ISO 13755:2020

INTERNATIONAL ISO
STANDARD 13755
Second edition
2020-08
Ships and marine technology —
Ship's mooring and towing fittings —
Steel rollers
Navires et technologie maritime — Corps-morts et ferrures de
remorquage de navires — Rouleaux en acier
Reference number
©
ISO 2020
© ISO 2020
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ii © ISO 2020 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Classification . 1
4.1 Type . 1
4.2 Nominal sizes . 1
5 Dimensions . 2
6 Materials . 2
7 Construction . 2
8 Manufacturing and inspection . 2
9 Marking . 2
Annex A (normative) Basis for strength assessment of steel rollers .16
Bibliography .18
Foreword
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electrotechnical standardization.
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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).
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www .iso .org/ iso/ foreword .html.
This document was prepared Technical Committee ISO/TC 8, Ships and marine technology, Subcommittee
SC 4, Outfitting and deck machinery.
This second edition cancels and replaces the first edition (ISO 13755:2012), which has been editorially
and technically revised.
The main changes compared to the previous edition are as follows:
— technical guidelines have been added in 7.3 and 7.4;
— the definition of SWL (3.1) has been reworded;
— the object line, extension line, dimension line and welding volume in Figures 1, 4 and 6 have been
amended;
— the column titles in Table 1 have been amended.
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 2020 – All rights reserved

Introduction
The steel roller is a type of ship’s mooring fitting installed on board, to lead the mooring rope from the
ship’s inboard to outboard as a shipside roller fairlead, and to change the direction of the ropes as a
pedestal fairlead.
INTERNATIONAL STANDARD ISO 13755:2020(E)
Ships and marine technology — Ship's mooring and towing
fittings — Steel rollers
1 Scope
This document specifies the types, nominal sizes, dimensions and materials, as well as construction,
manufacturing and marking requirements, for steel rollers installed to lead the mooring rope of a ship.
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 13767, Ships and marine technology — Ship’s mooring and towing fittings — Shipside roller fairleads
ISO 13776, Ships and marine technology — Ship’s mooring and towing fittings — Pedestal fairleads
IMO Circular MSC/Circ.1175, Guidance on shipboard towing and mooring equipment
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
safe working load
SWL
safe load limit (maximum permissible load) of the fittings used for mooring and towing
4 Classification
4.1 Type
Depending on the construction, steel rollers shall be classified as belonging to one of the following
three types:
a) Type A: made of steel casting without upper dust cover;
b) Type B: made of steel casting with upper dust cover;
c) Type C: made of steel plate with dust cover.
4.2 Nominal sizes
The nominal sizes, D , of steel rollers are denoted by reference to the outside diameter of the roller, in
n
millimetres, from a basic series of preferred numbers.
The nominal sizes are: 150, 200, 250, 300, 350, 400, 450 and 500.
5 Dimensions
The steel rollers shall have dimensions and particulars in accordance with Tables 1, 2, 3, 4, 5, 6, 7 and 8,
and Figures 1, 2, 3, 4, 5, 6, 7 and 8.
6 Materials
The following materials shall be used for manufacturing the different components of steel rollers:
a) roller: steel casting having a yield point of not less than 205 N/mm , or steel plates having a yield
point of not less than 235 N/mm ;
b) axle: weldable steel casting having a yield point of not less than 350 N/mm or equivalent;
c) bush: brass, bronze or equivalent.
7 Construction
7.1 The rollers of the steel rollers (Type C) shall be constructed from steel tubes or formed from plate.
7.2 The foundation of the steel rollers shall be determined by the manufacturer in accordance
with ISO 13767 and ISO 13776. The foundation and welding connections shall guarantee a reliable
transmission of the maximum loading of the steel rollers to the hull construction without any plastic
deformation or cracks.
7.3 The selection of ship’s mooring fittings and mooring lines should take into account the diameter, D,
of surfaces of mooring fittings that are in contact with the mooring line diameter, d, (D/d ratio) to reduce
or mitigate bend loss of strength.
7.4 The tensile strength of a mooring rope may be reduced depending on the bend radius (D/d ratio)
through the mooring fittings, in accordance with the rope manufacturer’s guidelines.
8 Manufacturing and inspection
8.1 All surfaces of the steel rollers, including welded surfaces, shall be free from any visible flaws or
imperfections.
8.2 All surfaces in contact with the ropes shall be free from surface roughness or irregularities likely to
cause damage to the ropes by abrasion.
8.3 The steel rollers shall be coated externally with an anti-corrosion protective finish.
8.4 All rotatin
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