sun, moon, and stars, and any other tools you might have available. So the people that you are responsible for, or yourself, don't die. Besides, when you start teaching people about navigation and knots, it's confusing for them enough. You don't need to tell them it's an arc minute. It's a measurement of distance, and speed. After they figure that concept out, mixed with longitude and latitude, then you can start throwing wind speed, currents, and celestial navigation into the mix.
My dad was in the US Army, but he served on ships in the Army. He went from island to island in the Pacific serving in the Army. Anyway, when I was a kid, I asked my dad what a "knot" was and he said it was a "nautical mile per hour". I see now that he was very close.
Metric person here, but a pilot. Using knots with other imperial units somehow makes some mental mathematics on board much easier. An example: vertical speed for 3° descent for a runway? Ground speed in knots times 5 will give you your approximate descent rate in ft/min, which is the unit most airplanes have on the instrument (except gliders and some local airplanes in Europe).
That’s because you’re having to deal with relative speed of two vessels and where they are on the globe doesn’t matter. Approaching Rota or Sunoco Bay, knots are knots.
Here in Ontario, sales taxes add up to 15%, and prices are marked without tax. We're used to multiplying things by 1.15. Unfortunately, a nautical mile is 1.85 km, so that doesn't help at all.
Wait, if it's an arcminute of longitude, doesn't that mean that the speed changes depending on your latitude? Like 100km/h near the poles is like thousands of knots as you drive rings around a point, but half a knot around the equator? So it's not even a measurement of speed, but rather how quick you move across a degree-based coordinate system that not only changes depending on the direction of movement, but also where you are on those coordinates?
Pop Quiz Time! Convert 100 knots into km h? (let's see how the Americans fare)
This is completely unrelated, but do you think that we will, with enough advancements in technology, find that photons have mass?
185.2 kmh
186.7 km/h if considering the 24901 miles of circumference at a conversion rate of 1.62 km per mile. (Didn’t google this)
Maybe, maybe knot.
185.2 km/h because one arcminute is now defined as being exactly 1,852m instead of 1/60th of a degree.
I'm surprised it didn't come up, but we do have a name for one arc minute which is nautical miles. So a knot is one nautical mile per hour.
These are used because it does make things much easier to calculate in a map, and it's used not only in ships but also in aviation.
1.8 km in 3600 seconds, 0.5 m in s
Thanks!
An even 852 meters
Edit missed a 1 before 852
...and space re-entry points
Okay, I'm confused though. The distance between arc minutes changes with latitude. So the answer to who's going faster depends on what latitude they are at. I mean if i do a spin around the pole at the north pole i went through 21600 arc minutes in about 3 seconds.
So is a knot 1 nautical mile per hour, or is it 1 arc minute per hour?
The term "knots" originates from an old maritime practice. Sailors used a device called a log line to measure the speed of their ship. The log line was a rope with knots tied at regular intervals. They would throw the rope overboard and count the number of knots that passed through their hands in a specific amount of time, usually measured with a sandglass. This method allowed them to determine the ship's speed in nautical miles per hour, which is why we still use the term "knots" today
I'm not convinced "knots" (the rate of speed) was ever named for the knots in the log line. It's short for "nautical" (knotical) miles per hour.
Exactly. And it wasn't until sufficiently accurate clocks were invented that they could accurately determine longitude. Neil should've talked about that a bit.
8 fathoms between knots ( 48 feet, fathom is 6ft 6*8 48)
@bestsnow.. You are absolutely correct. A shame that Tyson didn't tie this into his explanation, (no pun intended). As opposed to a sextant, counting the knots in the log line informed the captain or navigator of their PRESENT speed in real time.
Disappointed this wasn't implemented into the video but what do ya do lol
Neil should have started by saying a minute of latitude is one nautical mile.
i feel the same and about to say this in the comment and saw you already said it.
They should stick to topics they are actually experts on. This was like a half baked conversation you would overhear in a bar.
Chuck Nice is hilarious and it's great how much he makes Neil chuckle
Chuck's the straight man but he's pretty smart himself.
Don’t you notice how exaggerated the laughter is? While you sit in silence…..
@@metricdeep8856Nope because he's genuinely funny. Have fun with that stick your sitting on
@@towlie9428 Easily entertained is a simple way to go through life. Scary for others……but appropriate for most.
I enjoy listening to Neil talk about subjects because he is so passionate about them, and it inspires me to learn new things too.
how can this astroturfing be stopped?
Yeah but just can't watch. The other guy (who ever is his).. SHUT UP!
As someone who still knows how know to use a sextant, knots/nautical miles make sense as they are measurements of angle and it’s all spherical trigonometry.
I never learned to use a sextant, but to an old-school machinist everything is made of circles and triangles.
That will help you learn how to use one. You should learn it'll help with navigation@@GWNorth-db8vn
@@GWNorth-db8vn because of the old machine tools limitations. With current CNC, tool paths can obey to any math. function (OK approximated to series of small vectors... ). Eg. boat propellers, turbine blades, wing profile .....
Aviation uses a complex mix of metric, imperial, and nautical measurements worldwide. We measure altitude in thousands of feet (imperial), speed in knots (as defined in this video), and temperature in Celsius (because you always want to know how close you are above or below the freezing point, ice on the wings is bad).
It's absolutely insane. It should all be metric, but that would be a horrifically painful transition.
One aspect that can be confusing is the use of "mile" as a term. Whenever it is used in an aviation or maritime context, it refers to a nautical mile, not a statute mile.
@@PistonAvatarGuy Why should it al be metric? It works just fine the way it is, just the opposite of insane. No one (no one that matters, that is) gets confused by mix of units.
You refuted your own assertion about what it should be with your observation about the horrifically painful tran$sition.
@@blindleader42 I suppose that's mostly true, it's just insane that we ended up with such a ridiculous mix of units in general. Everything should be metric and aircraft were new enough that metric units could have been easily used in aviation from the beginning.
@@blindleader42 The other issue is that we're likely to be stuck with those units in aviation for all of the foreseeable future, unless there's some sort of massive collapse. What happens if flying cars become a thing? Do people use US standard units on the ground and nautical units in the air? What happens if they fly outside of the US? Do they then switch to metric units? I suppose that everything will be automated by then, but do the designers of those flight systems then have to juggle three different measurement systems, or will they just program everything in metric and convert the units displayed to the operator of the aircraft? Seriously, it really is just nuts. Everything should be metric.
Fun fact: When the Brits and French were arguing over who got to be the prime meridian, the Brits ended up winning it in exchange for changing over to the Metric system (which they didn't for a long time and still haven't *fully* done)
Both Canada and Australia converted to metric currency to be compatible with metric USA.
Next question: wth is a stone? 😂
Meanwhile the US is happy to measure distances in football fields.
@@Vtarngpb Fourteen pounds.
I navigated in the US Navy in the late 70's. We had what we called "SatNav" back then primarily for position locating. We still did all of our course and speed and set and drift calculations by hand. A standard mile is 1760 yards. A nautical mile is 2000 yards. It made the math much easier. We also had to shoot the stars for I guess an emergency back up and to check our equipment to a point. Thanks for the great explanation and thank you for your time.
If you get off boarded, a swimmer's mile is 1600 yards
Also,
The Oceans are level, which means the Earth is Flat.
@@godsbeautifulflatearth If the earth was round all of the oceans would run to the edges, obviously.
@@godsbeautifulflatearth You know, there are things called dictionaries where you could look up the meaning of a word such as level. But the fact that you think the UN logo is somehow evidence of something, tells me that reality just isn't in your wheelhouse.
@@godsbeautifulflateartherr ... sea level is measured relative to the geoid which ain't a flat surface. Also there is a tidal bulge on opposite sides of the world. Where do you think all that water runs off to during low tide if its level genius ?
Knot what I expected! :D
This is the best youtube channel in the history of RUclips channels
Except for Neil constantly interrupting and talking over everyone
@@reeceguy3949 I adore Neil enough to overlook that..
Well, I don't really want to "yuk" your "yum", but this video is terrible. It has about 45 seconds of useful information wrapped 9 minutes of nonsense. So... pardon your hyperbole but there are hundreds of RUclips channels that are better than this.
@@tuckertucker1 Your politics is disturbing you
Yesssss fascinating
I love hearing neil talk about stuff hes so passionate about things so it makes me passionate to learn new stuff aswell
A knot is one nautical mile per hour. The SI definition is one arcminute per hour along a line of longitude. The comes out to 2000 yards or 1850 meters and a little change.
If you work out distances on a nautical chart, the utility of the nautical mile make distances easy to measure. Aviation uses many of the same terms (port, starboard, knot and even cockpit) because they are useful for navigation. Early aviators used charts in the same way mariners use them.
The term has its origins in the age of sail where navigators would use rope with "knots" tied into it. And at the end of it is a weight. The knots are spaced at even intervals and when the rope was dropped into the water, the number of knots going in the water would be counted to get the ship's speed.
"Arcminute per hour along a line of longitude" 👍
@@Ciubaruahh, that was not well described. I was thinking it changed depending on your latitude.
Why do they talk about fathoms as depth and not knots?? Knots are speed not depth and connot be both
THIS! Ordinary "civilians" may find knots and nautical miles per hour unintuitive, but for navigation using basic tools and maps, they are far more convenient then constantly multiplying with some arbitrary coefficient.
@@justinrogers1807 The weight on the end isn't that heavy. Its enough to go into the water at a shallow depth. The line goes off a free spinning reel on the stern and pays out like if you were trawling for fish. The faster the forward motion through the water, the faster is pays out and the faster the knots move out into the water at a shallow angle. They w would count the knots as they left the stern If they had an idea of water current they were traveling through, they would perform a set and drift calculation to estimate speed over ground. and true course.
🇫🇷 here, I love you too guys.
Do you know about François Joseph Paul de Grasse?
That's Neil's ancestor. That's the reason the US isn't using the Metric System today.
Do you know the story? Have you ever been Rochambeaued?
I thought everybody in France knew about DeGrasse and Rochambeau. Everyone in the USA should know about it but we don't.
Originally knots were tied in a rope regular intervals and they would throw the rope over the side of the boat and count the number of knots that would pass in a certain length of time
Without looking it up right now, this is what I always thought. Surprised Neil and Chuck didn't mention it.
That's the definition I always heard.
I also have wondered if the sea voyage calculations had to compensate for currents when math-ing knots. Because the rope with knots really is only measuring how much water has flown past the ship. It cannot know what speed it's going relative to land by just using the knotted rope. I guess the sextant and other equipment came in to do those calculations.
It also makes sense then to use in planes to measure airspeed. Because, for a plane, what the sensor on the fuselage can measure is likewise just the flow of air going past the plane. If it's windy, you can effectively stand still landspeed wise while still doing 50 knots in airspeed. Same thing when climbing or diving. Little landspeed but potentially lots of airspeed.
My guess is that the archminute thing was retrofitted to make it more scientifically relevant than knotted ropes and a sailor kind of gut feeling the length of time before portable watches and clocks.
I saw this in Black sails 😅
How do you tie a knot in a rope which is being thrown overboard?
@@utube7930 you tie the knots before you throw it over the overboard. It's a very long rope too so you don't throw the whole rope over just the part that has the knots on
I'm french and I love it when Chuck does its french impersonation!
While we're on the subject of navigation, the story of John Harrison, who created the first chronometer accurate enough to be used when determining longitude on sea voyages, is absolutely fascinating.
I'm surprised Neil didn't mention this and the chip log. That would've tied it all together.
@@bigredracingdog466
“One at a time”
I fricken love Chuck.
Neil said early on the the video that although degrees were divided into minutes and seconds, there's no connection with time (apologies if I'm misquoting, I'm paraphrasing). It's true that there isn't an obvious relationship between degrees and time, but 360 degrees of longitude equates to a full day of 24 hours. Navigation by latitude and longitude requires an accurate clock. One reason why James Cook's maps were so accurate was because he had a new type of ship's clock, which enabled him to calculate longitude accurately. He was also an excellent navigator and cartographer as well. Observatories in cities like London (well, Greenwich) and Sydney had a ball on a pole on the roof which gave the crews on ships a visual indication of time by which to set their clocks. This was essential in order for them to navigate safely. I'm glad that someone else in the comments also mentioned the origin of "knots" originally being literal knots in a cord attached to a sea anchor fed over the stern. I was really surprised that these things weren't mentioned.
But why do we still use 360 degrees, 60 minutes an hour or degree and 60 seconds a minute. We do use the 10 base number system after all. Both in imperial and metric. Well we sometimes do. They tried to make metric time and degrees. 400 degrees on a circle, 100 minutes an hour and 100 seconds a minute. But it didn't catch on. It is because calculators is only about 50 years old. 60 is much easier to calculate with fractions. 100 is divided by 2, 4, 5, 10, 20, 25, 50. 60 is divided by 2, 3, 4, 5, 6, 10, 12, 15, 20, 30.
A knot is one mile per hour, but just not the mile measured on land. They did not mention the nautical mile which is the length of an arc-minute measured along a meridian. Sailors used to measure nautical miles using a drawing compass on the nautical chart. I learned this ancient technique to obtain my boat pilot licence before GPS was widely available.
Today navigation charts still provide degrees and minutes along the sides (if they are oriented North-up; most are). This means you can literally measure the distance in nautical miles without any instruments, using the minute markings on the sides (N/S, along the meridians). Sure is handy for estimating speeds and distances, when you can locate yourself on the chart by spotting coastal features, navigation markers or by GPS coordinates. If you understand this, with good visibility and a chart you can do 90% of coastal navigation without any instruments.
Knotted up right now is crazyyy
ayo
So casually while he looks up at the sky
WILD 😂😂😂
What that mean
@@lhrmusic1It just sounds nasty 😂 super sus
The modern international nautical mile has been set at exactly 1,852 meters (about 6,076.1 feet). In the UK, they commonly use a nautical mile equal to 6,080 feet.
Please longer conversations we need it
That was awesome! I have been flying for decades and have randomly wondered why the heck we used Knots. I figured there was some reason like this, but knowing what it is now makes me very happy. As to the question of "why people are holding on to knots"....well, can you imagine the expense of converting every single aircraft and watercraft that uses instrumentation calibrated in Knots, ripping it all out and replacing it, reformulating every single procedure, like the thousands of instrument approaches in the world, re-training millions of people across more disciplines than I can name to do their job, or their hobby, without getting anyone killed... um yeah, knots are fine. Numbers on the dial match the numbers on the chart match the numbers on the instruments match the numbers everybody else is using. I hate all the random Imperial measurements as much as anyone, but changing it all to something new... (head explodes)
Rabbit: tie them together Piglet, can you tie a knot?
Piglet: I cannot
Rabbit: Uh, so you can knot
Piglet: no, I cannot knot
Rabbit: not knot?
Pooh: who's there?
Rabbit: Pooh!?
Pooh: Pooh who?
"no, i am Yu. he is Mi." 🤣
Sailors would tie a rope to a log known as a "chip log" or "common log" shaped like a pie and knots were tied in the rope spaced 14.4 meters apart. They would throw the log overboard, flip an hourglass calibrated for 1 minute, and would count how many knots passed through their hand. Thus giving them the speed of the vessel. That's where knots came from. We use knots because charts are in nautical miles and it's far easier to calculate 1:1 rather than having to convert everything.
finally, a video right up my alley: its all about knots!! 😭🤣🤣🤣
I know I’ve said this a whole bunch, but the editing on these 10 minute lessons makes the videos 10 times funnier than they already are on their own.
As a metric person, I was always estimating with 1 kn ~ 2 km/h, which is just about 10% off - less the error than with 1 kn ~ 1 mph.
i always love the way how they are "joking" with those "clever words".. XD
can watch these explainers all day !
This channel helps a simple mind like mine understand more science than I learned in school
Once again superb
I love hearing Neil explain stuff like this ! I was waiting for the knotted rope to be mentioned. Once I had a history teacher who explained the lessons by adding interesting details and it was the only time history was enjoyable.
And as French, we love you both!
I've needed this explanation my whole life
You two 😂 love ya both!
Great stuff, I had to learn all this in navigation training for lifeboat service here in the UK 🇬🇧 I’m actually quite surprised nobody mentioned the line (nobody says rope in nautical parlance…) that sailors would trail out behind the ship with knots tied at intervals, and how ever many knots were dragged out is how many knots the ship was making.
Great chat as always fellas!
How anout when old wooden ships through a log over the back of the ship. The log had a rope wraprd about it with knots every so many feet. The number of knotd that rooled off the log during a certain amount of time determined the speed in knots per hour,
That was always my understanding. If that is knot correct, where did...KNOT... come from as a unit.
on any spheroid body, regardless of size, you can use a spherical coordinate system measured from the center of the sphere. on this sphere you have great circle (look it up if you dont know). 1 nautical mile is defined as 1 arc minute on that great circle. and speed is referred to in knots, is simply the number of arcminutes per unit of time (usually 1h). the fun part is that this is the same whether you navigate an object large as an orange, basketball, earth or the moon. you will allways use the same units of speed. so if your finger is tracing a path on an orange at the speed of 1 knot, it will have covered 1nautical mile on said orange after 1 hour.
the actual distances is simply a matter of conversion from whatever circumference measured in your prefered unit your spheroid has. but the number of nautical miles on a great circle are always the same whether we are talking about jupiter or a basketball (360×60 = 21600nm). this is why its still the prefered unit of measurement in navigation. please be advised that the usual conversion factors used to convert to km or statue miles are only relevant on earth.
4:45 Someone in the animation department botched those latitude lines, looks like some flatearther snuck among you.
Those lines that are labeled "latitude"?
@@blindleader42 Yes, the latitude ones. Thanks to you, I've noticed that I wrote longitude instead of the correct word: latitude.
Chuck ius such an asset. He's a phenominally giy, so quick on his feet. Have been a fab since his radio days.
Some people are visual learners, Neil should have a blackboard to explain stuff like this
Everything to the metric system please ASAP
The sooner, the better
Okay…so what’s an Astro-knot?
Such a great video. Very educational. Way to go Chuck!
Some interesting points you left out: 1) When you solve problems in astronavigation, the answer comes out as the arc of a great circle - that is angular measure or arc-minutes. 2) When the french devised kilometers, the envisioned metric degrees, minutes and seconds. With 100 degrees in a quadrant (I.e. between equator and pole) and 100 minutes in a degree, there would be 10000 minutes rather than 5400 between equator and pole. Each of those 10000 minutes is defined as 1 kilometer - thus the solution to those angular navigation problems would come out directly in kilometers. Finally 3) why knots rather than nautical miles per hour. Sailors heaved the float at the end of a reel of line overboard and counted knots in the line running out while a sand glass ran out. The number of knots was the speed. Airline pilots use knots (speed not the line) too because the pre-1970s days of overseas flying involved astronavigation.
the knot situation is crazy
NASA stručnjak Gospodnetić?
Thanks , always a pleasure listening to you
Knot so long ago, in a another galaxy, there was . . .
In ancient times, sailors used a method known as the "log of the chip." This technique involved casting a rope with a floating piece of wood (the log) into the sea.
The rope had knots spaced at regular intervals, and sailors would count how many knots passed through their hands as a 30-second sandglass ran out.
The number of knots counted corresponded to the vessel's speed in knots.
“I’m knotted up right now! What are you talking about?”
A few corrections.
1) a knot is the speed of one nautical miles per hour. That correlates with arcminutes in latitudes but only at the equator also in longitudes. As the distance of longitudes shrink towards the poles, the arcminute per hour doesn’t make much sense when discussing speed over ground. That’s why it is miles per hour. The measurement of knots was actually determined by throwing one end of a line into the water and counting the knots which passed through the hand. The length of the line and the distance of the knots were in tune with the mile, obviously, as one sixtieth of a mile, approx 34 yards or 31 meters.
2) why is this still in use in the age of GPS? Well, if you acquire a captains license you must know the traditional way of navigating. GPS could fail, the receiver as well as the satellites. Then you default back to maps and compasses, landmarks, solar altitude and exact time keeping.
Aliens absolutely did not have to know French and English history to know Science and Navigations on earth use a longitudal/lat system. They could have observed my 6th grade science class. We certainly were not taught the history of it, only how it works.
When travelling on land you can't go in a general direction straigth, so it is not usefull to use knots as you don't necesseraly change coordinates that much. In contrast, travelling large distances on sea or by plane, you actually go to other major longitutde/ latitude. Nice explanation ❤
Christ is king!
REJECT THE WHITE MAN'S GOD
You guys do a fantastic show thank you so much
wow the people who worked all this out..
i love it.. 🙂
I think that the reason knots and nautical miles are used in modern day navigation is because of the Mercator projection (which is very useful in navigation). When you have you basic distance unit same as arch minute of latitude, you have your scale always on the left side of the map and it changes depending on how far north or south is the area on the map. This makes it easy to measure distances on maps even if it's Mercator projection.
"So, what is a knot? Just to be sure I'm still an educator"
"Aeehgr ehhmmm daddad..."
/ Neil's face zoomed in 🤣🤣🤣
Always a pleasure gentlemen, greetings and likes always.
From South Africa
I love Chuck and Neil interactions! :)
And I learned something new today! (or ancient?)
The one point not mentioned is that Knots and Nautical Miles relate to seafaring and aviation because in both cases you are separated from the terrain of earth's surface. Without having to adjust for uphill/downhill - nautical miles over land would be "as the crow flies". You no longer account for curves or the linear distance increase of upslope and downslope and are discussing linear distance (at least in segments).
I think the modern usefulness of the knot as a speed measurement is it's understood assumption that it is a speed relative to earth. If traveling against a 4km/h current it would be true to say you are traveling both 10km/h and 6km/h depending on your reference, and both those figures are useful in the context of sailing for example, whereas the knot does not have this reference ambiguity. It seems silly to use a different speed measurement when your primary experience is traveling on land, a perpetually fixed surface, but when the surface your traveling over is traveling itself, it is logical to make a distinction between relative and absolute speeds.
Thank you I’ve always wondered.
Nothing is better than kicking back with my black beer and watching your new video 🫶🏾 I truly enjoy and love it.
Thank you Neil …
❤
I was so excited. I really thought you were talking about ropes. There's so much physics in how and why some work better then others. As well the tensile strength of the fibers in rope. Could you make a video on that? I think it's cool. But admittedly not much to do with the common understanding of stars
As a merchant mariner, I would like this as well.
In navigation of boats and aircraft, nautical miles are used.
One nautical mile per hour is one knot.
If you are using a sextant ( like we used to do) to work out your position, one minute of arc on the sextant equals one nautical mile!
If you are calculating noon latitude with a sextant all the readings are done in degrees and seconds and the answer comes out in your latitude in degrees and seconds.
The nautical mile and the knot relate directly to how we show latitude and longitude.
One minute of longitude on a chart equals one nautical mile!
You do not use hard trigonometry navigating with paper charts, according to your course. It is much easier than so.
Short distance in a straight line from A to B:
Measure the distance with your divider (also called compass, not to confuse with the magnetic compass).Compare it to the scale on the side, not top or bottom, will give you the distance in archminutes or nautical miles (nm). If it is 12 nm and you go 4 kn, you're there in 3h. If 20 kn it is 0,6h or 36 minutes.
Short distance in a not straight line from A to B:
Set your divider on 1 nm with the scale on the side and "walk" your route. Now you have the distance.
Long distance A to B on a large map.
Now the projection of the map will be a problem. A straight line in reality is not a straight line on the map. Find the point in the middle of A and B, point C. Use a long flexible ruler through all 3 points. The curve is your "big circle", the shortest way from A to B on a sphere. The curved length is the distance.
This seems obsolete skills in a modern digital world, but all electrical systems can fail. Then a paper chart and a magnet compass will work. Keeping those skills fresh kan save your life one day, if you go out sailing.
1 nm is 1852 m. So a good approximation is "a little less than 2k". So if you have a metric distance 20 km it is just over 10 nm, let's say about 12 nm. Divide in 2 and add some. If you have a nautical distance of 20 nm it is a little less than 40 km, let's say about 36 km. It isn't that hard, thou we do not have a unit close to 1 nm. Double and take some off.
With knots (nautical miles) is easier to make measurements and calculations on the chart, that’s why it sticks.
If you measure east - west that only works at equator.
I just realized when they were talking that the system is "knottical" (nautical). Anyway, this was another fun episode.
Learned something, thanks!
Chuck's explanation! 😄
Always loving these explainers 😅😂....I love learning 😢😂
The way I learnt it was a nautical mile (knot) is 15% longer than a land mile.
no one cares. out of the 904 comments, no one is gonna read your 1 comment
@@infiniteworfare5089I read his comment, you are wrong, and needlessly cruel. I hope you find happiness
@@wc8246 wow ;( . btw wc, do you believe that science is becoming dangerous with time?
The question posed in the title wasn't answered, why do we still use knots !! great content as always, I really enjoy the show !
Thank you!
Back in the day when I worked for the Weather Bureau (that's what it was called then), I worked with upper-air sounding. We measured wind speed in meters-per-second, which we converted to knots. One m/sec is almost equal to 2 knots. We didn't convert that way, we converted accurately. However, it always fascinated me. Both units were based on Earth measurements. If the meridian through Paris had been calculated more accurately (which was probably impossible at the time), then perhaps one m/sec would have been exactly 2 knots.
oh geez. i never saw the movie close encounters. that scene of using musical tones to communicate seemed excellent. i gotta watch that
This one made me laugh out loud - esp. Chuck's definition of a knot.
I know! He did "use all the words"!
@@EricRoss57 Not so much a word salad as a word compost heap.
Excellent explanation, as well as, quite entertaining!
CHUCK IS BACK?!?!
Lots of good comments here.
The reason we still use knots in sail training is when you're on a boat and an emergency happens, you lose power. Guess what? You don't have those GPS coordinates anymore. You have to rely on your sights. Dead reckoning, the sun, moon, and stars, and any other tools you might have available. So the people that you are responsible for, or yourself, don't die.
Besides, when you start teaching people about navigation and knots, it's confusing for them enough. You don't need to tell them it's an arc minute. It's a measurement of distance, and speed. After they figure that concept out, mixed with longitude and latitude, then you can start throwing wind speed, currents, and celestial navigation into the mix.
And thank you by ending the show with the Jack Horkheimer quote of keep looking up. That is a tender thought.
Had to knot so much earlier, it’s crazy this is on my feed now
Neil and Chuck, y'all rock! ❤😂 Peace 🤘
My dad was in the US Army, but he served on ships in the Army. He went from island to island in the Pacific serving in the Army. Anyway, when I was a kid, I asked my dad what a "knot" was and he said it was a "nautical mile per hour". I see now that he was very close.
I concur with his lordship, the Honorable Charles Nice's assessment of the French.
Metric person here, but a pilot. Using knots with other imperial units somehow makes some mental mathematics on board much easier. An example: vertical speed for 3° descent for a runway? Ground speed in knots times 5 will give you your approximate descent rate in ft/min, which is the unit most airplanes have on the instrument (except gliders and some local airplanes in Europe).
This blew my mind
But in practical terms, doing calculations for maneuvering board, knots are just speed per hour no matter what your lat, long.
That’s because you’re having to deal with relative speed of two vessels and where they are on the globe doesn’t matter. Approaching Rota or Sunoco Bay, knots are knots.
I love your intro graphic/logo!
This was fascinating. I thought it might be an acronym ending in 'on the sea'. Now I know better!
Love this. Appreciate you guys❤
How do you divide the degrees?
Chuck: one at a time 😂😂
That's my answer, still even after Tysons explanations
Thanks Y’all
I would love to have lunch with these two men! Can't imaging how obscure the conversations would be.
Here in Ontario, sales taxes add up to 15%, and prices are marked without tax. We're used to multiplying things by 1.15. Unfortunately, a nautical mile is 1.85 km, so that doesn't help at all.
Wait, if it's an arcminute of longitude, doesn't that mean that the speed changes depending on your latitude? Like 100km/h near the poles is like thousands of knots as you drive rings around a point, but half a knot around the equator? So it's not even a measurement of speed, but rather how quick you move across a degree-based coordinate system that not only changes depending on the direction of movement, but also where you are on those coordinates?