SIST EN ISO 8847:2021
(Main)Small craft - Steering gear - Cable over pulley systems (ISO 8847:2021)
Small craft - Steering gear - Cable over pulley systems (ISO 8847:2021)
This document specifies the requirements for the design, installation and testing of cable over pulley
steering systems on small craft with or without a propulsion engine(s), and on small craft with outboard
engine(s) up to and including 37 kW total power.
It specifies the requirements for the design and testing of all components of a cable over pulley steering
system, from the steering mechanism to the mechanical interface with the rudder shaft or the outboard
engine. It applies to cable over pulley steering systems, whether for pedestal or bulkhead types.
This document does not address emergency means of steering the craft.
Kleine Wasserfahrzeuge - Steuerungssystem - Kabel- und Seilzugsteuerung (ISO 8847:2021)
Dieses Dokument legt die Anforderungen an Entwurf, Einbau und Prüfungen von Seilzug-Steueranlagen auf kleinen Wasserfahrzeugen mit oder ohne Antriebsmotor(en) und auf kleinen Wasserfahrzeugen mit Außenbordmotor(en) bis einschließlich 37 kW Gesamtleistung fest.
Es legt die Anforderungen an Entwurf und Prüfung aller Bauteile einer Seilzug-Steueranlage von der Lenkvorrichtung bis zur mechanischen Verbindung mit dem Ruderschaft oder dem Außenbordmotor fest. Es gilt für Seilzug-Steueranlagen, die sowohl an einer Steuersäule als auch am Schott montiert sein können.
Dieses Dokument behandelt keine Mittel zur Steuerung des Wasserfahrzeugs im Notfall (Notsteuerung).
Petits navires - Appareils à gouverner - Systèmes à drosses et réas (ISO 8847:2021)
Le présent document spécifie les exigences relatives à la conception, à l’installation et aux essais des systèmes de direction à câble sur poulie installés sur les petits navires avec ou sans moteur(s) de propulsion et sur les petits navires avec moteur(s) hors-bord d’une puissance totale inférieure ou égale à 37 kW.
Il spécifie les exigences relatives à la conception et aux essais de tous les composants d’un système de direction à câble sur poulie, depuis le mécanisme de direction jusqu’à l’interface mécanique avec la mèche de gouvernail ou le moteur hors-bord. Il s'applique aux systèmes de direction à câble sur poulie, qu'ils soient de type sur colonne ou sur cloison.
Ce document ne traite pas des dispositifs de barre de secours pour diriger le bateau.
Mala plovila - Krmilni mehanizem - Sistemi s kabli preko škripčevja (ISO 8847:2021)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 8847:2021
01-oktober-2021
Nadomešča:
SIST EN ISO 8847:2017
Mala plovila - Krmilni mehanizem - Sistemi s kabli preko škripčevja (ISO
8847:2021)
Small craft - Steering gear - Cable over pulley systems (ISO 8847:2021)
Kleine Wasserfahrzeuge - Steuerungssystem - Kabel- und Seilzugsteuerung (ISO
8847:2021)
Petits navires - Appareils à gouverner - Systèmes à drosses et réas (ISO 8847:2021)
Ta slovenski standard je istoveten z: EN ISO 8847:2021
ICS:
47.020.70 Navigacijska in krmilna Navigation and control
oprema equipment
47.080 Čolni Small craft
SIST EN ISO 8847:2021 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 8847:2021
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SIST EN ISO 8847:2021
EN ISO 8847
EUROPEAN STANDARD
NORME EUROPÉENNE
July 2021
EUROPÄISCHE NORM
ICS 47.080 Supersedes EN ISO 8847:2017
English Version
Small craft - Steering gear - Cable over pulley systems (ISO
8847:2021)
Petits navires - Appareils à gouverner - Systèmes à Kleine Wasserfahrzeuge - Steuerungssystem - Kabel-
câble sur poulie (ISO 8847:2021) und Seilzugsteuerung (ISO 8847:2021)
This European Standard was approved by CEN on 5 March 2021.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 8847:2021 E
worldwide for CEN national Members.
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SIST EN ISO 8847:2021
EN ISO 8847:2021 (E)
Contents Page
European foreword . 3
Annex ZA (informative) Relationship between this European Standard and the essential
requirements of Directive 2013/53/EU aimed to be covered . 4
2
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SIST EN ISO 8847:2021
EN ISO 8847:2021 (E)
European foreword
This document (EN ISO 8847:2021) has been prepared by Technical Committee ISO/TC 188 "Small
craft" in collaboration with Technical Committee CEN/TC 464 “Small Craft” the secretariat of which is
held by SIS.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by January 2022, and conflicting national standards shall
be withdrawn at the latest by January 2022.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 8847:2017.
This document has been prepared under a Standardization Request given to CEN by the European
Commission and the European Free Trade Association, and supports essential requirements of EU
Directive(s) / Regulation(s).
For the relationship with EU Directive(s) / Regulation(s), see informative Annex ZA, which is an integral
part of this document.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN websites.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 8847:2021 has been approved by CEN as EN ISO 8847:2021 without any modification.
3
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SIST EN ISO 8847:2021
EN ISO 8847:2021 (E)
Annex ZA
(informative)
Relationship between this European Standard and the essential
requirements of Directive 2013/53/EU aimed to be covered
This European Standard has been prepared under a Commission’s standardization request
M/542/C(2015) 8736 final to provide one voluntary means of conforming to essential requirements of
Directive 2013/53/EU.
Once this standard is cited in the Official Journal of the European Union under that Directive,
compliance with the normative clauses of this standard given in Table ZA.1 confers, within the limits of
the scope of this standard, a presumption of conformity with the corresponding essential requirements
of that Directive, and associated EFTA regulations.
Table ZA.1 — Correspondence between this European Standard and
Annex I of Directive 2013/53/EU
Essential Requirements of Clause(s)/sub-clause(s) Remarks/Notes
Directive 2013/53/EU of this EN
Annex I, Clause 5.4.1, Steering 4, 5, 6, 7 and 9 This standard specifies
system, general. requirements for cable over
pulley steering systems only
from the helm to the connection
to the rudder or outboard engine.
This Standard does not address
an emergency means of steering.
This standard does not address
propulsion control systems.
Annex I, Clause 2.5, Owner’s 8 In respect of information for
Manual cable over pulley steering
systems only.
Annex II, Components of 4, 5, 6, 7 and 9 In respect of cable over pulley
watercraft (3) Steering wheels, steering systems and their major
steering mechanisms and cable components only.
assemblies.
Steering wheels supplied as
components are excluded from
this standard.
WARNING 1 — Presumption of conformity stays valid only as long as a reference to this European
Standard is maintained in the list published in the Official Journal of the European Union. Users of this
standard should consult frequently the latest list published in the Official Journal of the European
Union.
WARNING 2 — Other Union legislation may be applicable to the product(s) falling within the scope of
this standard.
4
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SIST EN ISO 8847:2021
INTERNATIONAL ISO
STANDARD 8847
Third edition
2021-06
Small craft — Steering gear — Cable
over pulley systems
Petits navires — Appareils à gouverner — Systèmes à câble sur poulie
Reference number
ISO 8847:2021(E)
©
ISO 2021
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SIST EN ISO 8847:2021
ISO 8847:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
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.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 8847:2021
ISO 8847:2021(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General requirements . 4
5 Steering system requirements . 5
6 Installation . 9
7 Testing requirements .13
8 Owner’s manual.17
9 Instruction manual .17
Annex A (informative) Steering wheel and helm shaft fit .18
Annex B (informative) Recommended procedures for conducting cable over pulley strength
tests as required in 7.2.2 for outboard engine applications — Tangential load test .20
Bibliography .23
© ISO 2021 – All rights reserved iii
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SIST EN ISO 8847:2021
ISO 8847:2021(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 188, Small craft, in collaboration with
the European Committee for Standardization (CEN) Technical Committee CEN/TC 464, Small craft, in
accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
This third edition cancels and replaces the second edition (ISO 8847:2004), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— update of the scope to clarify application on small craft with and without propulsion engine(s);
— addition to the scope of small craft with outboard engines up to and including 37 kW total power;
— update of the definitions;
— update of requirements to meet state of the art;
— addition of informative Annexes A and B.
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.
iv © ISO 2021 – All rights reserved
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SIST EN ISO 8847:2021
INTERNATIONAL STANDARD ISO 8847:2021(E)
Small craft — Steering gear — Cable over pulley systems
1 Scope
This document specifies the requirements for the design, installation and testing of cable over pulley
steering systems on small craft with or without a propulsion engine(s), and on small craft with outboard
engine(s) up to and including 37 kW total power.
It specifies the requirements for the design and testing of all components of a cable over pulley steering
system, from the steering mechanism to the mechanical interface with the rudder shaft or the outboard
engine. It applies to cable over pulley steering systems, whether for pedestal or bulkhead types.
This document does not address emergency means of steering the craft.
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 2408:2017, Steel wire ropes — Requirements
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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
accessible
capable of being reached for operation, inspection or maintenance without removal of permanent
structure of the craft
3.2
cable
flexible mechanical means of transmitting tension forces from one location to another
Note 1 to entry: This cable can be metallic or non-metallic.
3.3
cable drum
circular feature of the steering mechanism (3.10) over which the steering cable (3.2) is routed to provide
the required cable travel
3.4
cable over pulley steering system
steering system in which rotation of the steering wheel transmits movement to either the steering arm
quadrant fastened to the rudder shaft, or to the outboard engine steering arm, by mechanical means
including flexible cable over pulleys mounted to the structure of the craft
© ISO 2021 – All rights reserved 1
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SIST EN ISO 8847:2021
ISO 8847:2021(E)
3.5
cable load
force applied to the cable (3.2) providing the necessary torque to move either the rudder through the
rudder shaft/steering arm or the outboard engine while the craft is underway
3.6
cable-in conduit-steering system
steering system in which rotation of the steering wheel transmits movement to either the steering arm
quadrant fastened to the rudder shaft, or to the outboard engine steering arm, by mechanical means
including flexible cable (3.2) and conduits with or without use of pulleys
3.7
fairlead
ring, eye or loop that guides a cable (3.2) in the desired direction
Note 1 to entry: A pulley can also perform the function of a fairlead.
3.8
swivel pulley
pulley whose attachment feature is designed to allow the pulley to rotate freely about the swivel
centreline
Note 1 to entry: See Figure 1, left side.
3.9
fixed strap pulley
pulley whose attachment is designed for minimum, if any, rotation of the pulley assembly about the
fixed strap axis
Note 1 to entry: See Figure 1, right side.
Dimensions in millimetres
2 © ISO 2021 – All rights reserved
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SIST EN ISO 8847:2021
ISO 8847:2021(E)
Key
1 swivel
2 cheek strap
3 fixed strap
4 sheave
5 pulley pin
Figure 1 — Swivel and fixed strap pulleys cable over pulley systems
3.10
steering mechanism
device to which a control element (3.20) is attached for manual application of a controlling force, and by
which the controlling force is fed into a steering system (3.14)
3.11
helm station
location from which steering, propulsion and thrust can be controlled
3.12
minimum retained system performance
system capability after test(s) such that at least 90 % of the outboard engine steering arm travel
normally available each side of the mid-position can be attained by exertion of no more than 27 Nm of
torque at the helm through the steering mechanism (3.10), through the control element (3.20)
Note 1 to entry: These limits are not intended to define a condition under which a craft can or cannot be safely
operated but are intended to provide quantitative limits for design and testing purposes.
3.13
steering arm
component fixed to the rudder shaft with at least one groove for the cable (3.2) concentric to the shaft
centre or for outboard engines, the portion of the outboard engine that the steering system makes
mechanical interface (3.21) with
Note 1 to entry: The steering arm can be a wheel quadrant (see Figure 2a), a quadrant (see Figure 2b) or a tiller
quadrant (see Figure 2c).
a) Wheel quadrant b) Quadrant c) Tiller quadrant
Figure 2 — Examples of steering arm types
3.14
steering system
assembly including all components necessary to transmit remote manual effort to the rudder blade
steering arm quadrant or to the outboard engine steering arm
© ISO 2021 – All rights reserved 3
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SIST EN ISO 8847:2021
ISO 8847:2021(E)
3.15
total steering loss
complete loss of the ability to steer the craft from the helm station (3.11) by application of manual effort
to the control element (3.20)
3.16
steering wheel
mechanical means for applying manual steering effort to the helm, normally a circular configuration
with a continuous loop at the distal end of support spokes with the steering mechanism (3.10) connected
at the rotational axis
3.17
steering wheel diameter
actual diameter
D
a
diameter of the circle formed by the outermost sections of the steering wheel (3.16)
Note 1 to entry: See Figure 3.
3.18
steering wheel dish
distance between the two parallel planes formed by the aft rim surface and the forward hub surface of
a steering wheel (3.16)
Note 1 to entry: see Figure 3.
3.19
craft
small craft
recreational boat, and other watercraft using similar equipment, of up to 24 m length of hull (L )
H
Note 1 to entry: The measurement methodology for the length of hull is defined in ISO 8666.
[SOURCE: ISO 8666:2020, 3.15, modified – Note 1 to entry has been added.]
3.20
control element
device connected to the steering mechanism (3.10) that allows the operator to apply manual steering
effort to the steering system (3.14)
3.21
mechanical interface
interface where force and motion are transmitted mechanically
3.22
sailing boat
craft (3.19) for which the primary means of propulsion is by wind power, having reference sail area
2/3
(A ) ≥ 0,07 (m )
S LDC
[SOURCE: ISO 8666:2020, 3.11]
4 General requirements
4.1 Components of the steering system shall be fastened securely to the structure of the craft,
reinforced where necessary, especially at the steering mechanism bulkhead/pedestal mounting and at
pulleys.
4.2 On a sailing boat, the steering arm connection to the rudder shaft shall be capable of transmitting
the required steering torque to the rudder.
4 © ISO 2021 – All rights reserved
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SIST EN ISO 8847:2021
ISO 8847:2021(E)
NOTE Rudder requirements are addressed in ISO 12215-8.
4.3 Cable over pulley steering systems designed to meet the requirements of this document shall not
be used to steer craft having outboard engine(s) in excess of 37 kW total power.
4.4 All threaded fasteners whose integrity affects safe operation of the steering system so that
separation or loss of the fasteners can cause total steering loss without warning shall be provided with a
locking means.
4.4.1 Threaded fasteners that can be expected to be disturbed by installation or adjustment procedures
s
...
SLOVENSKI STANDARD
oSIST prEN ISO 8847:2020
01-februar-2020
Mala plovila - Krmilni mehanizem - Sistemi s kabli preko škripčevja (ISO/DIS
8847:2019)
Small craft - Steering gear - Cable over pulley systems (ISO/DIS 8847:2019)
Kleine Wasserfahrzeuge - Steuerungssystem - Kabel- und Seilzugsteuerung (ISO/DIS
8847:2019)
Petits navires - Appareils à gouverner - Systèmes à drosses et réas (ISO/DIS
8847:2019)
Ta slovenski standard je istoveten z: prEN ISO 8847
ICS:
47.020.70 Navigacijska in krmilna Navigation and control
oprema equipment
47.080 Čolni Small craft
oSIST prEN ISO 8847:2020 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
oSIST prEN ISO 8847:2020
---------------------- Page: 2 ----------------------
oSIST prEN ISO 8847:2020
DRAFT INTERNATIONAL STANDARD
ISO/DIS 8847
ISO/TC 188 Secretariat: SIS
Voting begins on: Voting terminates on:
2019-12-06 2020-02-28
Small craft — Steering gear — Cable over pulley systems
Petits navires — Appareils à gouverner — Systèmes à drosses et réas
ICS: 47.080
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 8847:2019(E)
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 SUPPORTING DOCUMENTATION. ISO 2019
---------------------- Page: 3 ----------------------
oSIST prEN ISO 8847:2020
ISO/DIS 8847:2019(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
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.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved
---------------------- Page: 4 ----------------------
oSIST prEN ISO 8847:2020
ISO/DIS 8847:2019(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General Requirements . 4
5 Construction requirements . 4
6 Installation . 8
7 Testing Requirements .14
8 Owner’s manual.17
9 Instruction manual .17
Annex A (informative) Recommended procedures for conducting cable over pulley strength
tests required in Section 7.1 for outboard engine applications .19
Annex ZA (informative) Relationship between this European Standard and the essential
requirements of Directive 2013/53/EU aimed to be covered .22
© ISO 2019 – All rights reserved iii
---------------------- Page: 5 ----------------------
oSIST prEN ISO 8847:2020
ISO/DIS 8847:2019(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 on 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 the following
URL: www .iso .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 188 Small craft.
This fourth edition cancels and replaces the third edition (ISO 8847:2017), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— Update of the definitions;
— Update of requirements to meet current industry practice;
— Addition of powered craft with outboard engines up to and including 37 kW total horsepower.
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
iv © ISO 2019 – All rights reserved
---------------------- Page: 6 ----------------------
oSIST prEN ISO 8847:2020
DRAFT INTERNATIONAL STANDARD ISO/DIS 8847:2019(E)
Small craft — Steering gear — Cable over pulley systems
1 Scope
This document specifies the requirements for the design, construction, installation and testing of cable
over pulley steering systems on sailing craft of hull lengths up to 24 m with or without an auxiliary
engine and powered craft of hull lengths up to 24 m with outboard engines up to and including 37 kW
total horsepower.
This document specifies the requirements for the design and construction of all components of a
steering system from the helm to rudder connection point or connection to the outboard engine. It
applies to cable over pulley steering systems, whether for pedestal or bulkhead types.
This document does not address emergency means of steering the craft.
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 2408:2017, Steel wire ropes — Requirements
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at https:// www .iso .org/ obp
3.1
accessible
capable of being reached for operation, inspection or maintenance without removal of permanent
structure of the craft
3.2
cable
flexible mechanical means of transmitting tension forces from one location to another
Note 1 to entry: This cable could be metallic or non-metallic
3.3
cable drum
circular feature of the steering helm over which the steering cable is routed to provide the required
cable travel
3.4
cable over pulley steering system
asteering system in which rotation of the steering wheel transmits movement of the rudder blade
steering arm quadrant fastened to the rudder shaft or outboard steering arm by mechanical means
including flexible cable over pulleys mounted to the structure of the craft
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3.5
cable load
Force applied to the cable providing the necessary torque to move the rudder through the rudder shaft/
steering arm or outboard engine while the craft is underway
3.6
cable in conduit steering systems
steering system in which rotation of the steering wheel transmits movement of the rudder blade
steering arm quadrant fastened to the rudder shaft or outboard steering arm by mechanical means
including flexible cable and conduits with or without use of pulleys
3.7
fairlead
ring, eye or loop that guides a cable in the desired direction. A pulley may also perform the function of
a fairlead
3.8
swivel pulley
pulley whose attachment feature is designed to allow the pulley to rotate freely about the swivel
centreline. See Figure 1
3.9
fixed strap pulley
pulley whose attachment is designed for minimum if any rotation of the pulley assembly about the fixed
strap axis. See Figure 1
Key
1 swivel
2 cheek strap
3 fixed strap
4 sheave
Figure 1 — Pulleys for outboard cable over pulley systems
3.10
steering helm
operator input device for the control of steering
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3.11
helm station
location from which steering, propulsion and thrust can be controlled
3.12
minimum retained system performance
System capability after test(s) such that at least 90% of the rudder blade steering arm quadrant or
outboard engine steering arm travel normally available each side of the mid-position may be attained
by exertion of no more than 27 Nm of torque at the helm through the steering wheel.
Note 1 to entry: These limits are not intended to define a condition under which a craft can or cannot be safely
operated but are intended to provide quantitative limits for design and testing purposes.
3.13
steering armcomponent fixed to the rudder shaft with at least one groove for the cable concentric
to the shaft centre.
Note 1 to entry: The steering arm may be a wheel quadrant (see Figure 2a), a quadrant (see Figure 2b) or a tiller
quadrant (see Figure 2c).
a) wheel quadrant b) quadrant c) tiller quadrant
Figure 2 — Examples of steering arm types
3.14
steering system
assembly including all components necessary to transmit remote manual effort to the rudder blade
steering arm quadrant or outboard engine steering arm
3.15
total steering loss
complete loss of the ability to steer the craft from the helm position by application of manual effort to
the steering wheel
3.16
steering wheel
mechanical means for applying manual steering effort to the helm, normally a circular configuration
with a continuous loop at the distal end of support spokes with the helm connected at the rotational axis
3.17
steering wheel diameter
the diameter of the circle formed by the outermost sections of the steering wheel, See Figure 3
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3.18
steering wheel dish
the distance between the two parallel planes formed by the aft rim surface and the forward hub surface
of a steering wheel, see Figure 3
3.19
craft
small craft
recreational craft, and other watercraft using similar equipment, of up to 24 m length of hull (L )
H
4 General Requirements
4.1 To ensure the proper operation of a steering system, all components shall be fastened securely to
the structure of the craft, reinforced where necessary, especially at the helm bulkhead/pedestal mounting
and at pulleys.
4.2 The steering arm connection to the rudder shaft shall also be capable of transmitting the required
steering torque to the rudder.
4.3 Cable over pulley steering systems designed to meet the requirements of this standard shall not be
used to steer craft having engine(s) in excess of 37 kW total power.
4.4 All threaded fasteners whose integrity affects safe operation of the steering system such that
separation or loss of the fasteners may cause sudden loss of steering without warning shall be provided
with a locking means.
4.4.1 Threaded fasteners that may be expected to be disturbed by installation or adjustment
procedures, shall be referenced by instructions for correct assembly and –
4.4.2 Shall be locked by a device whose presence is determined by visual inspection or by feel following
assembly, or
4.4.3 Shall incorporate an integral locking means, provided the fastener cannot be omitted or
substituted without making the steering system inoperable.
NOTE Self-locking nuts with plastic inserts that create mechanical plastic interference meet the above
stated requirements.
4.4.4 Loose lock washers, distorted thread nuts or separately applied adhesives are prohibited.
4.4.5 Plain threaded jam nuts may be used to permit adjustments and shall be designed so that total
separation of parts or other complete loss of steering will not occur should they loosen.
5 Construction requirements
5.1 Steering stops for the outboard engine shall permit at least 30° of angular movement either side of
centre. Stops for the rudder blade steering arm quadrant shall be set by the hull design engineer.
5.2 When used with an outboard engine, the cable over pulley steering system attachment to the
engine shall be designed so that with any combination of engine turn and tilt, there will be no damaging
interference between the engine, its accessories, the steering system and the craft.
5.3 Installation instructions for the steering helm shall include recommendations for the maximum
diameter and deepest dish wheel that can be used with the helm. In addition, the maximum diameter and
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deepest dish wheel information shall be permanently marked so as to be visible with the helm installed
and the wheel removed. See Figure 3
Key
1 dish
2 diameter
3 actual diameter
4 wheel level line
Figure 3 — Steering wheel terms
5.3.1 When equipped with the largest diameter and deepest dish steering wheel for which the helm is
rated, all steering components shall be of sufficient strength to successfully pass the Testing Requirements
of Section 7.
5.4 The radius of the steering arm and cable diameter shall be chosen such that the cable load is less
than 25 % of the cable breaking strength. The steering arm radius shall be concentric with the rudder
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shaft centre. The radius at the end of the groove where the cable is led out shall be at least 5 times the
diameter of the cable used. See Figure 4.
Key
1 end grove
2 Rad a, ≥ 5 x cable diameter
3 steering arm radius
Figure 4 — Steering arm nomenclature
5.5 Cable drums shall provide for 760 mm of cable travel minimum.
5.6 Plastics and elastomers shall be designed to resist degradation from ultraviolet radiation, salt
water, hydrocarbons and ozone.
5.7 All steering components shall be sized to prevent derailing or jamming of the cable.
5.8 Components of the steering system shall be resistant to corrosion, either by virtue of material or
coating thereof, and shall be galvanically compatible with adjoining components.
5.9 Cables
5.9.1 Cables shall be of flexible construction.
5.9.2 Wire rope characteri
...
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