ISO/FDIS 8728

Ships and marine technology — Marine gyro-compasses

Navires et technologie maritime — Compas gyroscopiques à usage marin

General Information

• Status: Not Published
• ICS: 47.020.70 - Navigation and control equipment
• Technical Committee: ISO/TC 8/SC 6 - Navigation and ship operations
• Drafting Committee: ISO/TC 8/SC 6 - Navigation and ship operations
• Current Stage: 5020 - FDIS ballot initiated: 2 months. Proof sent to secretariat
• Start Date: 11-Sep-2023
• Completion Date: 11-Sep-2023

Relations

• Revises: ISO 8728:2014 - Ships and marine technology — Marine gyro-compasses
• Effective Date: 06-Jun-2022

Standards Content (Sample)

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 8728
ISO/TC 8/SC 6
Ships and marine technology —
Secretariat: JISC
Marine gyro-compasses
Voting begins on:
2023-09-11
Navires et technologie maritime — Compas gyroscopiques à usage
marin
Voting terminates on:
2023-11-06
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 8728:2023(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS. © ISO 2023

---------------------- Page: 1 ----------------------
ISO/FDIS 8728:2023(E)
FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 8728
ISO/TC 8/SC 6
Ships and marine technology —
Secretariat: JISC
Marine gyro-compasses
Voting begins on:
Navires et technologie maritime — Compas gyroscopiques à usage
marin
Voting terminates on:
COPYRIGHT PROTECTED DOCUMENT
© ISO 2023
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 on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
RECIPIENTS OF THIS DRAFT ARE INVITED TO
ISO copyright office
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
CP 401 • Ch. de Blandonnet 8
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
CH-1214 Vernier, Geneva
DOCUMENTATION.
Phone: [phone]
IN ADDITION TO THEIR EVALUATION AS
Reference number
Email: [e-mail]
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
ISO/FDIS 8728:2023(E)
Website: www.iso.org
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
Published in Switzerland
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN­
DARDS TO WHICH REFERENCE MAY BE MADE IN
ii
  © ISO 2023 – All rights reserved
NATIONAL REGULATIONS. © ISO 2023

---------------------- Page: 2 ----------------------
ISO/FDIS 8728:2023(E)
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Abbreviated terms . 3
5 Construction requirements . 4
6 Performance requirements . .5
6.1 Accuracy in latitudes up to 60° . 5
6.1.1 Settling time . 5
6.1.2 Settle point error . 5
6.1.3 Settling time under operational conditions . 5
6.1.4 Settle point error under general conditions . 5
6.1.5 Residual error in correction. 5
6.1.6 Effect of alteration of speed. 5
6.1.7 Effect of alteration of course . 5
6.1.8 Accuracy on a Scorsby table . 6
6.1.9 Synchronization between the master compass and repeaters . 6
6.2 Interface . 6
6.3 Alert management . 6
6.3.1 General . 6
6.3.2 Power failure in the gyro-compass (“GC power fail” alert) . 6
6.3.3 Malfunction of the gyro-compass system (“System fault” alert) . 7
7 Type tests . 7
7.1 General . 7
7.2 Settling time test . 7
7.3 Settle point error test . 7
7.4 Settle point heading repeatability test . 7
7.5 Settling time on a Scorsby table . 8
7.6 Scorsby test. 8
7.7 Intercardinal motion test . 8
7.8 Repeater accuracy test . 9
7.9 Speed correction test . 9
7.10 General requirement test . 9
7.10.1 General . 9
7.10.2 Voltage variation test . 10
7.10.3 Frequency variation test . 10
7.10.4 Vibration tests . 10
7.10.5 Temperature test . . 11
7.10.6 Damp heat test . . 11
7.10.7 Other tests . 11
7.11 Interface test .12
7.12 Alert management test .12
7.12.1 Basic test for alert management .12
7.12.2 “Power fail” alert or output of a status signal on the EUT power .12
7.12.3 “System fault” alert .12
8 Marking . .13
9 Information .13
Annex A (normative) Requirements for ship surveyors for the installation of gyro-
compasses and repeater compasses on board ships .14
iii
© ISO 2023 – All rights reserved

---------------------- Page: 3 ----------------------
ISO/FDIS 8728:2023(E)
Annex B (normative) Alerts definition for gyro-compasses .15
Annex C (normative) IEC 61162 interfaces for VDR and other external equipment .16
Bibliography .18
iv
  © ISO 2023 – All rights reserved

---------------------- Page: 4 ----------------------
ISO/FDIS 8728:2023(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 non­governmental, 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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use
of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed
patent rights in respect thereof. As of the date of publication of this document, ISO had not received
notice of (a) patent(s) which may be required to implement this document. However, implementers are
cautioned that this may not represent the latest information, which may be obtained from the patent
database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all
such patent rights.
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 fourth edition cancels and replaces the third edition (ISO 8728:2014), which has been technically
revised.
The main changes are as follows:
— Clause 4 (abbreviated terms) has been added;
— in 6.3, requirements related to bridge alert management have been added;
— in 7.1, a requirement for display equipment has been added;
— in 7.12, test method for requirements related to bridge alert management has been added;
— in Annex B, the equivalent requirements in ISO 8728 and IMO Resolution have been deleted and the
alerts with a standard alert identifier have been defined;
— in Annex C, IEC 61162 interfaces overview has been added;
— the normative references and bibliography have been updated.
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.
v
© ISO 2023 – All rights reserved

---------------------- Page: 5 ----------------------
ISO/FDIS 8728:2023(E)
Introduction
This document is aligned with IMO Resolution A.424(XI) on performance standards for gyro-compasses.
Any text in this document which is a citation from the IMO Resolution A.424(XI), appears in italics.
Within these citations, any changes to the original wording of the IMO Resolution A.424(XI) are written
in upright font.
In this document, the following verbal forms are used:
— “shall” indicates a requirement;
— “should” indicates a recommendation;
— “may” indicates a permission;
— “can” indicates a possibility or a capability.
vi
  © ISO 2023 – All rights reserved

---------------------- Page: 6 ----------------------
FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 8728:2023(E)
Ships and marine technology — Marine gyro-compasses
1 Scope
This document specifies the construction, performance, and type testing for gyro-compasses which
are required by the International Convention for the Safety of Life at Sea (SOLAS), 1974 (as amended),
Chapter V, Regulation 19.
This document specifies the minimum requirements, the construction, performance, and type testing
for gyro-compasses, which required to comply with the performance standards adopted by the IMO
Resolution A.424(XI).
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.
IEC 60945, Maritime navigation and radiocommunication equipment and systems — General requirements
— Methods of testing and required test results
IEC 61162­1, Marine navigation and radiocommunication equipment and systems — Digital interfaces -
Part 1: Single talker and multiple listeners
IEC 61162­2, Maritime navigation and radiocommunication equipment and systems — Digital interfaces —
Part 2: Single talker and multiple listeners, high-speed transmission
IEC 61162­450, Maritime navigation and radiocommunication equipment and systems - Digital interfaces -
Part 450: Multiple talkers and multiple listeners - Ethernet interconnection
IEC 62288, Maritime navigation and radiocommunication equipment and systems — Presentation of
navigation-related information on shipborne navigational displays — General requirements, methods of
testing and required test results
IEC 62923­1:2018, Maritime navigation and radiocommunication equipment and systems — Bridge alert
management — Part 1: Operational and performance requirements, methods of testing and required test
results
IEC 62923­2, Maritime navigation and radiocommunication equipment and systems — Bridge alert
management — Part 2: Alert and cluster identifiers and other additional features
IMO Resolution MSC 302(87), Performance standards for bridge alert management
IMO Resolution MSC 191(79), Performance standards for the presentation of navigation-related
information on shipborne navigational displays
IMO Resolution MSC 466(101), Amendments to the performance standards for the presentation of
navigation-related information on shipborne navigational displays (Resolution MSC.191(79))
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
1
© ISO 2023 – All rights reserved

---------------------- Page: 7 ----------------------
ISO/FDIS 8728:2023(E)
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
gyro-compass
complete equipment comprising all essential elements of the complete design, including both the gyro-
compass as heading sensor and the associated heading transmission system
[SOURCE: IMO Resolution A.424(XI), 2.1, modified — elements of complete design have been specified.]
3.2
true heading
horizontal angle between the vertical plane passing through the true meridian and the vertical plane
passing through the ship’s fore­and­aft datum line
Note 1 to entry: The true heading is measured from true north (000°) clockwise through 360°.
Note 2 to entry: When the gyro-compass equipment is not installed on board ship, this “true heading” is regarded
as the true heading of the lubber line. Where a gyro-compass has the facility of introducing a correction by
moving the lubber line, the correction is set for the local latitude.
[SOURCE: IMO Resolution A.424(XI), 2.2, modified — notes 1 and 2 to entry have been added.]
3.3
settled
stable situation when any three readings taken at intervals of 30 min are within a band of 0,7°, with the
compass level and stationary
Note 1 to entry: The settling time is the elapsed time between the time of switch-on at the initial heading error
and the third recording of the settle.
[SOURCE: IMO Resolution A.424(XI), 2.3, modified — note 1 to entry has been added.]
3.4
settle point heading
mean value of ten readings taken at 20 min intervals after the compass has settled (3.3)
[SOURCE: IMO Resolution A.424(XI), 2.4]
3.5
settle point error
difference between the settle point heading (3.4) and the true heading (3.2)
[SOURCE: IMO Resolution A.424(XI), 2.5]
3.6
error
difference between the observed value and the settle point heading (3.4)
[SOURCE: IMO Resolution A.424(XI), 2.6]
3.7
repeater compass
device that reproduces the master compass card at a remote location
3.8
bearing repeater compass
device that reproduces the master compass card for the purpose of taking bearings
3.9
compass card
graduated dial of the compass which indicates the measured direction of the meridian
2
  © ISO 2023 – All rights reserved

---------------------- Page: 8 ----------------------
ISO/FDIS 8728:2023(E)
3.10
latitude error
error (3.6) to which some gyro-compasses (3.1) are subject, the magnitude and sign of which depend
upon the local latitude
Note 1 to entry: Means are provided for correcting this error.
3.11
speed error
error (3.6) to which gyro-compasses (3.1) are subject, the magnitude and sign of which depend upon the
speed, course, and latitude of the ship
Note 1 to entry: Means are provided for correcting this error.
3.12
lubber line
index line situated on the body of a compass against which the compass heading is read
3.13
master compass
main compass unit which supplies the heading information to the repeaters and other navigational aids
3.14
Scorsby table
test machine which enables a platform to oscillate independently about three axes
Note 1 to entry: It is used to simulate the motion of a ship.
3.15
bridge alert management
BAM
overall concept for management, handling and harmonized presentation of alerts on the bridge
[SOURCE: IMO Resolution MSC.302(87), Appendix 1]
3.16
central alert management system
CAM system
combined functionality of the central alert management and the central alert management human
machine interface
[SOURCE: IMO Resolution MSC.302(87), Appendix 1]
4 Abbreviated terms
For the purposes of this document, the following abbreviated terms apply.
BAM bridge alert management
CAM central alert management
EUT equipment under test
GC gyro-compass
GNSS global navigation satellite system
SDME speed and distance measuring system
VDR Voyage Data Recorder
3
© ISO 2023 – All rights reserved

---------------------- Page: 9 ----------------------
ISO/FDIS 8728:2023(E)
5 Construction requirements
Gyro-compass units shall conform to the following requirements.
a) In accordance with IMO Resolution A.424(XI), 6.1 and 8, the equipment shall be capable of continuous
operation under conditions of vibration, humidity, change of temperature and variations of the power
supply as specified in 7.10.2 to 7.10.6.
b) For ships which are required to carry bearing repeater compasses, the construction of these shall
be as follows.
1) The bearing repeater compass shall be designed to be fitted with an azimuth reading device.
2) A gimbal mechanism shall be provided to enable the bearing repeater compass card to be held
horizontally against the ship's motion.
3) Any bearing repeater compass intended for use on an open deck shall be waterproof.
c) In accordance with IMO Resolution A.424(XI), 3, the compass card shall be graduated at equal
intervals of 1° or fraction thereof.
The graduation error shall be less than ±0,2°.
A numerical indication shall be provided at least at every 10°, starting from 000° clockwise through
360°.
d) In accordance with IMO Resolution A.424(XI), 4, fully adequate illumination shall be provided to
enable the reading of all compass cards at all times. Facilities for dimming shall be provided.
e) Both master compass and repeater compasses shall be provided with a lubber line to indicate the
ship’s heading.
The base or some other fixed extremity of the compass shall be marked or identified in such a way
as to facilitate the installation of the compass in a ship, so that the lubber line lies in a vertical
fore-and-aft plane of the ship. Where a gyro-compass has the facility of introducing a correction
by moving the lubber line, the correction during installation shall be set to zero. If such marks or
identifications are not in the same vertical planes as the uncorrected lubber line, then the horizontal
angular relationship between them shall be clearly indicated.
f) In accordance with IMO Resolution A.424(XI), 9.1, the master compass and any repeaters used
for taking visual bearings shall be installed or adjusted in a ship with their fore and aft datum lines
parallel to the ship's fore and aft datum line to within ±0,5°. The lubber line shall be in the same vertical
plane passing through the centre of the card of the compass and shall be aligned accurately in the fore
and aft direction.
Requirements for ship surveyors for installation of gyro-compasses and repeater compasses on
board ships shall be in accordance with Annex A.
g) In accordance with IMO Resolution A.424(XI), 9.2, means shall be provided for correcting the errors
induced by speed and latitude. Graphical or tabular means of correction can be used.
h) In accordance with IMO Resolution A.424(XI), 7.1, steps shall be taken to eliminate as far as is
practicable, the causes of, and to suppress, electromagnetic interference between the gyro-compass
and other equipment on board.
i) In accordance with IMO Resolution A.424(XI), 7.2, mechanical noise from all units shall be so limited
as to ensure the hearing of sounds on which the safety of the ship may depend.
j) In accordance with IMO Resolution A.424(XI), 9.7, the equipment shall be so constructed that it is
readily accessible for maintenance purposes.
4
  © ISO 2023 – All rights reserved

---------------------- Page: 10 ----------------------
ISO/FDIS 8728:2023(E)
k) In accordance with IMO Resolution A.424(XI), 6.2, means shall be incorporated for the protection of
the equipment from excessive currents and voltages, transients and accidental reversal of power supply
polarity.
l) In accordance with IMO Resolution A.424(XI), 6.3, if provision is made for operating the equipment
from more than one source of electrical energy, arrangements for rapidly changing from one source of
supply to the other shall be incorporated.
m) In accordance with IMO Resolution A.424(XI), 9.4, the gyro-compass shall be designed to enable
heading information to be provided to other navigational aids. See 6.2.
6 Performance requirements
6.1 Accuracy in latitudes up to 60°
6.1.1 Settling time
In accordance with IMO Resolution A.424(XI), 5.1.1, when switched on in accordance with the
manufacturer's instructions, the compass shall settle within 6 h.
6.1.2 Settle point error
In accordance with IMO Resolution A.424(XI), 5.1.2, the settle point error at any heading shall not
exceed ± 0,75° × secant latitude, and the RMS value of the differences between individual heading indications
and the mean value shall be less than 0,25° × secant latitude. The repeatability of settle point error from
one run-up to another shall be within 0,25° × secant latitude.
6.1.3 Settling time under operational conditions
In accordance with IMO Resolution A.424(XI), 5.2.1, when switched on in accordance with the
manufacturer's instructions, the compass shall settle within 6 h when rolling and pitching with simple
harmonic motion of any period between 6 s and 15 s, a maximum angle of 5°, and a maximum horizontal
2
acceleration of 0,22 m/s .
6.1.4 Settle point error under general conditions
In accordance with IMO Resolution A.424(XI), 5.2.2, the repeatability of the settle point error of the
master compass shall be within ±1° × secant latitude under the general conditions and including variations
in magnetic fields likely to be experienced in the ship in which it is installed.
6.1.5 Residual error in correction
In accordance with IMO Resolution A.424(XI), 5.2.3.1, the residual steady-state error, after correction for
1)
speed and course influences at a speed of 20 kn , shall not exceed ±0,25° × secant latitude.
6.1.6 Effect of alteration of speed
In accordance with IMO Resolution A.424(XI), 5.2.3.2, the error due to a rapid alteration of speed of
1)
20 kn shall not exceed ±2°.
6.1.7 Effect of alteration of course
In accordance with IMO Resolution A.424(XI), 5.2.3.3, the error due to a rapid alteration of course of 180°
1)
at a speed of 20 kn shall not exceed ±3°.
1) 1 kn = 1,852 km/h.
5
© ISO 2023 – All rights reserved

---------------------- Page: 11 ----------------------
ISO/FDIS 8728:2023(E)
6.1.8 Accuracy on a Scorsby table
In accordance with IMO Resolution A.424(XI), 5.2.3.4, the transient and steady-state errors due to rolling,
pitching, and yawing, with simple harmonic motions of any period between 6 s and 15 s, maximum angles
2
of 20°, 10°, and 5° respectively, and a maximum horizontal acceleration not exceeding 1 m/s , shall not
exceed ± 1° × secant latitude.
6.1.9 Synchronization between the master compass and repeaters
In accordance with IMO Resolution A.424(XI), 5.2.4, once the repeaters have been synchronized with
the master, the maximum divergence in reading between the master compass and repeaters under all
operational condit
...

ISO/FDIS 8728:2023(E)
Style Definition: Heading 1: Indent: Left: 0 pt, First
line: 0 pt, Tab stops: Not at 21.6 pt
ISO TC 8/SC 6
Style Definition: Heading 2: Font: Bold, Tab stops: Not
at 18 pt
Secretariat: JISC
Style Definition: Heading 3: Font: Bold
Date: 2023-07-0308-28
Style Definition: Heading 4: Font: Bold
Style Definition: Heading 5;h5: Font: Bold
Ships and marine technology — Marine gyro-compasses
Style Definition: Heading 6;h6: Font: Bold
Navires et technologie maritime — Compas gyroscopiques à usage marin
Style Definition: ANNEX
Style Definition: AMEND Terms Heading: Font: Bold
Style Definition: AMEND Heading 1 Unnumbered:
Font: Bold
Style Definition: ハッシュタグ1
Style Definition: メンション1
Style Definition: スマート ハイパーリンク1
Style Definition: 未解決のメンション1
Style Definition: IneraTableMultiPar: Font: Not Bold,
Italic, Justified, Don't adjust space between Latin and
Asian text, Don't adjust space between Asian text and
numbers
Formatted: English (United States)
Formatted: English (United States)
Formatted: Font: Bold

---------------------- Page: 1 ----------------------
© ISO 2023 Formatted
Formatted: Default Paragraph Font
All rights reserved. Unless otherwise specified, or required in the context of its implementation,
Formatted: Default Paragraph Font
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 on the internet or an intranet,
Formatted: No page break before, Adjust space
without prior written permission. Permission can be requested from either ISO at the address between Latin and Asian text, Adjust space between
below or ISO’sISO's member body in the country of the requester. Asian text and numbers
Formatted: Adjust space between Latin and Asian text,
ISO copyright officeCopyright Office
Adjust space between Asian text and numbers
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Formatted: Adjust space between Latin and Asian text,
Adjust space between Asian text and numbers
Phone: + 41 22 749 01 11
Email: [e-mail]
Email: [e-mail]
Website: www.iso.orgwww.iso.org
Formatted: Adjust space between Latin and Asian text,
Adjust space between Asian text and numbers
Published in Switzerland.

---------------------- Page: 2 ----------------------
ISO/FDIS 8728:2023(E)
Contents
Foreword . 5
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Abbreviated terms . 4
5 Construction requirements . 4
6 Performance requirements . 5
6.1 Accuracy in latitudes up to 60° . 5
6.1.1 Settling time . 5
6.1.2 Settle point error . 5
6.1.3 Settling time under operational conditions . 6
6.1.4 Settle point error under general conditions . 6
6.1.5 Residual error in correction . 6
6.1.6 Effect of alteration of speed . 6
6.1.7 Effect of alteration of course . 6
6.1.8 Accuracy on a Scorsby table . 6
6.1.9 Synchronization between the master compass and repeaters . 6
6.2 Interface . 6
6.3 Alert management . 7
6.3.1 General . 7
6.3.2 Power failure in the gyro-compass ("GC power fail" alert) . 7
6.3.3 Malfunction of the gyro-compass system ("System fault" alert) . 7
7 Type tests . 7
7.1 General . 7
7.2 Settling time test . 8
7.3 Settle point error test . 8
7.4 Settle point heading repeatability test . 8
7.5 Settling time on a Scorsby table . 8
7.6 Scorsby test . 8
7.7 Intercardinal motion test . 9
7.8 Repeater accuracy test . 9
7.9 Speed correction test . 10
7.10 General requirement test . 10
7.10.1 General . 10
7.10.2 Voltage variation test . 10
7.10.3 Frequency variation test . 10
7.10.4 Vibration tests . 11
7.10.5 Temperature test . 12
7.10.6 Damp heat test . 12
7.10.7 Other tests . 12
7.11 Interface test . 12
7.12 Alert management test . 13
7.12.1 Basic test for alert management . 13
ii © ISO 2023 – All rights reserved

---------------------- Page: 3 ----------------------
ISO/FDIS 8728:2023(E)
7.12.2 "Power fail" alert or output of a status signal on the EUT power . 13
7.12.3 "System fault" alert . 13
8 Marking . 13
9 Information . 13
Annex A (normative)  Advice to for ship surveyors for installation of gyro-compasses and
repeater compasses on board ships . 14
Annex B (normative) Alerts definition for gyro-compasses . 15
Annex C (normative) IEC 61162 interfaces for VDR and the other external equipment . 16
Bibliography . 19
Foreword . v
Introduction . vii
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Abbreviated terms . 4
5 Construction requirements . 4
6 Performance requirements . 5
6.1 Accuracy in latitudes up to 60°. 5
6.1.1 Settling time . 5
6.1.2 Settle point error . 5
6.1.3 Settling time under operational conditions . 6
6.1.4 Settle point error under general conditions . 6
6.1.5 Residual error in correction . 6
6.1.6 Effect of alteration of speed . 6
6.1.7 Effect of alteration of course . 6
6.1.8 Accuracy on a Scorsby table . 6
6.1.9 Synchronization between the master compass and repeaters . 6
6.2 Interface . 6
6.3 Alert management . 7
6.3.1 General . 7
6.3.2 Power failure in the gyro-compass (“GC power fail” alert) . 7
6.3.3 Malfunction of the gyro-compass system (“System fault” alert) . 7
7 Type tests . 7
7.1 General . 7
7.2 Settling time test . 8
7.3 Settle point error test . 8
7.4 Settle point heading repeatability test . 8
7.5 Settling time on a Scorsby table . 8
7.6 Scorsby test . 8
7.7 Intercardinal motion test . 9
7.8 Repeater accuracy test . 9
7.9 Speed correction test . 10
7.10 General requirement test . 10
7.10.1 General . 10
7.10.2 Voltage variation test . 10
7.10.3 Frequency variation test . 10
© ISO 2023 – All rights reserved iii

---------------------- Page: 4 ----------------------
ISO/FDIS 8728:2023(E)
7.10.4 Vibration tests . 11
7.10.5 Temperature test . 12
7.10.6 Damp heat test . 12
7.10.7 Other tests . 12
7.11 Interface test . 12
7.12 Alert management test . 13
7.12.1 Basic test for alert management . 13
7.12.2 “Power fail” alert or output of a status signal on the EUT power . 13
7.12.3 “System fault” alert. 13
8 Marking . 13
9 Information . 13
Annex A (normative) Requirements for ship surveyors for the installation of gyro-
compasses and repeater compasses on board ships . 14
Annex B (normative) Alerts definition for gyro-compasses . 15
Annex C (normative) IEC 61162 interfaces for VDR and other external equipment . 16
Bibliography . 19


iv © ISO 2023 – All rights reserved

---------------------- Page: 5 ----------------------
ISO/FDIS 8728:2023(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national
Formatted: English (United Kingdom)
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 documentsdocument should be noted. This document was drafted in accordance
Formatted: English (United Kingdom)
with the editorial rules of the ISO/IEC Directives, Part 2 (see
www.iso.org/directiveswww.iso.org/directives).
Formatted: English (United Kingdom)
Attention is drawnISO draws attention to the possibility that some of the elementsimplementation of
Formatted: English (United Kingdom)
this document may beinvolve the subjectuse of (a) patent(s). ISO takes no position concerning the
Formatted: English (United Kingdom)
evidence, validity or applicability of any claimed patent rights. in respect thereof. As of the date of
Formatted: English (United Kingdom)
publication of this document, ISO had not received notice of (a) patent(s) which may be required to
implement this document. However, implementers are cautioned that this may not represent the latest
Formatted: English (United Kingdom)
information, which may be obtained from the patent database available at www.iso.org/patents. ISO
Formatted: English (United Kingdom)
shall not be held responsible for identifying any or all such patent rights. Details of any patent rights
Formatted: English (United Kingdom)
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).
Formatted: English (United Kingdom)
Formatted: English (United Kingdom)
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.htmlwww.iso.org/iso/foreword.html.
Formatted: English (United Kingdom)
This document was prepared by Technical Committee ISO/TC 8, Ships and marine technology,
Subcommittee SC 6, Navigation and ship operations.
This fourth edition cancels and replaces the third edition (ISO 8728:2014), which has been technically
Formatted: Pattern: Clear
revised.
Formatted: Pattern: Clear
Formatted: Pattern: Clear
The main changes are as follows:
— in Clause 4 of (abbreviated terms) has been added.;
Formatted: Pattern: Clear
— in 6.3, requirements related to bridge alert management have been added.;
Formatted: Pattern: Clear
— in 7.1, a requirement for display equipment has been added.;
Formatted: Pattern: Clear
Formatted: Pattern: Clear
— in 7.12, test method for requirements related to bridge alert management has been added.;
Formatted: Pattern: Clear
— in Annex B, the equivalent requirements in ISO 8728 and IMO Resolution have been deleted and the
Formatted: Pattern: Clear
alerts with a standard alert identifier have been defined.;
Formatted: Pattern: Clear
© ISO 2023 – All rights reserved v

---------------------- Page: 6 ----------------------
ISO/FDIS 8728:2023(E)
— in Annex C, IEC 61162 interfaces overview has been added.;
Formatted: Pattern: Clear
Formatted: Pattern: Clear
— the normative references and bibliography have been updated.
Formatted: Pattern: Clear
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.
vi © ISO 2023 – All rights reserved

---------------------- Page: 7 ----------------------
ISO/FDIS 8728:2023(E)
www.iso.org/members.html.

Formatted: Don't adjust space between Latin and
Asian text, Don't adjust space between Asian text and
numbers
© ISO 2023 – All rights reserved vii

---------------------- Page: 8 ----------------------
ISO/FDIS 8728:2023(E)
Introduction
This document is aligned with IMO Resolution A.424(XI) on performance standards for gyro-compasses.
Formatted: Default Paragraph Font
Any text in this document which is a citation from the IMO Resolution A.424(XI), appears in italics.
Formatted: Default Paragraph Font
Within these citations, any changes to the original wording of the IMO Resolution A.424(XI) are written
Formatted: Default Paragraph Font
in upright font.
Formatted: Default Paragraph Font
In this document, the following verbal forms are used:
Formatted: Default Paragraph Font

Formatted: Default Paragraph Font
— — “shall” indicates a requirement;
Formatted: Body Text, Tab stops: Not at 19.85 pt +
39.7 pt + 59.55 pt + 79.4 pt + 99.25 pt + 119.05 pt +

138.9 pt + 158.75 pt + 178.6 pt + 198.45 pt
— — “should” indicates a recommendation;
Formatted: List Continue 1

Formatted: List Continue 1
— — “may” indicates a permission;
Formatted: List Continue 1

— — “can” indicates a possibility or a capability.
Formatted: List Continue 1

viii © ISO 2023 – All rights reserved

---------------------- Page: 9 ----------------------
FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 8728:2023(E)
Formatted: Font: 11.5 pt

Ships and marine technology — Marine gyro-compasses
1 Scope Formatted: Don't adjust space between Latin and
Asian text, Don't adjust space between Asian text and
This document specifies the construction, performance, and type testing for gyro-compasses which are numbers
required by the International Convention for the Safety of Life at Sea (SOLAS), 1974 (as amended),
Chapter V, Regulation 19.
This document specifies the minimum requirements, the construction, performance, and type testing
for gyro-compasses, which required to comply with the performance standards adopted by the IMO
Formatted
...
Resolution A.424(XI).
2 Normative references
Formatted: Default Paragraph Font
Formatted: Don't adjust space between Latin and
The following documents are referred to in the text in such a way that some or all of their content
Asian text, Don't adjust space between Asian text and
constitutes requirements of this document. For dated references, only the edition cited applies. For
numbers
undated references, the latest edition of the referenced document (including any amendments) applies.
IEC 60945, Maritime navigation and radiocommunication equipment and systems — General
Formatted
...
requirements — Methods of testing and required test results
IEC 61162--1, Marine navigation and radiocommunication equipment and systems — Digital interfaces -
Formatted
...
Part 1: Single talker and multiple listeners
IEC 61162--2, Maritime navigation and radiocommunication equipment and systems — Digital interfaces
Formatted
...
— Part 2: Single talker and multiple listeners, high-speed transmission
IEC 61162--450, Maritime navigation and radiocommunication equipment and systems - Digital
Formatted
...
interfaces - Part 450: Multiple talkers and multiple listeners - Ethernet interconnection
IEC 62288, Maritime navigation and radiocommunication equipment and systems — Presentation of
Formatted
...
navigation-related information on shipborne navigational displays — General requirements, methods of
testing and required test results
IEC 62923--1:2018, Maritime navigation and radiocommunication equipment and systems — Bridge alert
Formatted
...
management — Part 1: Operational and performance requirements, methods of testing and required test
results
IEC 62923--2, Maritime navigation and radiocommunication equipment and systems — Bridge alert
Formatted
...
management — Part 2: Alert and cluster identifiers and other additional features
IMO Resolution MSC.302(87), Performance standards for bridge alert management
Formatted
...
IMO Resolution MSC.191(79), Performance standards for the presentation of navigation-related
Formatted
...
information on shipborne navigational displays
IMO Resolution MSC.466(101), Amendments to the performance standards for the presentation of
Formatted
...
navigation-related information on shipborne navigational displays (Resolution MSC.191(79))
© ISO 2023 – All rights reserved 1

---------------------- Page: 10 ----------------------
ISO/FDIS 8728:2023(E)
3 Terms and definitions
Formatted: Don't adjust space between Latin and
Asian text, Don't adjust space between Asian text and
For the purposes of this document, the following terms and definitions apply. numbers
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
Formatted: Font: Cambria
— ISO Online browsing platform: available at https://www.iso.org/obphttps://www.iso.org/obp
Formatted: Default Paragraph Font, English (United
Kingdom)
— IEC Electropedia: available at https://www.electropedia.org/https://www.electropedia.org/
Formatted: Default Paragraph Font, English (United
Kingdom)
3.1
Formatted: Don't adjust space between Latin and
gyro-compass
Asian text, Don't adjust space between Asian text and
complete equipment comprising all essential elements of the complete design, including both the gyro-
numbers
compass as heading sensor and the associated heading transmission system
[SOURCE: IMO Resolution A.424(XI), 2.1, modified — elements of complete design have been specified.]
Formatted: Default Paragraph Font
Formatted: Default Paragraph Font
3.2
Formatted: Default Paragraph Font
true heading
horizontal angle between the vertical plane passing through the true meridian and the vertical plane
Formatted: Don't adjust space between Latin and
passing through the ship’s fore-and-aft datum line
Asian text, Don't adjust space between Asian text and
numbers, Tab stops: 19.85 pt, Left + 39.7 pt, Left +
Note 1 to entry: The true heading is measured from true north (000°) clockwise through 360°.
59.55 pt, Left + 79.4 pt, Left + 99.25 pt, Left + 119.05
pt, Left + 138.9 pt, Left + 158.75 pt, Left + 178.6 pt,
Note 2 to entry: When the gyro-compass equipment is not installed on board ship, this “true heading” is regarded
Left + 198.45 pt, Left
as the true heading of the lubber line. Where a gyro-compass has the facility of introducing a correction by moving
Formatted: Default Paragraph Font
the lubber line, the correction is
...