@@David0lyle Yes . Various ways of knowing what the compass is off by at various points. Most hunters learn that charts maps show what the compass deviation is at various points . That same system is used at sea.
You simplify the compass a bit there is more to them than the quadrant balls or Kelvin balls as you call them. First of all you will find fixed magnets underneath the compass. This is to compensate for the fixed magnetism in the ship. Start by putting the vessel on a north - south and an east - west course and add or remove magnet rods to minimize the deviation. Then you put the vessel on one of the quadrant courses and adjust the Kelvin balls to minimize the deviation. The Kelvin balls compensate for the fluctuating magnetism in the vessel . Do that on several quadrant courses and position the balls so that you get the most favorable deviation on all of these courses. Then it is time to add the Flinders bars. There is a tubing in the front or in the back of the compass that you fill with soft iron bars. This is to compensate for the magnetic error that is caused by the change in latitude . This is because the angle of the magnetic field will change with latitude. The last thing you do is to adjust the length of the string that holds a magnet that is dangling underneath the compass. This magnet is to compensate for the change in the magnetic field when the ship is rolling. For those that wants to be really nerdy they can calculate each of the magnetic components by using Archibal Smith’s quotation.
Thanks for that! With your knowledge of the subject, I wonder if you could think of a way to partially compensate for a *changing* magnetic field on the ship, one that changes faster than you manually recalibrate. Consider the shop were powered by two large electric motors. (Maybe it's a submarine, so it needs propulsion without combustion). The magnetic fields from the motor power system would be changing all the time. Any ideas on how to reduce the error that would cause in the compass?
@@senseisecurityschool9337 There is no quick fix to the problem that is why they do or at least they did deviation checks on every watch if they could. The observation is logged and in addition they have a poster on the wall where they can read the expected deviation for this particular ship. The poster is usually replaced every year when somebody (usually an expert) calibrate the compass. It is not too difficult but you have to follow certain procedures. Then you have special cases for instance if a ship has left a repair yard after extensive metal works. Then the compass will usually be recalibrated to compensate for the new magnetic field that has been created. A more difficult case is it the vessel has loaded a cargo of scrap metal because that will interfere the magnetic compass strongly and it will alter as the vessel sails along to the discharge port. The only thing you can do is observe the deviation and take it into account when you plan the course the ship should sail. In the childhood of the submarines they quickly discovered that magnetic compasses were useless on this type of vessel, specially when submerged. This problem was solved by a German named Herman Anchutz that invented the gyro compass. He founded his company in 1905 and started production in 1908. The company exists even these days.
@@runedahl1477 Thanks for that. What I may need to do is compare the gyro with the magnetometer and then not only blend the the two readings, but ALSO predict that the compass reading may continue to be offset by a similar amount for a short time in the future. Similarly with the GPS. If the GPS is saying we're going north and the compass is reading 15° off north, I can predict that in the short term the compass may continue to be off by about 15°. (Cheap gyro isn't accurate over periods of more than a few seconds, but I could measure the compass offset vs the gyro and maybe that will tend to stay stable slightly longer).
@@senseisecurityschool9337 Magnetic compasses and gyro compasses are two different things. The magnetic compass is drawn towards the magnetic north and south poles while the gyros points at the geographic poles. The magnetic North Pole lies north of Canada at the moment but the magnetic poles are moving. To calculate what course you have to steer you start with the course you plot in the chart. This is called the “right course”. Then you compensate for the variation between the magnetic pole and the geographical pole and you get the “Magnetic course”. This variation can be read in the charts. On the “magnetic course” you compensate for the local magnetism in the ship, also called deviation and you get the “Compass Course “ which is the one you have to steer after on the magnetic compass. Gyros are different. A spinning gyroscope will point its axis at a fixed point in space. If you monitor a gyroscope you will notice that after one hour it has lifted its axis and is pointing 15 degrees East compared to where it pointed when you started it. In the early gyros they added mercury as a counterweight so when the axis lifted the weight of the mercury would force the gyroscope back into a horizontal position. The reason why the axis lifts 15 degrees is the rotation of the earth. 360 degrees divided by 24 is 15 degrees. Anschutz used two spheres with a gyroscope inside and linked to each other and floating in a glycol liquid at a temperature of 54 degrees centigrade if I remember correctly. At that temperature the flotation of the spheres are neutral. If you want to get really nerdy you will have to compensate for the latitude and the speed of the ship through the water and compensate this with the right course and you get the gyro course which you will have to steer on the gyrocompass. The gyro error can easily be calculated when you know the latitude and the speed and in more modern gyroscope this is calculated automatically. The GPS is something completely different where the receiver onboard is a small computer that receives data from a number of satellites in fixed positions around the equator and based on these signals it can calculate its own position. It knows exactly where these satellites a located and can based on these information calculate where it is. With a few updates it is easy for it to calculate where it is heading. The first type of satellites for position finding went in polar orbits and sent out constantly information about its location. Based on the Doppler effect the ships could compute where it was relatively to the satellite. When you got two or more observations you would know you position similar to that of astronomical observations. Now these days there are much cheaper solutions when it comes to compasses for hobby use. They are small, relatively cheap and can be calibrated electronically. That is probably ok as long as you only are in coastal waters. Besides these boats are usually made out of fiberglass (Tupperware) or wood that don’t affect the magnetic fields in the boats. Besides if they have a gps backup they are fairly safe. However if I were to go on an ocean crossing I would invest in more professional equipment.
@@senseisecurityschool9337 The electrical wires or cables leading to and from equipment are run in parallel, right next to each other, so that the magnetic field from each cancels out the others at a distance of about 10x the distance between the axes of the wires/cables.
I've always appreciated the nickname Iron Mike. Makes ya feel good. Like some kind of tough guy or something. Cuz, like... I'm just a big nerd. Please don't hit me. I'll probably die. 😅
@@dbmail545 A "whiskey" compass in a small aircraft has small, internal, adjustable magnets. There is a procedure termed "swinging the compass" where the aircraft is rotated about a "compass rose" and the magnets are adjusted to get the truest overall reading from the compass over all headings. A small card is then attached indicating the error for different headings.
The origin of the Plimsoll mark is quite easy to explain. Lord Plimsoll is probably the person that singlehanded have done most for safety at sea. He noted that a number of ships sunk because they were overloaded and pressed forward a law in the English parliament that required all cargo ships to have a mark on the ship side to indicate the maximum weight they were allowed to load. Ironically is that the same ships that Plimsoll was after is the ones that is referred to as Plimsollers. In other words the worts wrecks. In the years after Plimsoll the maximum allowable weight has been modified a little. You have now Summer-draft,Winter-draft,Freshwater,winter Atlantic and tropical draft. There are guidelines to tell you where and when these requirements apply and if you break them you are in for a heavy fine.
So... How do you know how to set the distance at which the Magnetic Cast Iron Balls... That would even change with the Cargo you are carrying and what Ammunition (if they were Cannon Balls) you had aboard and how much of it.... I'm probably over thinking things....
Good idea for video and good commentary. However the clips and your pronunciation of non-ferrous make it seem much less serious. I strongly suggest you reproduce this clip and run it by a few people. This could be a really good video vs. one that I stopped part way through
I loved all the clips. This was a well put together presentation.
Glad you enjoyed it! Our editor is easily amused when it comes to movie references
Those balls are moved in and out to adjust for magnetic deviation.
But wouldn’t you have to know where you were to make that adjustments?
@@David0lyle Yes . Various ways of knowing what the compass is off by at various points. Most hunters learn that charts maps show what the compass deviation is at various points . That same system is used at sea.
Oh crap it gets funnyer😂😂❤😂in an out an brass around it😂😂😮
My balls do the same. Except they’re automatic.
Thanks. It comforts me to know there are so many people throughout history, all over the world, who are smart enough to figure this stuff out!
This was fun and informative…. Thank you!
Genius, who would’ve thought putting a couple of huge iron balls beside the compass to get a true reading,
So, is Kelvin missing his balls? Sorry, just could not resist, no self-control.
It's okay, I immediately chuckled when I read "Kelvin's Balls". How do we know where we're going? Idk ask Kelvin to check his balls.
Go to your room
You said it so we don't have to. Kudos.
@@harveysmith100: 😄😂🤣
I'm absolutely ferrious that anyone would even make these rude jokes.
Lol "everything looks like the ocean" that made me laugh.
I like to have a sextant, a clock, and a chart of the star positions as back up. I have a 14 foot flat bottom boat.
😂
*chronograph
You simplify the compass a bit there is more to them than the quadrant balls or Kelvin balls as you call them. First of all you will find fixed magnets underneath the compass. This is to compensate for the fixed magnetism in the ship. Start by putting the vessel on a north - south and an east - west course and add or remove magnet rods to minimize the deviation. Then you put the vessel on one of the quadrant courses and adjust the Kelvin balls to minimize the deviation. The Kelvin balls compensate for the fluctuating magnetism in the vessel . Do that on several quadrant courses and position the balls so that you get the most favorable deviation on all of these courses. Then it is time to add the Flinders bars. There is a tubing in the front or in the back of the compass that you fill with soft iron bars. This is to compensate for the magnetic error that is caused by the change in latitude . This is because the angle of the magnetic field will change with latitude. The last thing you do is to adjust the length of the string that holds a magnet that is dangling underneath the compass. This magnet is to compensate for the change in the magnetic field when the ship is rolling.
For those that wants to be really nerdy they can calculate each of the magnetic components by using Archibal Smith’s quotation.
Thanks for that!
With your knowledge of the subject, I wonder if you could think of a way to partially compensate for a *changing* magnetic field on the ship, one that changes faster than you manually recalibrate. Consider the shop were powered by two large electric motors. (Maybe it's a submarine, so it needs propulsion without combustion). The magnetic fields from the motor power system would be changing all the time.
Any ideas on how to reduce the error that would cause in the compass?
@@senseisecurityschool9337 There is no quick fix to the problem that is why they do or at least they did deviation checks on every watch if they could. The observation is logged and in addition they have a poster on the wall where they can read the expected deviation for this particular ship. The poster is usually replaced every year when somebody (usually an expert) calibrate the compass. It is not too difficult but you have to follow certain procedures. Then you have special cases for instance if a ship has left a repair yard after extensive metal works.
Then the compass will usually be recalibrated to compensate for the new magnetic field that has been created. A more difficult case is it the vessel has loaded a cargo of scrap metal because that will interfere the magnetic compass strongly and it will alter as the vessel sails along to the discharge port. The only thing you can do is observe the deviation and take it into account when you plan the course the ship should sail. In the childhood of the submarines they quickly discovered that magnetic compasses were useless on this type of vessel, specially when submerged. This problem was solved by a German named Herman Anchutz that invented the gyro compass. He founded his company in 1905 and started production in 1908. The company exists even these days.
@@runedahl1477
Thanks for that. What I may need to do is compare the gyro with the magnetometer and then not only blend the the two readings, but ALSO predict that the compass reading may continue to be offset by a similar amount for a short time in the future.
Similarly with the GPS. If the GPS is saying we're going north and the compass is reading 15° off north, I can predict that in the short term the compass may continue to be off by about 15°.
(Cheap gyro isn't accurate over periods of more than a few seconds, but I could measure the compass offset vs the gyro and maybe that will tend to stay stable slightly longer).
@@senseisecurityschool9337 Magnetic compasses and gyro compasses are two different things. The magnetic compass is drawn towards the magnetic north and south poles while the gyros points at the geographic poles. The magnetic North Pole lies north of Canada at the moment but the magnetic poles are moving. To calculate what course you have to steer you start with the course you plot in the chart. This is called the “right course”. Then you compensate for the variation between the magnetic pole and the geographical pole and you get the “Magnetic course”.
This variation can be read in the charts. On the “magnetic course” you compensate for the local magnetism in the ship, also called deviation and you get the “Compass Course “ which is the one you have to steer after on the magnetic compass. Gyros are different. A spinning gyroscope will point its axis at a fixed point in space. If you monitor a gyroscope you will notice that after one hour it has lifted its axis and is pointing 15 degrees East compared to where it pointed when you started it. In the early gyros they added mercury as a counterweight so when the axis lifted the weight of the mercury would force the gyroscope back into a horizontal position. The reason why the axis lifts 15 degrees is the rotation of the earth. 360 degrees divided by 24 is 15 degrees.
Anschutz used two spheres with a gyroscope inside and linked to each other and floating in a glycol liquid at a temperature of 54 degrees centigrade if I remember correctly. At that temperature the flotation of the spheres are neutral. If you want to get really nerdy you will have to compensate for the latitude and the speed of the ship through the water and compensate this with the right course and you get the gyro course which you will have to steer on the gyrocompass. The gyro error can easily be calculated when you know the latitude and the speed and in more modern gyroscope this is calculated automatically. The GPS is something completely different where the receiver onboard is a small computer that receives data from a number of satellites in fixed positions around the equator and based on these signals it can calculate its own position. It knows exactly where these satellites a located and can based on these information calculate where it is. With a few updates it is easy for it to calculate where it is heading. The first type of satellites for position finding went in polar orbits and sent out constantly information about its location. Based on the Doppler effect the ships could compute where it was relatively to the satellite. When you got two or more observations you would know you position similar to that of astronomical observations. Now these days there are much cheaper solutions when it comes to compasses for hobby use. They are small, relatively cheap and can be calibrated electronically. That is probably ok as long as you only are in coastal waters. Besides these boats are usually made out of fiberglass (Tupperware) or wood that don’t affect the magnetic fields in the boats. Besides if they have a gps backup they are fairly safe. However if I were to go on an ocean crossing I would invest in more professional equipment.
@@senseisecurityschool9337
The electrical wires or cables leading to and from equipment are run in parallel, right next to each other, so that the magnetic field from each cancels out the others at a distance of about 10x the distance between the axes of the wires/cables.
Thank you, that took some balls...
This is great - never knew. Thanks.
Thank YOU for watching
You could talk about the turns done once a day to verify the magnetic and gyro compasses perform the same and aren't faulty.
Little known fact: the balls on the USS Johnson were bigger than all others.
Interesting. Thanks.
Thanks!
Thanks for watching!
Excellent ❤😊
Thank you!
Fun video
Called the ships balls.
Balls of steel man. Why to hold your ground when you're wrong. Ferryus😅
Very good video. Ferrieuoieus.
@@carpballet: 😃😄😆😂🤣
Never knew how this was done
Great movie that, a classic: Ferrious Bueller’s Day Off. 😈
The magnetic compass on a ship is periodically checked by a certificated Compass Adjuster
had someone use the phrase "ferronious" to describe ferrous materials today lol
@zulu3006 : 😄😆😂🤣 His name's Elijah and he's harmless. Just don't let him be responsible for safety. (See Safety Zone videos)
Waaaaay back: Lodestone
Science!
sort of.....
Brass is indeed a nerafious metal
Wow!
Could do without the clips; takes away from what is otherwise an interesting lesson.
@@Craptastic760: Trying out different formats to see what works and what doesn't. Thank you for the honest and POLITE feedback. 🙂 Greatly helps.
@@usskidd661 Apparently, some people like the pop culture clips interjected. Not my preference but I did enjoy your video so keep at it.
@@Craptastic760: Thanks!
I worked on a fishing boat where the captain called them Iron Mikes. ?
@standorf958 : There seems to be a million nicknames for them.
I've always appreciated the nickname Iron Mike.
Makes ya feel good. Like some kind of tough guy or something.
Cuz, like... I'm just a big nerd. Please don't hit me. I'll probably die. 😅
They have them on aircraft too
Sure about that? Aircraft are mostly non magnetic alloys and those steel balls weigh more than even a vacuum tube electronic compass.
@@dbmail545 A "whiskey" compass in a small aircraft has small, internal, adjustable magnets. There is a procedure termed "swinging the compass" where the aircraft is rotated about a "compass rose" and the magnets are adjusted to get the truest overall reading from the compass over all headings. A small card is then attached indicating the error for different headings.
Kevin's balls in every ship
Ships with a good compass can ferry-us to foreign lands.
I knew the us navy had balls😂😂😮😅😢😂😂
Went to school with a guy called Kelvin. I'm sure he'd know.
californium is a great nonferrious metal
Now explain Plimsoll Mark!
The origin of the Plimsoll mark is quite easy to explain. Lord Plimsoll is probably the person that singlehanded have done most for safety at sea. He noted that a number of ships sunk because they were overloaded and pressed forward a law in the English parliament that required all cargo ships to have a mark on the ship side to indicate the maximum weight they were allowed to load. Ironically is that the same ships that Plimsoll was after is the ones that is referred to as Plimsollers. In other words the worts wrecks.
In the years after Plimsoll the maximum allowable weight has been modified a little. You have now Summer-draft,Winter-draft,Freshwater,winter Atlantic and tropical draft. There are guidelines to tell you where and when these requirements apply and if you break them you are in for a heavy fine.
Well done. What is the purpose of the compass being in water?
The liquid in the compass is either alcohol or oil and is there to dampen the movement of the compass card.
So... How do you know how to set the distance at which the Magnetic Cast Iron Balls... That would even change with the Cargo you are carrying and what Ammunition (if they were Cannon Balls) you had aboard and how much of it.... I'm probably over thinking things....
Good idea for video and good commentary. However the clips and your pronunciation of non-ferrous make it seem much less serious. I strongly suggest you reproduce this clip and run it by a few people. This could be a really good video vs. one that I stopped part way through
@@pabloverdi7543: Trying out different formats to see what works and what doesn't. Thank you for the honest and POLITE feedback. 🙂 Greatly helps.
I’m only here for the comments.
SHIP, SHIP, HURRAY!!!!!!!!!!!!!!!!!!!!!!!!!!!
But how do magnets work?
Really well, actually.
Icp
@@eherrmann01: 😄😂🤣
@@USSSlater:
Too many memes
I can't watch the video if you can't pronounce words right
Fake
Lord Kelvin.....William Thomson, 1st Baron Kelvin, OM, GCVO, PC, FRS, FRSE...
en.wikipedia.org/wiki/Lord_Kelvin
Why didn't they just use GPS?