ISO 4853:2023

ISO/DISFDIS 4853:2022(E)
2022-05-24
ISO/TC 8/SC 4/WG 2
Secretariat: SAC
Date: 2023-02-01
Ships and marine technology — A-frame launch and recovery
system
FDIS stage
© ISO 2023 – All rights reserved

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ISO #####-#:####(X/FDIS 4853:2023(E)
© 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.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
E-mail: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO #### 2023 – All rights reserved

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© ISO 2022 – All rights reserved ISO/FDIS 4853:2023(E)
Contents
Foreword . iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Operation and functional requirements . 2
4.1 Operating position . 2
4.2 Constant tension setting . 2
4.3 Load measuring device . 2
4.4 Emergency release . 2
4.5 Wire rope design . 3
4.6 Cylinder protection . 3
4.7 Loose gear . 3
5 Design . 3
5.1 General . 3
5.2 Conditions without wind . 4
5.3 Conditions with wind . 4
5.4 Allowable stress for A-frame structure member . 5
5.5 Fatigue . 5
5.6 Fracture toughness requirements for critical and main load bearing members . 5
5.6.1 General requirement. 5
2
5.6.2 Steels up to and including 41 kg/mm yield strength . 5
2
5.6.3 Extra high strength steels above 41 kg/mm yield strength. 5
5.6.4 Alternative requirements . 6
6 Acceptance tests and inspection . 6
6.1 General . 6
6.2 Heavy hoisting test and inspection . 6
6.3 Factory acceptance test and inspection . 6
7 Installation testing and inspection . 7
7.1 General . 7
7.2 Test loads . 7
7.3 Examination after testing . 7
Annex A (informative) Hoisting factor . 8
Bibliography . 9

© ISO 2023 – All rights reserved iii

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ISO #####-#:####(X/FDIS 4853:2023(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 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 ISO/SC 4, Outfitting and deck machinery.
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.
Field Code Changed
iv © ISO #### 2023 – All rights reserved

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ISO/DISFDIS 4853:20222023(E)
Ships and marine technology — A-frame launch and recovery
system
1 Scope
This document specifies the design, operation, performance and acceptance test of A-frame launch and
recovery systems (hereinafter referred to as “A-frame LARS”) for underwater applications excluding
lifesaving appliances.
This document is applicable to the design, manufacturing, testing and acceptance of A-frame LARS for
underwater applications excluding lifesaving appliances.
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 3828, Shipbuilding and marine structures — Deck machinery — Vocabulary and symbols
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 3828 and the following 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
— — IEC Electropedia: available at https://www.electropedia.org/
3.1
A-frame launch and recovery system
A-frame LARS
system installed at the stern of ship deck or side-launched, which mainly consists of the structural
members, and associated winches (3.3(3.3)) and loose gear, used to achieve the hoisting, towing and
recovery of the equipment
3.2
A-frame
mechanism that mainly consists of the main structure, oil cylinder, transverse travel trolley (if any),
retractable rack (used for anti-swinging, if any) and pulley block and associated winch used to hoist,
traverse, lower and recovery of the equipment in a coordinated way
Note 1 to entry: The rope can be centered through traverse of transverse travel trolley (if any); the sway of the
hoisted can be reduced by buffering of the retractable rack (if any) and cylinder.
3.3
associated winch
winch used to fulfill the function of hoisting and launch of subsea equipment as well as towing of subsea
equipment in the sea together with the A-frame (3.2(3.2),), by hauling in and paying out steel wire ropes
Note 1 to entry: The associated winch may also act as a functional winch such as a cable winch, to fulfill the function
of launching and recovery of operating equipment such as subsea equipment in combination with the A-frame.
3.4
safe working load
SWL
maximum static load the properly installed lifting appliance is certified to be capable of sustaining under
the design operating condition
© ISO #### 2023 – All rights reserved 1

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ISO/DISFDIS 4853:2022(22023(E)
3.5
operating condition
condition under which the safe working load (3.4(3.4)) of an A-frame launch and recoveryandrecovery
system (3.1(3.1)) is ascertained
Note 1 to entry: The vibration and shock that can be withstood by the equipment during the normal operation of
the ship are ascertained according to the maximum angles of heel, trim, roll and pitch of the ship required by the
user.
3.6
duty factor
factor that makes allowances for the frequency and state of loading for which an A-frame launch and
recoveryandrecovery system (3.1(3.1)) considers in design
3.7
design stress
maximum stress permitted to which any component part of an A-frame (3.2(3.2)) and towing winch may
be subjected under safe working load (3.4(3.4))
Note 1 to entry: When the equipment is subjected to the factor load, both the specified lateral and wind loads are
taken into account.
3.8
minimum hoisting speed
minimum load hoisting speed at which the load does not collide with the hull after the load is lifted away
from the ship
Note 1 to entry: The minimum load hoisting speeds to avoid re-contact for various sea conditions are given in
Formula A.3Formula A.3.
4 Operation and functional requirements
4.1 Operating position
4.1.1 The main control panel is mounted on the position from which the working status of the
equipment is visible. Except for the main control panel, there shall be a portable control box, by which
short distance operation may be available beside the A-frame LARS.
4.1.2 The main control panel and portable control box shall be provided with emergency recovery and
quick release buttons.
4.1.3 Other control functions shall be determined by the buyer and seller.
4.2 Constant tension setting
Under towing conditions, the winch of the A-frame LARS shall have the function of wire rope constant
tension to prevent blockage from damaging equipment during towing. For example, when the wire rope
is blocked at the other end of the seafloor, the instantaneous tension on the wire rope is greater than the
constant tension of the winch, and the winch will draw the rope to prevent damage to winch structure.
4.3 Load measuring device
The A-frame LARS should be fitted with a load measuring device, which can measure the load of wire
rope and record the maximum tension at any time; the. The system shall also be fitted with an overload
alarm indicator which makes indication on the control panel of the cab.
4.4 Emergency release
The A-frame LARS shall be designed to have the capacity of emergency release. The emergency release
load shall be not more than 80 % of the breaking load of the rope. The system shall be capable of normal
operation right after emergency release, while the prime mover of the system shall not operate again
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ISO/DISFDIS 4853:20222023(E)
automatically after emergency release. The emergency release control shall require at least two separate
actions to minimise the risk of inadvertent or incorrect operation.
4.5 Wire rope design
The wire rope shall be anti-corrosion and anti-rotating, and the nominal tensile stre
...

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 4853
ISO/TC 8/SC 4
Ships and marine technology —
Secretariat: SAC
A-frame launch and recovery system
Voting begins on:
2023-02-15
Voting terminates on:
2023-04-12
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 4853:2023(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 4853:2023(E)
FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 4853
ISO/TC 8/SC 4
Ships and marine technology —
Secretariat: SAC
A-frame launch and recovery system
Voting begins on:
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: +41 22 749 01 11
IN ADDITION TO THEIR EVALUATION AS
Reference number
Email: copyright@iso.org
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
ISO/FDIS 4853:2023(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 4853:2023(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Operation and functional requirements . 2
4.1 Operating position . 2
4.2 Constant tension setting . 2
4.3 Load measuring device . 3
4.4 Emergency release . 3
4.5 Wire rope design . 3
4.6 Cylinder protection. 3
4.7 Loose gear . 3
5 Design . 4
5.1 General . 4
5.2 Conditions without wind . 4
5.3 Conditions with wind . 5
5.4 Allowable stress for A­frame structure member . 5
5.5 Fatigue . 6
5.6 Fracture toughness requirements for critical and main load bearing members . 6
5.6.1 General requirement . . 6
2
5.6.2 Steels up to and including 41 kg/mm yield strength . 6
2
5.6.3 Extra high strength steels above 41 kg/mm yield strength . 6
5.6.4 Alternative requirements . 6
6 Acceptance tests and inspection . 7
6.1 General . 7
6.2 Heavy hoisting test and inspection . 7
6.3 Factory acceptance test and inspection . 7
7 Installation testing and inspection . 8
7.1 General . 8
7.2 Test loads . 8
7.3 Examination after testing . 8
Annex A (informative) Hoisting factor . 9
Bibliography .10
iii
© ISO 2023 – All rights reserved

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ISO/FDIS 4853:2023(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 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 ISO/SC 4, Outfitting and deck machinery.
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 2023 – All rights reserved

---------------------- Page: 4 ----------------------
FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 4853:2023(E)
Ships and marine technology — A-frame launch and
recovery system
1 Scope
This document specifies the design, operation, performance and acceptance test of A-frame launch and
recovery systems (hereinafter referred to as “A-frame LARS”) for underwater applications excluding
lifesaving appliances.
This document is applicable to the design, manufacturing, testing and acceptance of A­frame LARS for
underwater applications excluding lifesaving appliances.
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 3828, Shipbuilding and marine structures — Deck machinery — Vocabulary and symbols
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 3828 and the following 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
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
A-frame launch and recovery system
A-frame LARS
system installed at the stern of ship deck or side-launched, which mainly consists of the structural
members, and associated winches (3.3) and loose gear, used to achieve the hoisting, towing and recovery
of the equipment
3.2
A-frame
mechanism that mainly consists of the main structure, oil cylinder, transverse travel trolley (if any),
retractable rack (used for anti-swinging, if any) and pulley block and associated winch used to hoist,
traverse, lower and recovery of the equipment in a coordinated way
Note 1 to entry: The rope can be centered through traverse of transverse travel trolley (if any); the sway of the
hoisted can be reduced by buffering of the retractable rack (if any) and cylinder.
3.3
associated winch
winch used to fulfill the function of hoisting and launch of subsea equipment as well as towing of subsea
equipment in the sea together with the A-frame (3.2), by hauling in and paying out steel wire ropes
Note 1 to entry: The associated winch may also act as a functional winch such as a cable winch, to fulfill the
function of launching and recovery of operating equipment such as subsea equipment in combination with the
A­frame.
1
© ISO 2023 – All rights reserved

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ISO/FDIS 4853:2023(E)
3.4
safe working load
SWL
maximum static load the properly installed lifting appliance is capable of sustaining under the design
operating condition
3.5
operating condition
condition under which the safe working load (3.4) of an A-frame launch and recovery system (3.1) is
ascertained
Note 1 to entry: The vibration and shock that can be withstood by the equipment during the normal operation of
the ship are ascertained according to the maximum angles of heel, trim, roll and pitch of the ship required by the
user.
3.6
duty factor
factor that makes allowances for the frequency and state of loading for which an A-frame launch and
recovery system (3.1) considers in design
3.7
design stress
maximum stress permitted to which any component part of an A-frame (3.2) and towing winch may be
subjected under safe working load (3.4)
Note 1 to entry: When the equipment is subjected to the factor load, both the specified lateral and wind loads are
taken into account.
3.8
minimum hoisting speed
minimum load hoisting speed at which the load does not collide with the hull after the load is lifted
away from the ship
Note 1 to entry: The minimum load hoisting speeds to avoid re-contact for various sea conditions are given in
Formula A.3.
4 Operation and functional requirements
4.1 Operating position
4.1.1 The main control panel is mounted on the position from which the working status of the
equipment is visible. Except for the main control panel, there shall be a portable control box, by which
short distance operation may be available beside the A-frame LARS.
4.1.2 The main control panel and portable control box shall be
...