Marine magnetic compass. Navigation devices and instruments. Magnetic compass device. Magnetic compasses UKP-M and KMO-T

BINNACLE

BINNACLE

(Binnacle) - a cupboard made of teak, oak or mahogany on which the compass is mounted on a ship. N.'s form varies; so, for example, at 8-inch. compass N. has the form of an octagonal truncated pyramid, 5-inch. - a straight prism with a square cross-section; in the compass of V. Thomson, N. has the shape of a cylinder. The N. is made high for installing the main ship's compasses and low for installing the directional compass. At the top N. is placed spring suspension, on which it is installed compass bowler the axles of his cardan rings. Inside N. is installed deviation device, serving to destroy semicircular and roll deviation. To eliminate the quarter deviation, N. is supplied with soft iron of various shapes and in the proper quantity. Soft iron is placed mainly outside and partly inside the N. In addition to the parts already listed, the N. also has devices for illuminating the compass at night with electric light and for bell signaling between different compasses. On ships, the N. is usually installed on wooden pillows made of strong wood (oak, teak). The N. is attached to the pillow with bolts, and for greater stability when rolling, it is strengthened on the sides with two copper backstays.

Samoilov K. I. Marine Dictionary. - M.-L.: State Naval Publishing House of the NKVMF of the USSR, 1941

Binnacle

a stand in the form of a four or hexagonal cabinet on which the compass bowl is mounted and in which there are magnets on special mounts that serve to eliminate compass deviation. The binnacle is covered with a cap on top, protecting it and the compass from rain and snow.

EdwART. Explanatory Naval Dictionary, 2010

Binnacle

a box or scale on which a compass is mounted.

EdwART. Marine Dictionary, 2010

See what "Naktouz" is in other dictionaries:

- (Gol. nagthuis, from German. Nacht night, and Haus house). On a ship there is a place under the glass where the compass is placed. Dictionary of foreign words included in the Russian language. Chudinov A.N., 1910. BINCTUAL goal. nagthuis, from German. Nacht, night, and Haus, house. Place on… Dictionary of foreign words of the Russian language

- (from Dutch nachthuis, “night house”) box, in ... Wikipedia

Locker Dictionary of Russian synonyms. binnacle noun, number of synonyms: 1 locker (12) ASIS Dictionary of Synonyms. V.N. Trishin. 2013… Dictionary of synonyms

binnacle, binnacle, man. (Dutch nagthuis) (mor.). A box with a glass lid for a compass on the deck of a ship. Dictionary Ushakova. D.N. Ushakov. 1935 1940 ... Ushakov's Explanatory Dictionary

Male, Marine a type of cabinet, a box on a stand, in which there is a straight compass, i.e. according to which the helmsman rules. Binnacle, related to binnacle Dahl's Explanatory Dictionary. V.I. Dahl. 1863 1866 … Dahl's Explanatory Dictionary

binnacle- A stand on which the compass bowl is mounted and in which there may be devices for placing and installing devices intended for regulating and illuminating the compass. [GOST R 52682 2006] Topics of navigation aids, surveillance... Technical Translator's Guide

Marine radio equipment – ​​equipment intended for security human life at sea, ensuring the safety of navigation, managing the operation of the fleet and transmitting public and private correspondence. To effectively use radio equipment on ships, it is necessary to know its construction principles, technical specifications and operating features. Depending on the navigation area, different requirements are put forward for marine radio equipment.

A1 – in the coverage area of ​​coastal VHF radiotelephone stations using DSC.
A2 – in the coverage area of ​​MF radiotelephone stations using DSC, excluding area A1.
A3 – within the range of INMARSAT satellites, excluding areas A1 and A2.
A4 – outside the areas A1, A2, A3.
Thus, the radio equipment on the ship consists of three complexes: VHF equipment, MF/HF equipment and a ship earth station (SES) of the INMARSAT system. Regardless of the navigation areas, each vessel must be equipped with: a VHF radio installation, a radar beacon (radar transponder), a NAVTEX receiver, an EPIRB (emergency radio buoy), and portable emergency VHF radios.

The radio equipment on the ship must meet the GMDSS requirements specified in the rules of the RMRS (Russian Maritime Register of Shipping) and RRR (Russian River Register). Each ship must carry a reserve power source to enable radio equipment to provide distress communications in the event of failure or damage to the main and emergency power sources. When moving from one power source to another, light and sound alarms should sound. For operation and repair of equipment is provided maintenance, which performs the following procedures: delivery to the installation site, storage (if necessary) and installation. All these steps must be carried out in accordance with the instructions in the technical documentation.

The quality of radio equipment is a set of indicators that determine its compliance with modern requirements of science and technology. Quality indicators of a device include reliability, performance characteristics, efficiency, safety, design, etc. Many indicators have a numerical value and, in essence, determine the effectiveness of the use of any equipment on the ship.

On ships with a displacement of over 500 r.t. there must be at least three VHF portable stations and two radar transponders. On ships with a displacement from 300 to 500 r.t. - two stations and 1 radar. It is also recommended to equip ships with equipment for receiving facsimiles.

In the company's product catalog you can find various models and brands of global radio equipment manufacturers and make the necessary order.

Contents of the article

COMPASS, a device for determining horizontal directions on the ground. Used to determine the direction in which a ship, aircraft, or land is moving vehicle; the direction in which the pedestrian is walking; directions to some object or landmark. Compasses are divided into two main classes: magnetic compasses of the pointer type, which are used by topographers and tourists, and non-magnetic ones, such as the gyrocompass and radio compass.

Compass card.

To determine directions, the compass has a card (Fig. 1) - a circular scale with 360 divisions (corresponding to one angular degree each), marked so that the countdown is clockwise from zero. The direction to the north (north, N, or S) usually corresponds to 0°, to the east (east, O, E, or B) - 90°, to the south (south, S, or S) - 180°, to the west (west , W, or Z) – 270°. These are the main compass points (cardinal points). Between them there are “quarter” directions: north-east, or NE (45°), south-east, or SE (135°), south-west, or SE (225°) and north-west , or NW (315°). Between the main and quarter directions there are 16 “main” directions, such as north-north-east and north-north-west (once there were 16 more points, such as “north-shadow-west”, called simply points).

MAGNETIC COMPASS

Operating principle.

In a direction-indicating device, there must be some reference direction from which all others are measured. In a magnetic compass, this direction is the line connecting North and South pole Earth. The magnetic rod will set itself in this direction if it is hung so that it can rotate freely in the horizontal plane. The fact is that in the Earth’s magnetic field, a rotating pair of forces acts on the magnetic rod, setting it in the direction of the magnetic field. In a magnetic compass, the role of such a rod is played by a magnetized needle, which, when measured, is itself set parallel to the Earth’s magnetic field.

Pointer compass.

This is the most common type of magnetic compass. It is often used in a pocket version. A pointer compass (Fig. 2) has a thin magnetic needle mounted freely at its midpoint on a vertical axis, which allows it to rotate in a horizontal plane. The northern end of the arrow is marked, and the card is fixed coaxially with it. When measuring, the compass must be held in your hand or mounted on a tripod so that the plane of rotation of the arrow is strictly horizontal. Then the north end of the arrow will point to the north magnetic pole of the Earth. A compass adapted for topographers is a direction-finding instrument, i.e. device for measuring azimuth. It is usually equipped with a telescope, which is rotated until it is aligned with the desired object, in order to then read the azimuth of the object using the card.

Liquid compass.

The liquid compass, or floating card compass, is the most accurate and stable of all magnetic compasses. It is often used on sea vessels and is therefore called shipboard. The designs of such a compass are varied; in a typical version, it is a “pot” filled with liquid (Fig. 3), in which an aluminum cartridge is fixed on a vertical axis. On opposite sides of the axis, a pair or two pairs of magnets are attached to the card from below. In the center of the pot there is a hollow hemispherical protrusion - a float, which relieves pressure on the axle support (when the pot is filled with compass liquid). The axis of the card, passed through the center of the float, rests on a stone thrust pad, usually made of synthetic sapphire. The thrust bearing is fixed on a fixed disk with a “course line”. There are two holes at the bottom of the pot through which liquid can flow into the expansion chamber, compensating for changes in pressure and temperature.

The card floats on the surface of the compass liquid. The liquid, in addition, calms the vibrations of the card caused by pitching. Water is not suitable for a ship's compass because it freezes. A mixture of 45% ethyl alcohol with 55% distilled water, a mixture of glycerin with distilled water, or high-purity petroleum distillate is used.

The compass bowl is cast from bronze and equipped with a glass cap with a seal that eliminates the possibility of leakage. An azimuth, or direction-finding, ring is fixed in the upper part of the pot. It allows you to determine the direction to various objects relative to the ship's course. The compass bowl is fixed in its suspension on the inner ring of the universal (universal) joint, in which it can rotate freely, maintaining a horizontal position, in rolling conditions.

The compass bowl is fixed so that its special arrow or mark, called the course, or a black line, called the course line, points to the bow of the vessel. When the ship's course changes, the compass card is held in place by magnets, which invariably maintain its north-south direction. By shifting the heading mark or line relative to the card, you can control course changes.

COMPASS CORRECTION

A compass correction is the deviation of its readings from the true north (north). Its causes are magnetic needle deviation and magnetic declination.

Deviation.

The compass points to the so-called compass, and not to the magnetic north (north magnetic pole), and the corresponding angular difference in directions is called deviation. It is caused by the presence of local magnetic fields superimposed on the Earth's magnetic field. A local magnetic field can be created by the hull of a ship, cargo, large masses of iron ore located near the compass, and other objects. The correct direction is obtained by taking into account the deviation correction in the compass readings.

Ship magnetism.

Local magnetic fields created by the ship's hull and covered by the concept of ship magnetism are divided into variable and constant. Alternating ship magnetism is induced in the steel hull of the ship by the Earth's magnetic field. The intensity of alternating ship magnetism varies depending on the ship's course and geographic latitude. Permanent ship magnetism is induced during the construction of a ship when, under the influence of vibration caused, for example, by riveting operations, the steel plating becomes a permanent magnet. The intensity and polarity (direction) of a ship's permanent magnetism depend on the location (latitude) and orientation of the ship's hull during its assembly. Permanent magnetism is partially lost after the ship is launched and after it has been in rough seas. In addition, it changes somewhat during the “aging” of the hull, but its changes significantly decrease after the vessel has been in use for a year.

Ship magnetism can be decomposed into three mutually perpendicular components: longitudinal (relative to the ship), transverse horizontal and transverse vertical. Deviations of the magnetic needle caused by the ship's magnetism are corrected by placing permanent magnets parallel to these components near the compass.

Binnacle.

A ship's compass is usually mounted in a universal joint on a special stand called a binnacle (Fig. 4). The binnacle is rigidly and securely attached to the deck of the ship, usually on the centerline of the ship. Magnets are also installed on the binnacle to compensate for the influence of ship magnetism, and a protective cap for the compass with an internal card illuminator is attached. Previously, the binnacle was made in the form of a carved figure made of wood, but on modern ships it is simply a cylindrical stand.

Magnetic declination.

Magnetic declination is the angular difference between the magnetic and true north, due to the fact that the Earth’s magnetic north pole is shifted by 2100 km relative to the true, geographic one.

Declination map.

Magnetic declination varies over time and from point to point on the earth's surface. As a result of measurements of the Earth's magnetic field, declination maps were obtained, which give the magnitude of the magnetic declination and the rate of its change in different areas. The contours of zero magnetic declination on such maps, emanating from the north magnetic pole, are called agonic lines or agons, and the contours of equal magnetic declination are called isogonic or isogonic.

Accounting for compass corrections.

Currently, a number of different methods are used to take into account compass corrections. All of them are equally good, and therefore it is enough to cite as an example only one, adopted by the US Navy. Deviations and magnetic declinations to the east are considered positive, and to the west - negative. Calculations are made using the following formulas:

Magn. eg = Comp. eg + Deviation,

Comp. eg = Magn. eg + Declension.

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 lines of force of the Earth's magnetic field in the north-south direction. On a ship, the magnetic needle, in addition to the Earth's magnetic field, is affected by magnetic fields created by the ship's iron and electrical installations. Therefore, the magnetic needle of a compass installed on a 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 by a correction, the magnitude and sign of which vary depending on the course of the ship, its location on the earth’s surface and other reasons. At high latitudes, the accuracy of the magnetic compass readings decreases, and in the area of ​​the Earth’s magnetic and geographic poles it ceases to function at all.

All naval vessels are equipped with marine magnetic 127 mm (5 inch) compasses (Fig. 131).

The main parts of the compass are: bowl 1 with a card, binnacle 2, direction finder 3 and deviation device 4.

Bowler(Fig. 132) is a brass cylindrical tank divided into two chambers that communicate with each other. The upper chamber 1 houses the compass card, the lower chamber 2 serves to compensate for changes in the volume of the compass fluid when the ambient temperature fluctuates.

A solution of ethyl alcohol (43% by volume) in distilled water, which freezes at a temperature of -26°C, is used as a compass liquid. To reduce the vibrations of the pot during pitching, a brass cup with a lead weight 3 is attached to the lower part of its body.

The bowler is equipped with a cardan ring, which allows you to keep the azimuth ring of the bowler in a horizontal position.

Cartushka(Fig. 133) - the main part of the compass, consists of a system of magnetic needles 1, a float 2, an agate firebox 3, a screw for fastening the firebox 4, six brackets 6 supporting a mica disk 5, onto which a paper disk is glued, divided into points and degrees .

Rice. 131.

Rice. 132.

Binnacle made from silumin. The main parts of the binnacle are: body, upper and lower bases, shock-absorbing suspension, deviation device and protective cap.

Rice. 133.

All manufactured 127 mm compasses have a bottom illuminated card. The lighting system includes: a umformer, a power supply and a socket with a light bulb (if powered from the ship's DC network).

The lighting system can operate on ship's alternating current, but in this case, instead of an umformer, a transformer is included in the power circuit, reducing the voltage to 6.12 or 24 V.

A compass is a navigation device designed to determine the course of a ship and directions to various coastal or floating objects that are in the field of view of the navigator. The compass is also used to determine the direction of the wind and the drift of the ship. Based on the readings of the magnetic compass, the ship is controlled, and with its help, bearings are determined to coastal objects. Typically, a magnetic compass is installed in a high, open place in the centerline of the ship.

The magnetic compass uses the property of a magnetic needle to set its ends in the direction of the magnetic field acting on it. In addition to the earth's magnetic field, the ship's compass needle is also affected by the magnetic field created on the ship by the iron hull and iron pieces of equipment. Under the influence of these two forces, the magnetic needle is established in the plane of the compass meridian. A magnetic compass is also subject to the influence of other external forces that arise when the ship rolls and turns, which remove the needle from a stable position. The compass needle is also affected by the vibration of the housing from engine operation.

In marine magnetic compasses, the role of the needle is played by a system of four, six or more thin magnets placed in a pot of liquid, which quickly damps the vibrations of the magnetic system.

For compasses used on land, including tourist ones, a scale with degree division is printed on the compass body. Such a compass, installed on a ship, will rotate with the ship and the reference scale. - WHY ALL THIS?????????????????????????

An air float keeps the magnetic system afloat, which ensures minimal friction at the suspension point. A marine magnetic compass is equipped with a special device - a deviation device, which reduces the impact of the magnetic field of the iron hull of the ship on the magnetic system of the compass. With the help of a gimbal suspension, the horizontal position of the pot is ensured during pitching, roll and trim. NO BASIC FORMULA

3.2. Methods for determining compass correction. MEANING GYROCOMPASS

A compass correction is the value of a parameter (course or bearing) that compensates for the systematic error in its measurement.

To determine the correction of any compass, it is necessary to compare the true and compass directions to the same landmark, i.e.:

∆MK = IP – CP.

Determination of compass correction along the target. The target IP is removed from the map. The control point is taken at the moment of crossing the alignment line. Determination of compass correction along natural coastal alignments (for example, sections of two capes). At the moment of crossing the line of natural alignments, the compass bearing is taken and compared with the direction of the line taken from the map passing through the sections of the two capes.

Determining the compass correction based on the bearing of a distant landmark. This method is used when the vessel is anchored, when the landmark and anchorage location is precisely known.

Determining the compass correction by comparison with another compass whose correction is known. The method is used to determine the correction of the main and traveling magnetic compasses by comparing the readings with a gyrocompass, the correction of which is known. On command, two observers simultaneously note the heading on both compasses. Define:

∆MK = (GKK + ∆GK) – KK.

Determination of the compass correction when determining the ship's position using three bearings. When determining the position of a ship using three bearings, a so-called triangle of errors may appear, i.e., the laid position lines do not intersect at one point. When there is confidence in the correct identification of landmarks and in the absence of gross errors in bearings, and the triangle turns out to be large, this indicates an error in the adopted compass correction. To eliminate such an error, and at the same time determine the current compass correction, proceed

as follows:

– all bearings are changed by 3-5 0 in one direction or another, and after laying a new triangle of errors is obtained;

– lines are drawn through the similar vertices of the old and new error triangles, and the point M of their intersection is taken as an observed place on the vessel, free from the influence of a systematic error in the compass correction ∆K;

– point M is connected to landmarks on the map and the resulting true bearings are measured with a protractor. By comparing them with the compass bearings of the same landmarks, three values ​​of the compass correction are found ∆K = IP - KP. The arithmetic mean of the results obtained is taken as the actual correction for a given course.

When determining the compass correction by an astronomical method, the bearing to the luminary, measured using a direction finder, is used as the compass direction, and the calculable azimuth of the given luminary, calculated at the time of measurement in a tabular or machine way, is used as the true direction.

The following conditions must be met:

1. To clarify ∆K, use luminaries located at a low altitude (h< 30°) и вблизи диаметральной плоскости судна (КУ< 30°);

2. Measurements should be made in series of 3-5 bearings with re-fixation of the direction finder;

3. The bearing is measured with an accuracy of 0.1°, the measurement moments are recorded with an accuracy of no worse than 2-3 s;

4. The countable azimuth must be converted into a circular count, i.e. IP = A k.

There are several ways to determine AK by luminaries:

1. Determination of ∆K from a star located at an arbitrary azimuth;

2. Determination of ∆K from the Sun at the moment of its true rising and setting;

3. Determination of ∆K from observations of the North Star.

The first method is the main and most common, the other two are its special cases. It is performed in the following sequence:

Example: August 24, 2006, Mediterranean Sea. V T s = 20:46′; N=1E; Measured a series of compass bearings: α Scorpio

– KP av = 219.5°; T gr.av. = 19:45′ 07″, ϕ с = 33°19.0′ N; λ c = 21°43.0′ E; KK = 196.0°, determine ∆K.

1. Calculate from MAE δ and t m of the star α Scorpius on T gr.av. =19: 45′ 07″

2. Calculate the true bearing of the star in one of the following ways: – using TVA tables:

Using a calculator using PT formulas: SHIPMENTS WILL NOT UNDERSTAND

Ctg A = cosϕ · tgδ · cosec tм - sinϕ · ctg tм

Сtg A = 0.8356∗ - 0.4975 ∗ 1.4525 – 0.5493 ​​1.0547 = -1.1825

A = arcctg – 1.1825 = 40.22°; A k = 220.2°

on a computer using the “Electronic Almanac” program А к = 220.2°

3. Calculate the compass correction:

∆K = IP – CP = 220.2° - 219.5° = + 0.7°. – the symbols in the formulas are NOT CLEAR

Determination of ∆K by the Sun at the time of its rising and setting:

If at the moment of sunrise or sunset (at the moment the horizon touches its lower edge) you measure its compass bearing, then you can quickly and fairly accurately determine the compass correction. Specifics this method is that at the moment of sunrise (sunset) the height of its center is equal to a very specific value (- 24.4′ cm. MT-2000), therefore the desired Azimuth is a function of two parameters - latitude and declination. Therefore, A c is easier to calculate and easier to tabulate. To calculate the azimuth of the Sun, table 3.37 MT-2000 is used. The input arguments in Table 3.37 are the countable latitude - ϕ с, taken from the pad at the time of measuring the compass bearing, and the declination of the Sun - δ о, which is selected from the MAE at the Greenwich moment of sunrise (sunset). The tabulated azimuth is given in semi-circular count; The first letter of the name is the same as the number latitude, and the second letter at sunrise is E, and at sunset it is W.

It should be remembered that the instantaneous compass correction obtained in this way is less accurate and reliable than that obtained by the main method, so it is often used only for control.

Example: April 12, 2006; Black Sea. ϕ с = 44°25.0′ N; λ c = 34°12.0′ E; CC = 92.0°; T s = 06:08′; N=3E; We measured the compass bearing of the Sun at the moment of its rise: KPo = 77.2°; determine ∆K.

1. Determine the Greenwich time of sunrise and at the obtained moment select the declination of the Sun from MAE:

T gr = T s ± N W/E = 06:08′ – 3 = 03: 08′

At T gr = 03:08′ 04/12/02 from MAE - δ o = 08°36.0′ N

2. Included in the table. 3.37 MT-2000 with ϕ с = 44°25.0′ N and δ о = 08°36.0′ N and obtain on April 12 А t = N 77.7° E, taking into account

interpolation by ϕ and δ o results in A k = IP = 77.5°.

3. Calculate ∆K = IP – CP = 77.5° - 77.2° = + 0.3°. THE SAME THING – IT’S UNCLEAR WHAT’S WHAT’S WHAT

3.3. Practical methods for determining the deviation of a magnetic compass.

Usually the residual deviation is determined after its destruction, but sometimes the determination of deviation can be performed as independent work. Such a need arises if a noticeable discrepancy between the observed deviation on individual courses and its tabulated values ​​is detected, as well as when transporting metal cargo, after sailing in ice, or when the ship’s latitude changes significantly.

Distinguish full definition deviations for compiling a deviation table and partial, on individual courses, in order to control the operation of the magnetic compass.

To compile a table, deviation is most often determined at eight main and quarter compass courses, then, based on the observed deviation values, deviation coefficients A, B, C, D and E are calculated. Next, using known coefficients, a deviation table is calculated for any number of courses using formula (1) . Depending on the value of the coefficients, the deviation table is calculated for 24 or 36 courses. If any coefficient exceeds 3°, the table is compiled in 10° intervals, and for smaller coefficients - in 15° intervals. The input argument to the table is the compass heading.

The deviation table is signed by the person who determined it. The calculated values ​​of deviation coefficients are also entered into the table.

Determination of deviation is carried out on the pole or at low speed of the vessel, and before proceeding to determine the deviation on a new course, it is necessary to wait 3 - 5 minutes necessary for the vessel to remagnetize. In each course, if possible, the deviation should be determined from 3 to 5 observations, and the result should be averaged. The accuracy of bearing or heading readings must be no less than 0.2°.

All main methods of determining deviation come down to comparing magnetic directions (bearings, headings) with directions measured by a compass. To calculate the deviation, the following formulas are used:

δ = MP - CP,

δ = WMD - OKP, (1)

δ = MK - KK

All methods for determining deviation differ only in the method of obtaining the magnitude of the magnetic bearing or heading. The main ways to determine deviation are:

- Determination of deviation along a target or along a fan of targets - is the most accurate way. The essence of the method is that at the moment of crossing the target, the compass bearing is noted.

The magnetic direction of the alignment is calculated based on the true direction and magnitude

The fan of alignments (Fig. 24) allows you to determine the deviation several times on the same course. The magnetic directions of the alignment fan are given in sailing directions or in descriptions of deviation polygons. If there are no alignments marked on the map in the area where the deviation is determined, then you can use the alignment of any objects (conspicuous towers, buildings, masts, capes, etc.). The magnetic direction of such a alignment is approximately calculated as the average of eight directions measured by compass on the main and quarter courses,

- Determining deviation from the bearing of a distant object carried out when there are no alignments in the work area. More often, this method is performed when the ship’s position does not change or changes slightly, i.e. when the vessel is moored on a deviation pole, barrels, etc. The magnitude of the magnetic bearing can be obtained from a chart if the ship's position is known with high accuracy. If this is not possible, the magnetic bearing is again calculated as the average of eight measured compass points at the main and quarter points according to formula (2). When a ship turns to a new course, its place on the ground does not remain constant, and at the same time the value of the MP changes. Obviously, the method can be used only when the change in bearing Δ from the average value does not exceed a certain permissible value. From Fig. 25 it can be seen that there is a relationship between the distance to the landmark D, the radius of the circle within which the position of the vessel (compass) changes, r and the angle Δ:

if you set Δ = 0.2°, then D = 300r. (3)

Thus, for example, with r = 100 m, the distance to the landmark must be at least 16.2 miles.

The method can also be used while the ship is moving, but in this case, a bearing on a distant object is taken at the moment when the ship passes in close proximity to a pre-installed buoy or pole. An approximate scheme of maneuvering when determining deviation using the indicated method is shown in Fig. 26.

Determination of deviation by comparison with the main magnetic compass usually carried out at a traveling compass, since there is no possibility of measuring bearing from it. The eight main and quarter courses are calculated using the heading compass, and the magnetic course is calculated using the CC of the main compass. The deviation of the traveling compass δп is obtained using the following formulas:

MK = KKgl + δgl. δp=MK - KKp (4)

or according to the working formula obtained after substituting the first equation into the second,

δp=KKgl - KKp+δgl. (5)

Comparison of compass readings, i.e. simultaneous fixation of the course, is carried out 3 - 5 times and the average value is displayed.

Determination of deviation from mutual bearings can be performed when there are no targets or distant objects in sight, but it is possible to take the compass ashore and install it on a tripod. The location where the compass is installed must ensure mutual visibility of the compass and the ship.

When determining deviation using any signal(lowering a conditioned signal flag, radio command, etc.) simultaneously measure the bearing from the shore and the ship. The bearing from the coast compass is MP + 180°, so it is easy to calculate the amount of deviation.

Determination of deviation by comparison with a gyrocompass- a common method on ships with a gyrocompass. The essence of the method is that the magnetic heading is obtained by determining the true one from the gyrocompass readings, and the declination is selected from the map. In the process of determining the deviation, the ship sequentially lies on eight main and quarter courses on the magnetic compass. On each course, the gyrocompass and magnetic compass courses are simultaneously noted (compared).

Deviation is calculated sequentially using the following formulas:

ik=gkk+Δgk,

MK = IR - d, δ = MK - KK

or according to the working formula obtained from them, (6)

δ = GKK-KK+(ΔGK - d),

where GKK n ΔGK is the gyrocompass heading and compass correction, respectively.

The comparison is performed 3–5 times, and the resulting deviations are averaged.

The method should be performed at the smallest speed, avoiding turns at a large angle, since this minimizes errors in the gyrocompass correction due to the influence of accelerations.

In addition to the methods discussed, a method for determining deviation is used according to the bearings of the heavenly bodies, if it is possible to measure the bearing of a star (Sun, Moon, star) and calculate its azimuth.

During sailing, it is necessary to use every opportunity to regularly determine the deviation on individual courses in order to monitor the reliability of the deviation table. To do this, they most often use definitions of compass corrections by alignments, by bearings of celestial bodies, and by comparison with a gyrocompass.

3.4. The principle of operation of the gyrocompass, taking into account errors in its readings. Methods for determining the gyrocompass correction.

The main heading guidance device is the gyrocompass. The basis of all gyroscopic direction indicators is a gyroscope (a rapidly rotating solid body), and the operation of these direction indicators is based on the property of the gyroscope to maintain the direction of the rotation axis in space unchanged without the action of moments of external forces.

The principle of operation of a gyrocompass can be described using a simplified diagram shown in Figure 27. The simplest gyrocompass consists of a gyroscope suspended inside a hollow ball that floats in a liquid; the weight of the ball with the gyroscope is such that its center of gravity is located on the axis of the ball in its lower part when the axis of rotation of the gyroscope is horizontal. Let's assume that the gyrocompass is located at the equator, and the axis of rotation of its gyroscope coincides with the west - east direction (position a); it maintains its orientation in space in the absence of external forces. But the Earth rotates, making one revolution per day. Since a nearby observer rotates with the planet, he sees the eastern end (E) of the gyroscope axis rising and the western end (W) descending; in this case, the center of gravity of the ball shifts to the east and upward (position b). However, the force of gravity prevents such a shift in the center of gravity, and as a result of its influence, the gyroscope axis rotates so as to coincide with the axis of the Earth’s daily rotation, i.e., with the north-south direction (this rotational movement of the gyroscope axis under the influence of an external force is called precession) . When the axis of the gyroscope coincides with the north-south direction (N-S, position c), the center of gravity will be in a lower position on the vertical and the cause of precession will disappear. By placing the “North” (N) mark on the place of the ball where the corresponding end of the gyroscope axis rests, and correlating the scale with the required divisions, you get a reliable compass. In a real gyrocompass, compensation for compass deviation and correction for latitude are provided. The action of the gyrocompass depends on the rotation of the Earth and the characteristics of the interaction of the gyroscope rotor with its suspension.

a) b) c)

Fig.27 Operating principle of the gyrocompass

To reduce the time of arrival at the meridian, gyrocompasses have a device for accelerated alignment to the meridian. If, using such a device, the SE of the main body is installed and held in the meridian with an accuracy of 2÷3°, then the time to reach the equilibrium position is reduced to 1÷1.5 hours (min 45 min.) The main axis of the SE of the working main body on a moving ship due to the presence dynamic and static errors are located in the direction of the gyroscopic meridian, which does not coincide with the true meridian.

Dynamic errors:

speed error, which arises due to the angular velocity of rotation of the true horizon plane due to the movement of the vessel along the surface of the Earth. This error is eliminated in the GC using a special counting and solving mechanism-corrector of the GC (by introducing IR, V, φ into it); inertial errors of the first and second kind, which arise when the course and speed of the vessel changes. At the end of the maneuver, the main body reaches a new equilibrium position in 25-30 minutes. These errors are eliminated in the HA by adjusting the period of undamped oscillations of the HA SE (84.3 min) and the use of an oil damper in the CE;

the error from pitching, which is caused by the swinging of the main body element relative to its main axis. Eliminated by stabilization of the SE in the horizontal plane.

Static errors: presence of friction in gyromotor suspensions; inconsistency of rotation speed of gyromotor rotors; inaccurate installation of the main device in the vessel's DP; action of magnetic fields. These errors, which characterize the stability of the operation of the hydraulic system on a fixed base, are determined experimentally. If it is possible to eliminate all of the indicated errors, then the main axis of the GC SE is set in the direction of the true meridian (NI), and the tracking system allows this direction to be directly recorded and transmitted to the GC repeaters. The guiding moment of the GC is many times greater than that of the MC and does not depend on the Earth's magnetic field. However, with increasing latitude (φ), it decreases in proportion to cos φ, and at high

at latitudes (> 75°) the HA works less reliably.