Ships and marine technology — Marine magnetic compasses, binnacles and azimuth reading devices

This document specifies requirements for the construction and performance of marine magnetic compasses for navigation and steering purposes, binnacles and azimuth reading devices. Two types of binnacle are specified; the appropriate type for a given vessel is determined by the design of the ship (see Clause 5). This document applies to liquid-filled magnetic compasses: — intended for use in ship's navigation and steering in sea navigation; — having a direct reading system; and — which can be of the reflecting, projecting or transmitting types. In the context of this document, a magnetic compass is an instrument consisting of a directional system supported by a single pivot inside a bowl that is completely filled with liquid and supported by gimbals inside or outside the bowl. However, this document also addresses compasses without gimbals; the requirements relating to gimbals do not apply to such compasses. This document applies to magnetic compasses carried on board: a) all ships required to carry a standard compass as per SOLAS Chapter V, the Class A magnetic compass; b) lifeboats and rescue boats as per the IMO Lifesaving Appliances (LSA) Code, fitted with the Class B magnetic compass; and c) all ships to which a) and b) above do not apply, but which are fitted with a Class A or B magnetic compass. This document does not apply to: a) dry card compasses; b) types of compass designed on principles different from those stated above or not complying with the descriptions given; or c) hand bearing compasses. The requirements for the testing and certification of marine magnetic compasses, azimuth reading devices and binnacles are given in Annexes A, B, C, and D. The requirements for the positioning in ships, the determination of safe distances and the deviation adjustment of compasses are given in Annexes E, F and G, respectively. The special requirements of the magnetic compass for lifeboats/rescue boats are given in Annex H.

Navires et structures maritimes — Compas magnétiques marins, habitacles et alidades

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Status
Published
Publication Date
11-Jul-2019
Current Stage
6060 - International Standard published
Start Date
12-Jul-2019
Completion Date
12-Jul-2019
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INTERNATIONAL ISO
STANDARD 25862
Second edition
2019-07
Ships and marine technology —
Marine magnetic compasses, binnacles
and azimuth reading devices
Navires et structures maritimes — Compas magnétiques marins,
habitacles et alidades
Reference number
ISO 25862:2019(E)
ISO 2019
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ISO 25862:2019(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2019

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

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Published in Switzerland
ii © ISO 2019 – All rights reserved
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ISO 25862:2019(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 2

4 Magnetic compasses ......................................................................................................................................................................................... 2

4.1 General ........................................................................................................................................................................................................... 2

4.1.1 Class A magnetic compass ....................................................................................................................................... 2

4.1.2 Class B magnetic compass ....................................................................................................................................... 2

4.2 Construction and materials .......................................................................................................................................................... 3

4.2.1 Magnetic material ........................................................................................................................................................... 3

4.2.2 Lubber mark ........................................................................................................................................................................ 3

4.2.3 Position of the card (class A only) ..................................................................................................................... 3

4.2.4 Angle of gimbal axes and intersection of vertical planes passing through them ..... 3

4.2.5 Thickness of the top glass cover (class A only) ..................................................................................... 3

4.2.6 Constructional condition within the temperature range .............................................................. 3

4.2.7 Horizontal position ........................................................................................................................................................ 4

4.3 Mounting ...................................................................................................................................................................................................... 4

4.3.1 Tilt of supporting device ........................................................................................................................................... 4

4.3.2 Freedom of the compass card with no supporting gimbal .......................................................... 4

4.4 Directional system ............................................................................................................................................................................... 4

4.4.1 Moment of inertia ........................................................................................................................................................... 4

4.4.2 Suspension (class A only) ......................................................................................................................................... 4

4.4.3 Magnetic moment ........................................................................................................................................................... 4

4.4.4 Settling time ......................................................................................................................................................................... 5

4.4.5 Tilt of the directional system with regard to the vertical field (class A only) ............. 5

4.4.6 Supporting force (class A only) ........................................................................................................................... 6

4.5 Compass card ........................................................................................................................................................................................... 6

4.5.1 Graduation ............................................................................................................................................................................. 6

4.5.2 Diameter of the card ..................................................................................................................................................... 6

4.5.3 Readability ............................................................................................................................................................................ 6

4.5.4 Bearing compasses ........................................................................................................................................................ 7

4.6 Accuracy ........................................................................................................................................................................................................ 7

4.6.1 Directional error .............................................................................................................................................................. 7

4.6.2 Error of lubber marks ........................................................................................................................................... ....... 7

4.6.3 Error due to friction ...................................................................................................................................................... 7

4.6.4 Swirl error ............................................................................................................................................................................. 8

4.6.5 Induction error (class A only) .............................................................................................................................. 8

4.6.6 Mounting error of azimuth reading device ............................................................................................... 8

4.6.7 Error due to eccentricity of the verge ring (class A only)............................................................. 8

4.7 Environmental conditions tests of magnetic compasses (class A only) ................................................ 8

5 Binnacles ...................................................................................................................................................................................................................... 9

5.1 General ........................................................................................................................................................................................................... 9

5.2 Binnacle type A1 .................................................................................................................................................................................... 9

5.2.1 General...................................................................................................................................................................................... 9

5.2.2 Construction and materials .................................................................................................................................... 9

5.2.3 Provision for correction of deviation (if combined with class B compasses) ............. 9

5.2.4 Accuracy of fore and aft marks .........................................................................................................................11

5.2.5 Illumination .......................................................................................................................................................................11

5.2.6 Environmental conditions requirements (class A only) .............................................................11

5.3 Binnacle type A2 .................................................................................................................................................................................11

5.3.1 General...................................................................................................................................................................................11

5.3.2 Construction and materials .................................................................................................................................11

5.3.3 Provision for correction of deviation ..........................................................................................................11

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ISO 25862:2019(E)

5.3.4 Accuracy of fore and aft marks .........................................................................................................................12

5.3.5 Illumination .......................................................................................................................................................................13

5.3.6 Environmental conditions requirements (class A only) .............................................................13

6 Azimuth reading devices ...........................................................................................................................................................................13

6.1 General ........................................................................................................................................................................................................13

6.2 Azimuth sight ........................................................................................................................................................................................13

6.3 Azimuth reading devices with vanes ................................................................................................................................13

6.4 Level ..............................................................................................................................................................................................................13

7 Marking .......................................................................................................................................................................................................................13

8 Designation .............................................................................................................................................................................................................14

Annex A (normative) Testing and certification of marine magnetic compasses, binnacles

and azimuth reading devices — General requirements ...........................................................................................15

Annex B (normative) Testing and certification of marine magnetic compasses .................................................17

Annex C (normative) Testing and certification of azimuth reading devices ............................................................27

Annex D (normative) Type-testing and certification of binnacles .....................................................................................32

Annex E (normative) Positioning of magnetic compasses in ships ...................................................................................40

Annex F (normative) Determination of safe distances ...................................................................................................................45

Annex G (normative) Adjustment of magnetic compass deviation ....................................................................................46

Annex H (normative) Requirements of magnetic compass for lifeboats/rescue boats ...............................48

Bibliography .............................................................................................................................................................................................................................49

iv © ISO 2019 – All rights reserved
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ISO 25862:2019(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso

.org/iso/foreword .html.

This document was prepared by Technical Committee ISO/TC 8, Ships and marine technology,

Subcommittee SC 6, Navigation and ship operations.

This second edition cancels and replaces the first edition (ISO 25862:2009), which has been technically

revised.
The main changes compared to the previous edition are as follows:
— Clause 1: an overview of the annexes was added.
— Clause 2: moved IMO Resolution A. 382 (X) to the Bibliography.
— Clause 3: 3.4 and 3.5 were added.

— Clause 4: 4.1 was added. The temperature range of Class B magnetic compasses was changed to

“−30 °C to +60 °C” (4.2.6). The magnetic moment of Class B magnetic compasses was added to

Figure 1. Table 2 was updated (Equal interval of the graduation of Class B magnetic compasses was

changed to “1°, 2°, 2,5° or 5°”. Card numbered of Class B magnetic compasses was changed to “Every

30° or every 10°”.) and 4.7 was updated.
— Clause 5: 5.1, 5.2.1, and 5.3.1 were added. 5.2.6 and 5.3.6 were updated.
— Clause 6: 6.1 was added.
— Annex D: D.2.4.1 and D.2.6.1 were added.
— Annex H: H.2.1 was added.
— Bibliography: IMO Resolution A. 382 (X) and EN 166 were added.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/members .html.
© ISO 2019 – All rights reserved v
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INTERNATIONAL STANDARD ISO 25862:2019(E)
Ships and marine technology — Marine magnetic
compasses, binnacles and azimuth reading devices
1 Scope

This document specifies requirements for the construction and performance of marine magnetic

compasses for navigation and steering purposes, binnacles and azimuth reading devices.

Two types of binnacle are specified; the appropriate type for a given vessel is determined by the design

of the ship (see Clause 5).
This document applies to liquid-filled magnetic compasses:
— intended for use in ship's navigation and steering in sea navigation;
— having a direct reading system; and
— which can be of the reflecting, projecting or transmitting types.

In the context of this document, a magnetic compass is an instrument consisting of a directional system

supported by a single pivot inside a bowl that is completely filled with liquid and supported by gimbals

inside or outside the bowl. However, this document also addresses compasses without gimbals; the

requirements relating to gimbals do not apply to such compasses.
This document applies to magnetic compasses carried on board:

a) all ships required to carry a standard compass as per SOLAS Chapter V, the Class A magnetic

compass;

b) lifeboats and rescue boats as per the IMO Lifesaving Appliances (LSA) Code, fitted with the Class B

magnetic compass; and

c) all ships to which a) and b) above do not apply, but which are fitted with a Class A or B magnetic

compass.
This document does not apply to:
a) dry card compasses;

b) types of compass designed on principles different from those stated above or not complying with

the descriptions given; or
c) hand bearing compasses.

The requirements for the testing and certification of marine magnetic compasses, azimuth reading

devices and binnacles are given in Annexes A, B, C, and D. The requirements for the positioning in ships,

the determination of safe distances and the deviation adjustment of compasses are given in Annexes E,

F and G, respectively. The special requirements of the magnetic compass for lifeboats/rescue boats are

given in Annex H.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 1069, Magnetic compasses and binnacles for sea navigation — Vocabulary
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ISO 25862:2019(E)

lEC 60945, Maritime navigation and radiocommunication equipment and systems — General

requirements — Methods of testing and required test results
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 1069 and the following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
magnetic control sensor

sensor using the geomagnetic field for feeding an automatic heading-control system, or controlling an

off-course alarm unit, or feeding other devices
3.2
minimum distance

distance measured between the nearest point of magnetic material which is part of the ship's structure

and the centre of the compass

Note 1 to entry: The minimum distance for a standard compass is given in Figure E.1 and for a steering compass

is given in Figure E.2.
3.3
safe distance

distance measured between the nearest point of the item concerned and the centre of the compass

Note 1 to entry: The safe distance is determined as specified in Annex F.
3.4
settling time

time taken to return finally to within ±1° of the magnetic meridian after an initial deflection of 90°

from that meridian
3.5
pelorus

device used for taking bearings of distant objects or the sun, which are obscured from view at the

compass position and whose altitudes are between 5° below and 30° above the horizontal

4 Magnetic compasses
4.1 General
4.1.1 Class A magnetic compass
— intended for ship's navigation and steering purposes in sea navigation;
— liquid-filled magnetic compass, with or without gimbals; and

— having a direct reading system, which can be of the reflecting, projecting or transmitting types.

4.1.2 Class B magnetic compass

— intended for sea navigation on board ships for "restricted service, lifeboats or rescue boats";

— liquid-filled magnetic compasses, with or without gimbals; and
2 © ISO 2019 – All rights reserved
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ISO 25862:2019(E)

— having a direct reading system; which can be of the reflecting, projecting or transmitting types.

4.2 Construction and materials
4.2.1 Magnetic material

The magnets used in the directional systems of magnetic compasses shall be of a suitable magnetic

material having a high remanence and coercivity of at least 18 kA/m. All other fixtures used in magnetic

compasses, other than transmitting compasses, shall be made of non-magnetic material.

4.2.2 Lubber mark

In class A compasses, the distance between the lubber mark and the outer edge of the card shall be

between 1,5 mm and 3,0 mm for direct reading and reflecting types and between 0,5 mm and 1,5 mm

for projecting compasses. The width of the lubber mark shall not be greater than 0,5° of the graduation

of the card.

In class B compasses, the compass shall be fitted with at least one lubber mark, indicating the direction

of the ships head (the main lubber mark). Additional lubber marks are permissible.

The lubber mark shall be of such design as to allow the compass to be read from the steering position

when the bowl is tilted 10° in the case of a gimbal compass or 30° in other cases.

4.2.3 Position of the card (class A only)

When the verge ring and the seating for the azimuth reading device are both horizontal, the graduated

edge of the card, the lubber mark if a point, the pivot point and the outer gimbal axis shall lie within

1 mm of the horizontal plane passing through the gimbal axis fixed to the bowl.

4.2.4 Angle of gimbal axes and intersection of vertical planes passing through them

The angle formed by the outer and inner gimbal axes shall be of the values given in Table 1. The vertical

planes through the gimbal axes shall intersect to within 1 mm of the pivot point. Any end play shall not

cause these tolerances to be exceeded.
Table 1 — Angle of gimbal axes
Magnetic compasses Angle of gimbal axes
Class A (90 ± 1)°
Class B (90 ± 2)°

The outer gimbal axis shall be in the fore and aft direction. For compasses without gimbals, which are

also covered by this document, the requirements relating to gimbals do not apply.

4.2.5 Thickness of the top glass cover (class A only)

The thickness of the top glass cover and of the bottom glass of the compass shall be not less than

4,5 mm, if non-toughened, and not less than 3,0 mm, if toughened. These values do not apply to the

thickness of the top glass in hemispherical compasses. If material other than glass is used, it shall fulfil

the requirement of B.1 d).
4.2.6 Constructional condition within the temperature range

All class A and class B compasses shall operate satisfactorily throughout the temperature range −30 °C

to +60 °C, and:

a) the liquid in the compass bowl shall remain clear and free from bubbles and neither emulsify

nor freeze;
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ISO 25862:2019(E)

b) there shall be neither inward leakage of air nor outward leakage of liquid. No bubble shall form

in a compass unless it is specially provided to compensate for expansion. A bubble provided in a

compass to compensate for expansion shall not inconvenience the functioning and reading of the

compass;
c) the internal paint shall not blister, crack or discolour appreciably;

d) the supporting force shall be such that the directional system always remains in contact with

its pivot;
e) the material of the compass card shall not distort.
4.2.7 Horizontal position

The compass bowl shall be balanced so that its verge ring or top glass cover settles within 2° of the

horizontal plane when the gimbal ring is fixed in a horizontal position; this shall be so with, or without,

an azimuth reading device or magnifying glass is in place.
4.3 Mounting
4.3.1 Tilt of supporting device

The bowl of the compass shall be mounted in such a manner that the compass cannot be dislodged

under any conditions of sea or weather and so that the verge ring remains within 2° of the horizontal

plane when the binnacle is tilted in any direction to a maximum of:
a) 40° for class A compasses, and
b) 30° for class B compasses.
The inner and outer gimbal bearings shall be of the same type.
4.3.2 Freedom of the compass card with no supporting gimbal

In compasses in which no supporting gimbal is provided, the card shall be free to move at least 30° in

all directions.
4.4 Directional system
4.4.1 Moment of inertia

The moment of inertia of the directional system shall be approximately the same about all horizontal

axes passing through the point of support on the pivot jewel.
4.4.2 Suspension (class A only)

The directional system shall be retained in position by suitable means and remain free when the bowl

is tilted 10° in any direction.
4.4.3 Magnetic moment

The magnetic moment of the magnets in the directional system shall not be less than the value given in

Figure 1.
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ISO 25862:2019(E)
Key
X card diameter, expressed in mm
Y magnetic moment, expressed in A·m
class A magnetic compass
class B magnetic compass
Figure 1 — Magnetic moment of liquid filled compasses (minimum requirements)
4.4.4 Settling time

The settling time of a directional system shall not exceed 240/ H s at a temperature of (20 ± 3) °C,

where H is the horizontal component of the magnetic flux density in microteslas (µT) at the place of

testing.

4.4.5 Tilt of the directional system with regard to the vertical field (class A only)

The directional system shall be so constructed, or balanced in such a way, that it does not incline more

than 0,5° from the horizontal plane when the vertical flux density is zero. The inclination shall not

change by more than 3° when the vertical flux density changes by 100 μT.
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ISO 25862:2019(E)
4.4.6 Supporting force (class A only)

The force exerted on the pivot bearing, in the liquid used at a temperature of (20 ± 3) °C, by the

directional system shall be between 0,04 N and 0,14 N.
4.5 Compass card
4.5.1 Graduation

The compass card shall be graduated in 360 single degrees, starting from North in the clockwise

direction as viewed from above. The marks shall be at intervals as given in Table 2. In addition, as given

in Table 2, at least every ten degrees (class A) and every ten or thirty degrees (class B) shall be marked

with their corresponding three figure number (e.g. 030). North shall be indicated by “000°”.

The cardinal points shall be indicated by the capital letters “N”, “S”, “E” and “W”; the intermediate points

may also be marked. Alternatively, the North point may be indicated by a suitable symbol.

Table 2 — Graduation of the card
Magnetic compasses Equal interval of the graduation Card numbered
Class A 1° Every 10°
Every 30°or
Class B 1°, 2°, 2,5° or 5°
every 10°

Where the compass card is printed on both sides, the graduations shall coincide with a tolerance of 0,2°.

4.5.2 Diameter of the card
The diameter of the compass cards shall be as given in Table 3.
Table 3 — Diameter of the card
Magnetic compasses Binnacle types Diameter of the card
A1 165 mm or more
Class A
A2 125 mm or more
Class B 125 mm or more
NOTE 1 Binnacle types are defined in 5.2 (Type A1) and 5.3 (Type A2).

NOTE 2 The required diameter of a compass card for use in lifeboats/rescue boats is given

in H.2.2.
4.5.3 Readability

Steering compasses of each class shall be able to be read by a person with normal vision at a distance

from the magnetic compasses as given in Table 4 in both daylight and artificial light, the graduations

on the card being contained within a sector whose width is not less than 15° to each side

...

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