Get to know the device of the nautical compass according to the book by V.A. Dygalo "Where and what went in the Navy." Point out the fundamental difference in the design of a nautical compass and compasses land... How (along which line) was the compass installed on ships?
Answer
In a conventional compass, a magnetic needle rotates on a needle above a circular scale. In a nautical compass, the scale itself (card) rotates on the needle.
Card - a movable disk (or ring) made of non-magnetic material in a magnetic compass or of material in gyrocompass repeaters with graduations of the degree or bearing system evenly applied around the circumference.
The main difference between the two compasses is that the nautical compass has several magnets attached to the bottom of the card, the card rotates with them, with the north mark coinciding with the magnetic north pole. This is done for the convenience of taking readings; in the sea, the rose rotates more slowly than the arrow. In order to slow down the rotation even further, the compass housing is filled with a liquid, usually an antifreeze mixture of alcohols.
There is a mark on the body of the compass indicating the diametrical (longitudinal) line of the vessel; the direction on the compass rose, which coincides with this mark, indicates the compass direction in which the ship is moving. To steer with the compass, you need to turn the boat until the desired direction on the compass rose coincides with the course relative to the center line.
The technical means used to determine the main directions at sea also include magnetic compasses. Magnetic compasses use the property of a magnetized needle to be located along the magnetic field lines of the Earth's magnetic field in the north-south direction. On a ship, in addition to the Earth's magnetic field, the magnetic needle is affected by the magnetic fields created by the ship's iron and electrical installations. Therefore, the magnetic needle of the compass installed on the ship will be located in the so-called compass meridian.
Simplicity of the device, autonomy, constant readiness for action and small size are the advantages of a magnetic compass over a gyroscopic one.
But the readings of the magnetic compass must be corrected with an amendment, the magnitude and sign of which change depending on the course of the vessel, its location on the earth's surface and other reasons. At high latitudes, the accuracy of the readings of the magnetic compass decreases, and in the region of the magnetic and geographic poles of the Earth, it ceases to work altogether.
All ships in the marine fleet are equipped with marine magnetic 127 mm (5 ") compasses (Fig. 131).
The main parts of the compass are: bowler hat 1 with a rose, binnacle 2, direction finder 3 and deviation device 4.
Bowler hat (Fig. 132) is a cylindrical brass tank, divided into two chambers that communicate with each other. In the upper chamber 1 is placed a compass card, the lower 2 serves to compensate for changes in the volume of compass fluid with fluctuations in ambient temperature.
A solution of ethyl alcohol (43% by volume) in distilled water, which freezes at a temperature of -26 ° C, is used as a compass fluid. To reduce the vibrations of the pot during rocking, a brass cup with a lead weight is attached to the bottom of its body 3.
The pot is equipped with a cardan ring, which allows keeping the azimuth ring of the pot in a horizontal position.
Card (Fig. 133) - the main part of the compass, consists of a system of magnetic arrows 1, a float 2, an agate firebox 3, a screw for fastening a firebox 4, six brackets 6 supporting a mica disk 5, on which a paper disk is glued, divided into points and degrees ...
Figure: 131.
Figure: 132.
Direction finder - a special device for determining directions to visible objects and celestial bodies. It consists of a base, object and eye targets and a deflector cup.
Binnacle made from silumin. The main parts of the binnacle are: body, upper and lower bases, shock-absorbing suspension, deviation device and protective cap.
Figure: 133.
Deviation device is placed inside the binnacle and is a brass tube with two movable carriages for installing annihilation magnets. A set of magnets for the elimination of semicircular deviation is attached in a special wooden case.
All 127mm compasses produced have bottom illumination of the rose. The lighting system includes: an umformer, a power supply unit and a lamp holder (in case of power supply from the ship's DC network).
The lighting system can operate on a ship's alternating current, but in this case, instead of an umformer, a transformer is included in the power circuit, reducing the current voltage to 6.12 or 24 V.
The next day, the frigate "Ringing" again carelessly ran under sail in the open ocean, and on its deck the classes continued.
- First of all, I want to tell you that the sailors say not "to about mpas "and" comp and s ", - said Yakov Platonovich, because the turn has come to get acquainted with this nautical instrument.
Proof of this is another sea song of the writer Alexander Green, I really like it.
The Southern Cross shines there in the distance,
The computer will wake up with the first wind andfrom.
God, keeping the ships,
May he have mercy on us ...
For God to really keep the ship on a long voyage, sailors themselves must skillfully manage their ship. And the compass in this matter is their main and reliable assistant.
Of course, the nautical compass differs from the land compass not only by the accent in the name ...
- Also in size, right? - Vasya asked.
- The magnitude is by itself. - But there is also a fundamental difference in design.
In an ordinary tourist or school compass, a magnetic needle runs on a needle. It moves with its end over a circular scale with divisions and letters.
And in the nautical compass, the scale itself settled on the needle.
It is called KART Have SHKA. It looks like the word "card". Such a round card with divisions of degrees, made of waterproof cardboard or plastic.
- Does the compass flood with waves? - Anton was surprised.
- Of course not. It is closed at the top with waterproof glass with a rubber gasket. The waterproof card is needed for something else ... Let's take a closer look at the structure of the nautical compass, then you will understand everything.
Yakov Platonovich opened the cupboard and took out a small black vessel. Instead of handles, the vessel had a ring around the upper part.
- Bowler hat! - Anton was surprised. - Smoked at the stake ...
- You're right. This case of the ship's magnetic compass is called the bowler hat. The bottom is heavy. Therefore, when the bowler hat is suspended in this ring (it is called a standard ring), the compass maintains an even horizontal position for any roll.
But, of course, the pot is not smoked, but painted black. It's actually brass. You can't make it iron, magnetic arrows would immediately go astray.
At the bottom of the pot there is a shp and lk with a point made of very strong metal. The card sits on the hairpin.
The compass card is arranged like this. In its center there is a hollow, thin brass float fortified. It looks like a flattened ball. At the bottom of it is a small inverted cup made of hard stone (usually agate). It is called top (similar to the word "top", isn't it?). A firing float and put on the tip of the hairpin. It sits on a hairpin very easily. A special liquid is poured into the pot, and in the liquid the float makes the card almost weightless ...
- So that's why the card is waterproof! Because in liquid! - Anton guessed.
“A weightless card, of course, turns more easily on a needle,” Slava remarked.
- And besides, - said Yakov Platonovich, - the liquid serves as a brake for the card: it does not allow it to spin without a goal and dangle too much ...
But, to be precise, the rose inside the compass does not rotate. Nearly. At least she always tries to stay still. And the compass bowler revolves around her. Together with the ship. Yes, yes! .. The fact is that arrows are attached to the float at the bottom - magnetized steel strips in lead cases. There are several of them. Some compasses have two, but this one, Russian model, has six ...
- For balance? - asked Slava.
- Not only. Several arrows are more accurate than one in the north-south direction.
Keeping this position, the arrows also hold the float with the card. Therefore, the card with its northern mark (there is the number 0 and the letter N) always looks north, no matter which direction the ship is going.
See what happens? The ship changes course, its hull turns, with it the compass bowler with a black wire stretched in it - the course thread. And thanks to the arrows, the card is always in the same position. The heading thread runs in front of its edge and shows the course. Because the card contains the designations of the cardinal points and all 360 degrees. Zero degrees is exactly north.
Compass device
When it is necessary to determine where the ship is going, they look at the compass and report what the guidance thread shows. For example: "Heading forty-five degrees" or "heading northeast" ...
- And what is "nord-ost"? - asked Ksenya.
- North-east. But more on that later. Let's finish the question about the compass device.
Look, a bubble is floating in the liquid under the glass. The fact is that this compass is old, they gave it to me when it had already served its term. In general, there should be no bubbles in the liquid. For this, at the bottom of the compass there is a special elastic plate - a membrane, and under it is a small chamber with air. The membrane, due to the elasticity of the air, supports the liquid and squeezes out the bubbles.
Compasses come in a variety of sizes. They differ in diameter (i.e., transverse width) of the rose. This one is big, 127mm. It is put on large ships. There are smaller ones - 100 mm. And there are boat compasses, they have a 75-mm rose.
- Just like the caliber of the shells, - Vasya remarked.
- Yes. But the compass is a peaceful thing, it serves for the safety of navigation. Without him, not a single captain will go to sea.
- And what is the liquid in the pot? - asked the inquisitive Slava. - She will not freeze if the ship floats among the ice, at the pole?
- She does not freeze even in a hard frost. Sometimes it is a mixture of glycerin and alcohol. And in the compasses of this system there is just a solution of ethyl alcohol, in other words, wine ...
Vasya chuckled. Yakov Platonovich also grinned:
- Yes, there are many anecdotes on this score: about navigators who poured the contents of the cauldron into themselves and confused north and south ... Remember, I told you about the Neptune festival, which was organized by the trainees on the barkentine? There was also an episode in their performance: during the exam, Neptune asks the question:
Well, who will tell me now
what is l and e l - with p and r t?
You will, of course, remember that this is a part of the mast for the additional sail of the boat. But in the play the "stupid" cadets do not know this. And one bravely replies:
But this, of course, is for fun. I have met all kinds of sailors in my life, including those who loved to sip too much. But I have never seen such fools who would try to use the contents of the compass pot for this ... Well, they laughed and drove on.
A large ship usually has several compasses. The main one is called the main one. It is installed on the upper bridge, it is used to set the course of the ship and check the readings of other compasses. The tracked compass is in front of the steering wheel - the helmsman leads the ship along it. In different places of the ship there may be several more compasses - spare and for additional control.
In one maritime museum I saw an old compass especially for the captain. He is inverted. Instead of the bottom in the pot there is glass, and through it you can see the card. Such a compass was screwed to the ceiling of the cabin. The captain could follow the course without leaving his bunk. I slept, opened my eyes, made sure that everything was in order and - you can look at your dreams further while experienced assistants are on duty ...
But usually compasses are not mounted on the ceiling, but on special bedside tables - wood or non-magnetic alloy.
This bedside table is called NAKTOUZ. Translated from Dutch - "night house". Because on such a bedside table, the compass is always under a special cover or cap - like in a house under the roof. And at night a light is on there. In calm weather, it looks cozy - like a light in a forest hut. I remember reading these verses in one book:
We're floating in darkness without lights
Leaving all the chases.
And only stealthily at the stern
Burns like a candle on the window
Binnacle fire ...
Binnacles come in many forms. On our "Meridian" there was a wooden steering wheel, and the cap above the compass looked like a copper diver's helmet with cylindrical attachments on the sides. These were spare oil lamps for illuminating the card - in case the engine deteriorates, there is no electricity and the light in the bottom of the compass pot goes out ...
And inside any binnacle there is a special device with magnets to eliminate compass errors.
- Are there mistakes in the compass? - Vasya was surprised.
- Of course. Every ship, even a wooden one, has a lot of all kinds of iron. It greatly affects the magnetic arrows under the card ... Those who read the book "Fifteen Years Captain" remember how the villain Negoro thrust an iron bar under the compass. The card went off, and the brigantine "Pilgrim" sailed past America ... Well, now there can be no such huge mistakes, but there are as many minor annoying errors as you like.
By the way, the deviation of the compass card under the influence of the ship's iron is called deviation. To reduce it, there are regulator magnets in the binnacle.
But it is rarely possible to completely remove the deviation. Therefore, the navigator must always take it into account when plotting a course - add or subtract degrees of correction.
And it is also necessary to take into account the mag netic slope.
The fact is that the geographic poles of the Earth - North and South - do not coincide with the magnetic poles that control the compass arrows. For example, the North Magnetic Pole is located in Greenland. Magnetic poles deflect arrows away from true north and south. Far from the poles this is not very noticeable, but in polar waters the difference is great. This difference between the directions to the magnetic and geographic poles is called the magnetic inclination.It is measured in degrees and can be east or west - depending on where the magnetic force is pulling card from the geographic pole. Rather, from the meridian that passes through this pole.
I must say that meridians can also be drawn through the magnetic poles. They are called so - magical. And the meridians passing through the geographic poles are called - stinnye.
Magnetic declination is the angle between true and magnetic meridians.
To facilitate the work of navigators, compass cards are printed on nautical charts and they indicate what declination is in this area of \u200b\u200bthe sea.
There is always a lot of fuss with declination and deviation, and to avoid it, engineers invented compasses without magnetic needles, - said Yakov Platonovich.
- How do these compasses work? - Slava was amazed.
- I'll explain ... Ksenya, yesterday I repaired your bicycle and took off the front wheel. Please bring it from the hallway.
Of course, Vasya was ahead of Ksenia and brought the wheel himself.
- Slava, hold him by the axis, from both sides, - ordered Yakov Platonovich. - And try to promote the rest ... Careful ... Careful, but harder ... That's it. And now, Slava, try to quickly turn the axis, change the inclination of the wheel ...
Slava tried it. Did not work out! The wheel swiftly rustling in the air did not obey the boy! It wished to remain in the same position with its axis.
- You see! - Yakov Platonovich said with delight. - This is called ef f e k t g and ros cop a.
G and rosko p is a rapidly rotating disk or top. He always tries to maintain the position of his axis in space.
- Like a child's whirligig! - Anton exclaimed. - She also does not fall when spinning!
- Correctly! Yula is also a gyroscope ... Now imagine that one end of the axis is directed to the north, and the other, thus, looks to the south. We spin the disk ... The axis is instead of an arrow. And no magnetization is needed.
- How simple! - Ksenia exclaimed.
- No, friends. I try to explain this in a simpler way. In fact, the axis will not look at the poles for a long time: after all, the Earth changes its position in space - unlike a gyroscope. Therefore, the compass, which is called g and ros kopichesk and m, is a very complex device. It contains a whole system of gyroscopic tops, they are hidden inside a hollow ball - a gyrosphere. The gyrosphere has an amazing property. When gyroscopes are launched in it with the help of electricity, under their influence, as well as under the influence of the rotation of the Earth, it rises to the desired position - with the northern mark of its ring exactly to the North Geographic Pole.
True, the gyrosphere does this not immediately, gradually. And you should not rush it. Therefore, the gyrocompass is turned on before sailing.
- I would like to see, - said Slava, who finally lowered the wheel (hands are tired).
- Unfortunately, I don't have a gyrocompass. This is a very expensive thing and, moreover, cumbersome. The size of a keg ... The gyrocompass is installed in the depth of the ship's hull so that there are fewer mechanical influences.
- And there, in the depths, does the navigator climb every time to check the course? - Slava was upset.
- Not at all! From this compass, which is called a m and a, electric cables stretch to special devices - repetitions, in translation into Russian "repeater" means "repeating".
Repeaters are like magnetic compasses. Only their cards are controlled not by magnetic arrows, but by electrical signals coming from the gyrocompass. And on all repeaters - the same readings.
Convenience is that there can be as many repeaters as you like and you can place them throughout the vessel.
- But, then, there is some inconvenience? - Slava asked knowingly.
- Unfortunately, there is. The gyrocompass is a capricious device ... We had a navigator on the barkentin who liked to tell a story-anecdote, with a kind of Odessa humor.
"There are two motor ships sailing on the Black Sea. One watchman shouts from board to the other:
- Hey, brothers-sailors, where are you going ?!
“What’s that, you don’t see it yourself, do you? It is clear that to Odessa-mother!
- No, listen, this man is talking to me! We are going to Odessa, and you are exactly the opposite!
- Sho you tell me, young man! Do we have Odessa? In the north! And de we have the sun? Back at pivden, because it's neatly twelve o'clock now. It shines for us in the stern. So we are heading north!
- What do you want to say? Shaw the sun is in the south every noon?
- Ha! You don't know such simple astronomy? Yak, then, do you drive your trough, excuse me, on the sea?
- Yes, we have a gyrocompass!
- And with us! It is he who shows the course to the north!
- So we go to the north! .. Lads, call the captain to the bridge, with geography full of hominy! .. "
It turned out that on one ship the gyrosphere in the uterus took on its own whim and turned one hundred and eighty degrees. That is, backwards. Sometimes they can do such tricks. Therefore, you need an eye and an eye ...
When they had finished laughing, Yakov Platonovich continued:
- Well, besides, the gyrocompass depends on the power supply. What if suddenly there is an accident with a car and there is no electricity? Once such a story happened to us near the Azores - the engine went out. Okay, let's go sailing. Where to go if the gyro is turned off? This is where the magnetic compass helped us out. Old, well-deserved, but reliable - it never turns off.
On the most modern ships, magnetic compasses are mandatory. You never know what happens at sea. The vessel should not lose the ability to sail if the energy has disappeared. Especially the sailboat. Therefore, the vessel should always have tools that are not dependent on electricity.
“The law of the gramophone,” said Ksenya.
- What is the law? - Vasya was surprised.
- It was my grandfather who invented it. When we celebrated the New Year, the lights suddenly went out, an accident in the transformer box. There are screams and complaints throughout the house: the chandeliers are not lit, the garlands on the Christmas trees are out, the TVs are not working. And grandfather lit candles and pulled out an old gramophone. Well, you know, such a suitcase with a spring inside and a handle for the winding, and put the record:
Why are you, friends, depressed?
Or have you forgotten the sea songs?
And we celebrated so well. It was even a little annoying when the electricity turned on.
- Since there is no gyrocompass, maybe let's see a gramophone? - suggested the simple-minded first grader Anton. - And let's listen to the records?
Yakov Platonovich said that it is possible.
And soon the shabby gramophone, which the boatswain Peryshkin had kept since childhood, played a disc with a song from the same old film "Children of Captain Grant":
There lived a brave captain
He traveled to many countries ...
The cats sat at the gramophone and listened with their heads bowed. The syntax wanted to touch the shiny head of the membrane, but Yakov Platonovich said: "I will ..." And the splayed Sinkin's paw froze in the air.
- And the disk at the gramophone is also almost a gyroscope, - Vasya remarked, - That's how it turns!
The record is over. And, before turning it over, Yakov Platonovich said:
“We're not done with the compass yet. Tomorrow I will tell you about the divisions on his card.
