CDIT Library No.2

Guidelines for the MaintenanceofRubber Fender Systems(2nd Edition)

September 2019

Coastal Development Institute of Technology

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Preface
Port facilities must contribute to society by serving as a base for maritime transportthat supports physical distribution. The Ordinance of MLIT for the Technical Standards
for Port and Harbour Facilities amended in April 2007 requires the maintenance of thePort Facilities subject to the Technical Standards. Based on this Ordinance, the Manualfor Maintenance Techniques of Port and Harbour Facilities compiling the basic concept
for maintenance of port and harbour facilities was published by the Coastal
Development Institute of Technology in October 2007.
The fender system plays a key role in the safe berthing of a vessel and in stableloading/unloading as auxiliary equipment at the mooring facility. When the fendersystem is damaged or degraded, considerable economic losses can occur due tosuspension or restriction of the mooring facility, which may affect the operation andmaintenance of the entire port and facility. Accordingly, it is necessary to detect damage
and deterioration of the fender system in the early stages and to implement theappropriate measures according to a correct assessment of the functions of the fendersystem. Thus, the existing technical knowledge concerning the maintenance of fendersystems was compiled and published as the Guidelines for the Maintenance of Rubber
Fender Systems in July 2010. This book provides specific and easy-to-understanddescriptions of the checks and diagnostic methods and the replacement methods offender systems.
Since then, revisions have been requested, including knowledge and discoveries madefrom the investigation of the 2011 earthquake off the Pacific coast of Tohoku, which led
us to create the second edition of these guidelines in March 2013.
It is my great pleasure to publish the English edition of this guideline, and I hope itwill be widely disseminated to those involved in the maintenance of ports around theworld and used for the maintenance of fenders.

Shigeo Takahashi, President
Coastal Development of Technology
September 2019－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－

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Editorial Committee（Second Edition, 2013）
Committee Chairman:

Shigeru Ueda, Professor Emeritus, Tottori University

Committee member:
Hiroshi Yokota:

Professor, Hokkaido University

Mitsuyasu Iwanami:

Professor, Tokyo Institute of Technology

Toshihiro Kato:

Director of Port Maintenance Planning Office, Ports and Harbour Bureau,
Ministry of Land, Infrastructure, Transport and Tourism

Haruo Yoneyama:

Director, Coastal and Ocean Engineering Department, Port and Airport ResearchInstitute

Shuji Yamamoto:Executive Director, Coastal Development Institute of Technology

Working Group Member:
Toru Okada:
General Manager, Marine & Civil Products, Engineering Division, Meiji
Rubber & Chemical Co.,Ltd
Hiroaki Kouda:
Koko Suzuki:

Manager, Production Engineering Section, Shibata Industrial Co.,Ltd
Industrial Products Engineering Dept., The Yokohama Rubber Co., Ltd.

Masanori Nakagaki： Counselor, Engineering Department, Seibu Polymer Corporation.
Kouhei Morita:

Civil Work & Marine Business Unit, Hybrid Rubber Products HQS., Sumitomo
Rubber Industries, Ltd.

Motohiro Yasui:
Secretariat Office:Yoji Kikuchi:
Kazuhiro Goda:Manager, Marine Fender Department, Bridgestone Corporation

Senior Chief Researcher, Coastal Development Institute of Technology
Researcher, Coastal Development Institute of Technology－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－

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Editorial Committee（First Edition, 2010）
Committee Chairman:

Shigeru Ueda, Professor Emeritus, Tottori University

Committee member:
Hiroshi Yokota:

Professor, Hokkaido University

Jun Sasaki:

Director of Port Maintenance Planning Office, Ports and Harbour Bureau,
Ministry of Land, Infrastructure, Transport and Tourism

Mitsuyasu Iwanami: Team leader, Structural Engineering Research, Port and Airport ResearchInstitute, National Institute of Maritime, Port and Aviation Technology,
National Research and Development Agency
Shuji Yamamoto:
Working Group Member:
Toru Okada:

Executive Director, Coastal Development Institute of Technology

General Manager, Marine & Civil Products, Engineering Division, Meiji
Rubber & Chemical Co.,Ltd

Hiroaki Kouda:
Subleader, Marine Engineering Section, Shibata Industrial Co.,Ltd
Shigeki Sakakibara: Senior Engineer, Industrial Products Engineering Dept., The Yokohama
Rubber Co., Ltd.
Masanori Nakagaki： Counselor, Engineering Department, Seibu Polymer Corporation.
Masahiro Nakamura: Manager, Marine Fender Department, Bridgestone Corporation
Yoshiriro Sugimura: (Former) Manager, Building Material Sales Section, Bridgestone Corporation
Hiroshi Noiri:

Manager, Civil Work & Marine, Infrastructure Products Business Unit, Sumitomo
Rubber Industries, Ltd.

Secretariat Office:Yoji Kikuchi:

Senior Chief Researcher, Coastal Development Institute of Technology

Teruhisa Kawasaki:

Chief Researcher, Coastal Development Institute of Technology

Daijiro Nagasawa:(former) Chief Researcher, Coastal Development Institute of Technology－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－

Guidelines for the Maintenance of Rubber Fender Systems (2nd Edition)
CONTENTS
1. Introduction------------------------------------------------------------------------------------1.1 General----------------------------------------------------------------------------------1.1.1 Summery-----------------------------------------------------------------------1.1.2 Scope---------------------------------------------------------------------------1.1.3 Definition of term-------------------------------------------------------------1.2 Classification of rubber fenders------------------------------------------------------1.2.1 General-------------------------------------------------------------------------1.2.2 Name of each part-------------------------------------------------------------1.3 Method of maintenance management for rubber fenders-------------------------1.3.1 General-------------------------------------------------------------------------1.4 Checks-----------------------------------------------------------------------------------1.4.1 General-------------------------------------------------------------------------1.4.2 Initial check--------------------------------------------------------------------1.4.3 Daily check--------------------------------------------------------------------1.4.4 Periodic check--------------------------------------------------------------------1.4.5 Occasional check--------------------------------------------------------------1.5 Functional evaluation and measures-------------------------------------------------1.5.1 General-------------------------------------------------------------------------1.5.2 Functional evaluation---------------------------------------------------------1.5.3 Countermeasures--------------------------------------------------------------1.5.4 Life-cycle cost-----------------------------------------------------------------1.6 Recording and saving data------------------------------------------------------------[References]---------------------------------------------------------------------------------------

1
1
1
1
2
3
3
6
6
6
8
8
10
10
10
10
11
11
11
11
11
11
11

2. Deterioration factor and deterioration mode of rubber fenders-----------------------------2.1 Summary------------------------------------------------------------------------------2.1.1 General-------------------------------------------------------------------------2.1.2 Deterioration factors of rubber fenders------------------------------------2.1.3 Deterioration modes of rubber fenders------------------------------------2.1.4 Deterioration modes of other rubber equipment--------------------------2.2 V-type rubber fender------------------------------------------------------------------2.2.1 Configuration of V-type rubber fender-------------------------------------2.2.2 Deterioration modes of V-type rubber fender-----------------------------2.3 Rubber fender with fender panel----------------------------------------------------2.3.1 Configuration of rubber fender with panel--------------------------------2.3.2 Deterioration modes of rubber fender with panel------------------------2.4 Pneumatic fender----------------------------------------------------------------------2.4.1 Configuration of pneumatic fender----------------------------------------2.4.2 Deterioration modes of pneumatic fender--------------------------------2.5 Cylindrical fender---------------------------------------------------------------------2.5.1 Configuration of cylindrical fender----------------------------------------2.5.2 Deterioration modes of cylindrical fender---------------------------------

12
12
12
12
15
16
17
17
18
26
26
28
36
36
38
44
44
45

2.6 Other rubber equipment--------------------------------------------------------------2.6.1 Configuration of other rubber equipment---------------------------------2.6.2 Deterioration modes of other rubber equipment-------------------------[References]---------------------------------------------------------------------------------------

46
46
48
51

3. Check diagnosis and functional evaluation of rubber fender---------------------------52
3.1 General----------------------------------------------------------------------------------52
3.1.1 Summary----------------------------------------------------------------------52
3.2 V-type rubber fender-------------------------------------------------------------------54
3.2.1 Method of check/diagnosis and functional evaluation for V-type rubber fender54
3.2.2 Damage rate of V-type rubber fender by field survey-------------------55
3.2.3 Functional evaluation--------------------------------------------------------61
3.2.4 Check sheet and record------------------------------------------------------63
3.3 Rubber fender with fender panel-----------------------------------------------------64
3.3.1 Method of check/diagnosis and functional evaluation for rubber fender with panel 64
3.3.2 Damage rate by field survey for fender with panel----------------------64
3.3.3 Functional evaluation of rubber fender with panel----------------------67
3.3.4 Check sheet and record------------------------------------------------------70
3.4 Pneumatic fender-----------------------------------------------------------------------72
3.4.1 Method of check/diagnosis and functional evaluation for pneumatic fender --72
3.4.2 Deterioration level and degree of airtightness maintenance-------------73
3.4.3 Functional evaluation for pneumatic fender------------------------------76
3.4.4 Check sheet and record------------------------------------------------------80
3.5 Cylindrical fender----------------------------------------------------------------------83
3.5.1 Method of check/diagnosis and functional evaluation for cylindrical fender --83
3.5.2 Damage rate of cylindrical fender by field survey-----------------------83
3.5.3 Functional evaluation--------------------------------------------------------85
3.5.4 Check sheet and record------------------------------------------------------87
3.6 Other rubber equipment---------------------------------------------------------------89
3.6.1 Method of check/diagnosis and functional evaluation for other rubber equipment 89
3.6.2 Damage rate of other rubber equipment by field survey----------------89
3.6.3 Functional evaluation--------------------------------------------------------92
3.6.4 Check sheet and record------------------------------------------------------94[References]--------------------------------------------------------------------------------------95
4. Measures---------------------------------------------------------------------------------------4.1 Summary--------------------------------------------------------------------------------4.1.1 General------------------------------------------------------------------------4.2 Measures for rubber fender-----------------------------------------------------------4.2.1 Measures for rubber body---------------------------------------------------4.2.2 Measures for accessories----------------------------------------------------[References]--------------------------------------------------------------------------------------Appendix-A
Appendix-B
Appendix-C
Appendix-D

Fender control chart-------------------------------------------------------------Standard form of fender check and diagnosis--------------------------------Example of determining deterioration score--------------------------------Example of deterioration rank for fixing--------------------------------------

96
96
96
97
97
97
98
A-1
A-2
A-8
A-20

Chapter 1
Introduction

1.1 General
1.1.1 Summery
This guideline arranges the deterioration forms and factors of rubber fenders as ancillary equipment used in mooring
facilities and transportation facilities in ports and shows appropriate checks and diagnosis methods to evaluate theirfunction. These methods are explained and clarified as the guidelines for the maintenance of rubber fenders.
The standards used in these guidelines and their abbreviations are as shown in Table 1.1.1.
Table 1.1.1 Standards and references for rubber fenders
Abbreviation

References

PHAJ technical standards

Ports and Harbours Association of Japan: Technical Standards andCommentaries for Port and Harbour Facilities in Japan

CDIT maintenance manual

Coastal Development Institute of Technology: Maintenance Guidelines
for Maritime Fender Systems

SCOPE planning guidelines

Service Center of Port Engineering: Guidelines for the maintenancemanagement plan of port facilities

PARI technical notes

K. Terauchi, T. Koizumi, S. Yamamoto, K. Hosokawa: The
deterioration, actual state and the function evaluation of the rubber
fender, No. 878, 1997

1.1.2 Scope
These guidelines apply to the maintenance and management of rubber fenders and other rubber materials used asprotective equipment. These guidelines show the standard maintenance methods of rubber fenders so that facilities cansatisfy the required performance over the service period.
(1) Application of these guidelines
Although the basic concept is indicated in the CDIT maintenance manual and the SCOPE planning guidelines,
these guidelines offer a standard of rubber fenders for the purpose of augmenting these standards. It shows themethod of maintenance management in detail.
The matters not described in these guidelines will be in accordance with the CDIT maintenance manual andthe SCOPE planning guidelines.
(2) What these guidelines show
In mooring facilities, rubber fenders are installed as protection equipment to ensure the safe and smooth
berthing and mooring of vessels, protect bridge piers and reduce damage to colliding vessels in harbour
transportation. During the service period of facilities, equipment such as rubber fenders is usually damaged ordeteriorated by various external actions, and this deterioration is usually evident.
To use these facilities as a high-quality social infrastructure for a certain period of time, proper maintenance isessential for facilities that maintain functions and performance that satisfy a required level during the service
period.
Maintenance management in these guidelines refers to a series of systems that detect deterioration of rubber
fenders effectively, evaluate it rationally, and take effective measures. The basis of maintenance shown in theseguidelines is represented by the following four items. Definitions of terms are shown in 1.1.3.

1

Checks and diagnosis: The act of quantitatively assessing the condition of rubber fenders, the state ofdeterioration, etc. mainly using periodic or temporary checks.
Function evaluation: The act of judging the degree of deterioration of rubber fenders based on the checks anddiagnosis results.
Countermeasures: Maintenance, repair, removal, replacement work, etc., which will be carried out on rubber
fenders based on the results of function evaluation, and measures such as restriction and/or suspension ofoperation that will be carried out for the whole facility.
Comprehensive evaluation: These guidelines show the functional evaluation of rubber fenders and measurestaken based on the results. For a comprehensive evaluation of the entire facility, follow the CDIT
maintenance manual and the SCOPE planning guidelines.
(Note)
In mooring facilities, rubber equipment such as rubber ladders, corner protectors, rubber nets and the like are used asother rubber materials in addition to fenders. These items are not classified as rubber fenders in Table 1.2.1, because
they have less function of converting berthing energy into the energy absorption of fenders. Since they are used asincidental equipment, it is necessary to perform the same maintenance management as fenders.

1.1.3 Definition of terms
The terms used in these guidelines are defined as follows.
Rubber fender (Marine rubber fender): A generic term that includes accessories such as a rubber body andfixing anchor, supporting parts, and fender panels.
Maintenance: A generic term for the action of maintaining the required performance and function of rubber
fenders above a standard.
Design service life: A period of time that continues to meet the required performance of a mooring facility or aport transportation facility design.
Service life: The life of equipment, such as rubber fenders, in mooring facilities and in harbour transportation
facilities.
Function of Marine rubber fender: The role that a rubber fender should play according to purpose or demand.
Performance of Marine rubber fender: The performance that a rubber fender holds to satisfy its function.
Performance requirement: Performance required for the entire facility or for rubber fenders.
Durability of Marine rubber fender: The ability to resist the deterioration of the function and performance of arubber fender over time.
Check: The act of inspecting, diagnosing, and quantitatively assessing the condition of rubber fenders, the stateof deterioration, and functional deterioration.
Damage: Deterioration of rubber fenders that occurs suddenly due to accidental action (abnormal berthing orexcessive vessel motion, etc.) or action not considered in design.
Ageing: The function and performance of a rubber fender decreasing over time due to the natural environment2

and fatigue caused by use.
Deterioration: A generic term for defects such as damage to rubber fenders. Deterioration includes naturalenvironmental deterioration, chemical deterioration, fatigue deterioration, and external force deterioration.
Mode of deterioration: Drops, tears, permanent deformations, missing rubbermissing rubber, cracks, chipping,
separation, wear, ozone cracks, burns, damage to bolt holes, fractures that occur in the rubber body anddeterioration on accessories such as looseness, missing, bending, cutting, or corrosion.
Damage rate: The ratio of damage length or damage area to the length or area of fender facing.
Deterioration rank: The degree of deterioration of the rubber body and accessories such as fixing parts andfender panels. The daily checks of the rubber body and the checks and diagnoses of all accessories are judged
in four stages: a, b, c and d.
Deterioration score: The degree of deterioration of the rubber body. The score is judged by a point system of
0-12 in the initial check and diagnosis, periodic check and diagnosis and occasional check and diagnosis.
Deterioration level: The degree of deterioration occurring in the body of a pneumatic fender. The level isjudged in 6 stages, from I to VI, in the initial check and diagnosis, periodic check and diagnosis andoccasional check and diagnosis.
Degree of airtightness maintenance: The degree of airtightness of the air filled in the body of a pneumatic
fender. The degree is judged in 4 stages, from I to IV, in the initial check and diagnosis, periodic check anddiagnosis and occasional check and diagnosis.
Corrective maintenance: Accepting the deterioration of function due to deterioration of rubber fenders to someextent and addressing deterioration with ex post measures by taking one or two large-scale measures during
the service period of the equipment.
Life-cycle cost: The total cost of a series of processes such as planning, design, construction, maintenance,
dismantling and removal of rubber fenders.

1.2 Classification of rubber fenders
1.2.1 General
Rubber fenders can be classified as follows according to the form of absorbing the berthing energy of the vessel.
(1) V-type rubber fender(2) Rubber fender with fender panel(3) Pneumatic fender(4) Cylindrical rubber fender
Rubber fender classification is summarized in “Guidelines for the Design of Fender Systems” 1). Table 1.2.1 shows
images of the shape, size, reaction force, energy absorption and performance curve for each type of rubber fender
generally used.
(1) V-type rubber fender
A V-type rubber fender is in direct contact with the rubber surface of the fender body and absorbs theberthing energy of the vessel by buckling deformation of the rubber body. Therefore, it is necessary to pay
3attention to the deterioration of rubber due to external force.
(2) Rubber fender with fender panel
A rubber fender with the fender panel brings the vessel into contact with a steel fender panel and absorbs theberthing energy of the vessel by means of buckling deformation of the rubber body. Since the vessel does notcome in direct contact with the rubber, the damage and breakage of the rubber body is slight, but care must be
taken for the corrosion and deformation of the steel fender panel.
(3) Pneumatic fender
A pneumatic fender is a fender that absorbs the energy of the berthing vessel by the elasticity of air filled in
the rubber body and is classified as either a floating pneumatic fender or a fixed pneumatic fender with afender panel. The floating air fender is generally protected by a net, so damage and breakage of the rubber
main body is slight, except for the deterioration of the net. The fixed air fender with a fender panel is a fendersimilar to a rubber fender with a fender panel, and attention must be paid to the corrosion and deformation of
the steel.
With any pneumatic fender, care must be taken to maintain pressure resistance and control air pressure.
(4) Cylindrical rubber fender
In a cylindrical rubber fender, because the vessel is in direct contact with the rubber body and absorbs theberthing energy of the vessel by deformation of the rubber, it is necessary to pay particular attention todeterioration by external force.
(Note)
Chapters 2 and 3 of these guidelines show the standard maintenance practices that apply to rubber fenders. In
addition, the standard maintenance method implemented for other peripheral rubber products is also shown.

4

Table 1.2.1 Overview of different types of rubber fenders
Size
(mm)

Reaction
force
(kN)

Energyabsorption(kN･m)

H/L
250/1000↓
1000/2000

150
↓
2290

15
↓
940

H/L
200/1000↓
1300/3500

150
↓
3400

10
↓
1500

H/L
300/600↓
1000/2000

45
↓
646

6
↓
297

D/H
600/300↓
2065/1150

39
↓
1300

4
↓
577

H/L
300/600↓
1800/2000

66
↓
1708

9
↓
1260

H/L
400/500↓
2500/4000

140
↓
6900

10
↓
7000

D/H
500/300↓
3200/2000

60
↓
4660

9
↓
4840

D/H
650/400↓
3350/3000

56
↓
5688

22
↓
6570

Floating
pneumatic
fender

D/Ｌ
500/1000↓
4500/12000

50
↓
10570

4
↓
9080

Pneumatic
fender with
panel

D/H
600/450↓
3200/3200

138
↓
6210

15
↓
4990

Cylindrical rubber
fender

D/L
150/1000↓
2800/5800

80
↓
6600

3
↓
5000

Pneumatic fender

Buckling-type fender with panel contact

Buckling-type fender with direct contact

Shape

Longitudinal
V-type fender

Circular V-type
fenderLongitudinal
shape withpanel

Circular shapewith panel

5

Performance(Rated deflection %)1.2.2 Name of each part
The names of each part of the rubber fender are as follows.
(1) Rubber body
Main rubber body: The main rubber body refers to a portion made of only rubber material. In pneumatic
fenders, it refers to the inner layer, reinforcing layer, and outer layer that hold air pressure.
Fixing flange: The part that attaches the rubber body to the quay or fender panel. An embedded steel plate is
installed in this part.
Embedded steel plate: The steel plate that is installed to maintain the strength of the fixing flange.
(2) Accessories
Fixing parts: Steel parts for attaching the rubber body to a quay or fender panel, consisting of anchors, bolts,
nuts, washers, etc.
Fender panel: A steel fabricated frame installed on the front (vessel side) of rubber fenders. Since the contact
area between the rubber fender and vessel hull becomes large, it can uniformly transmit the reaction force
generated in the rubber fender to the vessel hull without direct contact of rubber and hull, so it can cope withthe berthing of various vessel types. Thus, it is used to reduce damage to the rubber body.
Support parts: The metal parts installed in a fender with a fender panel to hold the weight of the fender panel
and constrain the displacement of the fender panel as much as possible when the vessel is berthing. Includes
U anchors, brackets with eye plates, chains, turnbuckles, hackles, shock-absorbing devices and so on.
Resin pad: A resin plate equipped on the surface where a steel fender panel comes in contact with vessel hull.
Air inlet valve: A valve for air inlet/exhaust equipped on a pneumatic fender.
Mooring parts: Fitting parts for mooring floating-type pneumatic fenders. Includes U anchors, brackets witheye plates, chains, shackles, rubber sleeves, etc.
Net: Accessory installed for the purpose of protecting the rubber body of a floating pneumatic fender. Includes
chains, wire ropes, rubber sleeves, used tyres, etc.

1.3 Method of maintenance management for rubber fenders
1.3.1 General
The rubber fender should have its function properly maintained based on the maintenance plan so that a mooring
facility and port transportation facility will meet the required performance over a service period. In the maintenanceand management of rubber fenders, the conditions under which equipment is placed, such as natural conditions andusage conditions, structural characteristics, material characteristics, etc. are taken into consideration.
After appropriate checks and diagnoses of damage and deterioration to rubber fenders, such as ageing and functional
evaluation based on the results, necessary measures will be appropriately performed.
(1) Necessity of the maintenance management plan
Rubber fenders are typically used while maintaining their required function for a long period of time. For thispurpose, it is essential not only to consider the initial design of the rubber fenders but also to properly maintainthe facilities in operation.
6

Since rubber fenders are used under harsh natural conditions, they need to be maintained and managed in aplanned and appropriate manner because their functions will deteriorate during the service period of the facility
due to material damage, ageing and so on. In accordance with the flow chart in Fig. 1.3.1, it is standard
procedure to predetermine basic plans and methods such as checks and diagnoses, contents, timing, frequency,
procedures, etc. as maintenance management plans at the start of maintenance. Maintenance management plans
will be prepared in accordance with the SCOPE planning guidelines.
(2) Conditions and characteristics of maintenance and management
For maintenance and management of rubber fenders, it is necessary to plan appropriately in consideration of
the characteristics of the members constituting the materials, difficulty of checks, the types and quality of theused materials, the natural conditions surrounding the equipment, usage importance, future plans of facilities,
diagnosis, substitution and countermeasure work.
(3) Necessary measures
Maintenance and management of rubber fenders refers to a series of procedures for accurately graspingdamage and deterioration over time by appropriate checks and diagnoses, comprehensively evaluating the results,
and taking appropriate measures.
As a result of the functional evaluation of rubber fenders, the necessary measures are standardized to restore
function or replace but also include operational measures of restriction and emergency measures for securingsafety.
The basic flow for implementing maintenance efficiently and accurately is shown in Fig. 1.3.1.

(Initial, Periodic, Occasional, Re-install after removal Check,)(Daily check)

Preparation

Preparation(Accessories)(Rubber body)

Check

Check
Found
and
recorded

Find
deteriorations

No deterioration
found

Deterioration score

Check

Functiondeterioration

Deterioration rank

No deterioration

Deteriorated

No deterioration

Deteriorate

Check list

Check list

Check list

Check list

Measure PlanCountermeasures
Record and Save
Fig. 1.3.1 The basic flow for implementing maintenance7

Measure plan1.4 Checks
1.4.1 GeneralTo efficiently detect the deterioration that occurs in rubber fenders, it is necessary to perform planned and appropriate
checks and diagnoses. The checks and diagnoses of rubber fenders include an initial check and diagnosis, a daily check,a periodic check and diagnosis, and an occasional check and diagnosis depending on the purpose and implementation
timing. In the implementation of checks and diagnoses, to ensure the objectivity, reliability and consistency of theresults, check and diagnosis items, check and diagnosis methods, and judgement criteria must be defined in advance.
(1) Checks and diagnoses
For the proper maintenance and management of rubber fenders, planned and periodical checks and diagnoses
are essential, and the methods and results need to reliably evaluate the function of the rubber fenders.
(2) Classification of checks and diagnoses
The checks and diagnoses of rubber fenders are classified into initial check and diagnosis, daily check ,periodic check and diagnosis, and occasional check and diagnosis, as shown in Fig. 1.4.1, depending on the
purpose and time of implementation.
Initial check
Operation start

Periodic check

Visual check in daily
operation

Regular check in certain period

Occasional check
When damage or deterioration is found, or risk is
considered after abnormal berthing, abnormal motion ofmoored vessel, natural disasters such as earthquakes,
tsunami, fire, etc.

Abnormaloccasion

Check method
Reference
manualVisual check, eyemeasurement

Measurement, visual judgement by reference
photosSCOPE plannning guidelines

This guideline

Countermeasures

Daily check

Deterioration score and ranks

In normal
operation

The first check after installation

Fig. 1.4.1 Classification of checks and diagnoses(3) Items for checks and diagnoses
The check and diagnosis methods and deterioration scoring methods for ensuring the objectivity, reliability
and consistency of the inspection results are presented in Chapter 3. In principle, it is desirable to conduct
checks and diagnoses in accordance with this method and to objectively evaluate the impact on the function ofrubber fenders. On the other hand, inspections take place at height in a marine environment, and it is necessary
to consider safety and balance the cost and performance required for periodic and occasional inspections.
The items for checks and diagnoses for rubber fenders are shown in Table 1.4.1, and other rubber equipment items
are shown in Table 1.4.2.

8

Rubber body

Fixings

Accessories

Supports
Fender
panel
Resin
pad

Table 1.4.1 Items for checks and diagnoses for rubber fenders
RubberPneumatic fender
Deterioration
V-typefender
Cylindricalmode
fenderFloating
With panel
with panel
Drops
○
－
－
－
○
○
○
－
－
○
Tears
Permanent○○－－－
deformation
Missing rubber
○
－
－
－
○
Cracks○○○○○Chipping○－○－○
Separation
○
○
○
○
－
Wear
○
－
○
○
○
Ozone cracks
○
○
○
○
○
Cuts
－
－
○
○
－
Burns

○

○

○

○

○

Bolt hole damage

○

○

－

○

－

Loose
Bent
Missing
Cut
Corroded
Bent
Cut
CorrodedDeformation
Corrosion
Abrasion, Wear
Cut
Missing

○
○
○
○
○
－
－
－
－
－
－
－
－
－
－
－
－
－
－
－
－
－

○
○
○
○
○
○
○
○
○
○
○
○
○
○
－
－
－
－
－
－
－
－

－
－
－
－
－
－
－
－
－
－
－
－
－
－
○
○
○
○
○
○
○
○

○
○
○
○
○
○
○
○
○
○
○
○
○
○
－
－
－
○
○
－
－
－

－
－
－
－
－
○
○
○
－
－
－
－
－
－
－
－
－
－
－
－
－
－

BurnedMooring
parts

Others(Net, Air
inlet, etc.)

Bent
Cut
Corroded
InjuryCorrosion
Cut
Crack
Wear

9

Table 1.4.2 Items for checks and diagnoses other rubber equipment
Product

Rubber ladder

Cornerprotector

Rubber net

Drops

○

－

－

Tears

○

－

－

Permanent deformation

○

○

－

Missing rubber

○

○

－

Fixings

Rubber body

Deterioration mode

Cracks○○－Chipping○○－

Separation

○

○

－

Wear

○

○

－

Ozone cracks

○

○

－

Cuts

○

－

○

Burns

○

○

○

Bolt hole damage

○

○

○

Loose

○

○

○

Bent

○

○

○

Missing

○

○

○

Cut

○

○

○

Corroded○○○

1.4.2 Initial check
The initial checks are conducted to assess the condition of the rubber fenders immediately after installation or at thestart of the maintenance stage. It is ideal to use a scale for measurement, but when this is difficult, measurement by
visual observation may be acceptable.
1.4.3 Daily check
The daily check is a routine inspection of a rubber fender to assess the deterioration of the fender by daily protocol.
If deterioration is detected, it is necessary to proceed to the implementation of occasional inspection and diagnosis. The
daily check corresponds to a protocol that a manager or user of fenders carries out on a daily basis and is carried out topay regular attention to any damage or deterioration. The inspection method in this case may be visual inspection by
walking.
1.4.4 Periodic check
Periodic checks and diagnoses are conducted regularly to determine any deterioration, with the aim of detecting theoccurrence as quickly as possible and any progress of deterioration caused by the use of rubber fenders. Periodic
checks and diagnoses should be carried out systematically and continuously based on a predetermined inspection plan.
They should be conducted at least once a year or planned appropriately according to the importance of the facility.
It is desirable to use a scale for measuring and determining the deterioration of a fender, but if this is difficult, visual
measurement may be used.
1.4.5 Occasional checkOccasional checks and diagnoses are conducted to confirm the damage of fenders when deterioration is recognized
during daily inspection, abnormal berthing, excessive vessel motion, etc., or when there is a possibility of being

10

affected by an earthquake, tsunami, fire, etc.
In carrying out occasional checks and diagnoses, it is necessary to measure the deterioration that has occurred in therubber fender according to the periodic check and diagnosis and confirm the degree of deterioration.

1.5 Functional evaluation and measures
1.5.1 General
Based on the check and diagnosis results, functional evaluation is performed based on the determination of thedeterioration score and deterioration rank of the rubber fenders, and appropriate measures should be considered. In
functional evaluation, damage and deterioration over service time is examined in each rubber fender to determine how
it occurred, how it progressed and whether to consider measures be taken as necessary.
1.5.2 Functional evaluation
In the functional evaluation of rubber fenders, deterioration rank and deterioration score are determined based on
check and diagnosis results. During daily inspection, the deterioration rank is judged in four stages—a, b, c andd—based on the CDIT maintenance manual. If the deterioration rank is a, occasional inspection and diagnosis must be
conducted. The initial check and diagnosis, periodic check and diagnosis, and occasional check and diagnosis
parameters are based on this guideline. For the rubber body, the deterioration score is calculated by measuring thedamaged parts, and for accessories, the deterioration rank is determined by a visual condition of each part.
Chapter 3 shows how to determine the degradation rank and degradation score of the rubber fenders.
1.5.3 Countermeasures
Based on the results of the functional evaluation, appropriate measures are implemented as necessary. If it isdetermined that some measures are necessary now or in the future, it is necessary to make a plan of measures after
taking into consideration the service period of the facility and necessary costs in the future. Chapter 4 outlines thesemeasures.
In making comprehensive judgements after checking and diagnosing leading up to countermeasures, past records ofthe conditions and technical knowledge about countermeasures at other ports are helpful.
1.5.4 Life-cycle cost
To maintain rubber fenders effectively and economically, it is desirable to consider the life-cycle cost related to themaintenance of the entire facility to appropriately maintain rubber fenders. If the function of the fender decreases due
to deterioration, it may be necessary to suspend the operation of the mooring facility and port traffic facility, which
may cause a loss due to the operation shutdown of the facility. Therefore, the proper maintenance and management ofrubber fenders contributes to the optimization of the life cycle cost of the entire facility.
The life cycle cost of the entire facility shall be considered in accordance with the CDIT maintenance manual.

1.6 Recording and saving data
It is necessary to record and save various data related to the maintenance of checks and diagnoses, functional
evaluations, measures, etc. according to a certain format. These maintenance management records are basic
information for performing appropriate evaluations and measures of fender function and are useful for the maintenancemanagement of other similar facilities.

〔References〕
1) PIANC：Guidelines for the Design of Fenders System, Report of Working Group 33 of the Maritime Navigation
Commission, 2002

11

Chapter 2
Deterioration factor and deterioration mode of rubber fenders
2.1 Summary
2.1.1 General
The degradation factor of rubber and deteriorating factors of accessories must be considered. The deterioration
factors of rubber fenders are classified into natural environmental factors, chemical factors, fatigue factors, andexternal force factors.
(1) Rubber deterioration phenomena and factors
The deterioration factors of rubber include natural environmental factors, chemical factors, fatigue factors andexternal force factors. A systematic summary of deterioration factors and phenomena is shown in Fig. 2.1.1 1).

《Deterioration modes》

Natural environmental factors

Drop
Light

Heat・Oxidation

Air

Water・Sea water

Tear

Sun

Ozone

Radiant heat

Rain

Permanent deformation

Ultraviolet

OxygenTemperature

waves

Missing rubber

Combustion

Snow

Crack

Deterioration of rubber

Chipping

Volatilization
StaticSeparation

Extraction

DamageWear

Dynamic

Swelling

Breakage

Ozone cracks

Fatigue

Oil・Solvent

Destruction by external force

Cut

Fatigue factor

Chemical factor

External force factor

Bolt hole damage

Burn

Fig. 2.1.1 Deterioration phenomenon and factors of rubber(2) Deterioration phenomena and factors of accessories
There are natural environmental factors, chemical factors, fatigue factors and external force factors involvedin the deterioration of accessories. These accessories include steel members (fixing parts, supporting parts,
fender panels, anchoring parts), resin pads and so on.

2.1.2 Deterioration factors of rubber fenders
The deterioration factors of rubber fenders are categorized as deteriorations of rubber bodies and accessories.
(1) Deterioration factor of rubber body
1) UV (Ultraviolet) deterioration
Ultraviolet light in sunlight has a wavelength of 290 to 400 nm and provides energy for dissociating
bonds of organic compounds, and this dissociation is called ultraviolet light deterioration. UV deterioration
is significantly accelerated in the presence of oxygen, such as thermal and oxidative deterioration.
Therefore, ultraviolet deterioration occurs only on the surface where oxygen is present and the ultraviolet
light directly strikes. Since rubber fenders contain carbon black, ultraviolet rays do not reach inside therubber, and deep parts of the body are less likely to be deteriorated by ultraviolet rays.
2) Ozone deterioration
12

Ozone contained in the air reacts with unsaturated double bonds in rubber to cause cleavage of themolecular chain. When rubber is used in tension, sharp cracks similar to razor cuts occur on the surface. Thisphenomenon is called ozone cracking (ozone deterioration). In the case of rubber fenders, since diene rubber,such as natural rubber (NR) or styrene butadiene rubber (SBR), is used, ozone deterioration is limited to thesurface in contact with ozone in the air.
3) Thermal and oxidative deterioration
When rubber is maintained for a long time at a certain temperature with oxygen, the autoxidation reactionof the polymer progresses. The phenomenon where rubber materials change, such as deterioration due toautoxidation reaction, discoloration, cracks, etc., is called thermal and oxidative deterioration. Since rubber
used for fenders has low thermal conductivity and low oxygen permeability, thermal and oxidative
deterioration is mainly limited to the surface. When rubber is damaged by fire, carbonization proceeds fromthe surface depending on the degree of damage.
4) Seawater deterioration
Swelling and modulation of rubber that has been exposed to seawater for a long time is called seawater
deterioration. However, since the rubber fender is made from a diene rubber, such as natural rubber (NR) or
styrene butadiene rubber (SBR), it is stable against seawater (water). Most rubber formulas have long beenused for waterproofing and water-resistant applications due to their low swelling with seawater.
5) Chemical deterioration
Natural rubber (NR) and styrene butadiene rubber (SBR) swell when in contact with oils and solvents. Thisphenomenon is called chemical deterioration. Oils and solvents generally float on the surface of water due totheir small specific gravity, but it is unlikely they would come in constant contact with rubber fenders.
6) Fatigue deterioration
Even with small strains or stresses, cracks are generated and develop through repetition. The phenomenon
in which the strength characteristics gradually decrease due to creep or stress relaxation is called fatigue
deterioration. The fatigue deterioration of a rubber fender changes the reaction force, causing a decrease in
the necessary amount of energy absorption.
7) Destruction due to external force
External deterioration that causes rubber to be subjected to breaking strain or force exceeding breaking
stress and causes cracks or breaking is referred to as destruction by external force. In the case of rubber
fenders, sudden destruction such as cracking and breakage are caused by the abnormal berthing of vessels,
excessive deformation by vessels, etc., as well as hooking and rubbing due to projections or irregularities on
the hull of vessels. In addition, due to repeated vertical and horizontal movements due to the motion of avessel during mooring, an uneven portion on the surface of the vessel comes in contact with the surface ofthe fender, and the rubber portion is repeatedly attacked, and damage to the rubber gradually progresses.
(2) Deterioration factor of accessories
1) Steel member
Corrosion:
Corrosion occurs when metal is altered or consumed from the surface by chemical reactions withwater, oxygen, etc. This change in the steel members of rubber fenders is called corrosion deterioration.
As shown in Fig. 2.1.2, five corrosive environments are classified according to the installation positionof the steel structure. Since rubber fenders are installed in a "splash zone", "tidal zone" and "in the sea"
where the corrosive environment is severe, special attention is required for corrosion and deterioration.
In general, steel members installed in places with severe corrosive environments need to be plated(galvanized, aluminized) or painted (epoxy resin, etc.) on the surface. In addition, stainless steel may be
13adopted as a corrosion-resistant material.

Fig. 2.1.2 Corrosion speed of steel in coastal area2)
Deterioration by external force:
When an external force that exceeds the stress assumed in design is applied to steel material, breakage
or damage occur, causing deterioration of the fender system. This is called deterioration by external
force.
2) Resin pad and others
Ageing deterioration:
A phenomenon in which the function and performance of a member deteriorate over time due to thenatural environment and fatigue in use is called ageing deterioration.
Deterioration by external force:
When an external force exceeding the stress assumed in design is applied to a member, breakage ordamage occur, causing deterioration. This is called deterioration by external force.

142.1.3 Deterioration modes of rubber fenders
The deterioration modes of rubber fenders, bodies and accessories are as follows.
Rubber body: Drops, tears, permanent deformation, missing rubber, cracks, chipping, separation, wear,
ozone cracks, cuts, burns, bolt hole damage
Accessories: loose, bent, missing, cuts, corrosion, abrasion and wear, tears, cracks(1) Rubber body of fender
The rubber body has different deterioration modes depending on the type of rubber fender. The
deterioration modes for each type of rubber fender are shown in Table 2.1.1.
Table 2.1.1 Deterioration modes for rubber fenders
FenderV-typefenderRubber fenderwith panel

Drops

○

Tears

Deterioration mode

Pneumatic fender
Cylindrical
Floating

With panel

－

－

－

○

○

○

－

－

○

Permanent deformation

○

○

－

－

－

Missing rubber

○

－

－

－

○

Cracks

○

○

○

○

○

Chipping

○

－

○

－

○

Separation

○

○

○

○

－

Wear

○

－

○

○

○

Ozone cracks

○

○

○

○

○

Cuts

－

－

○

○

－

Burns

○

○

○

○

○

Bolt hole damage

○

○

－

○

－

15

(2) Fender accessories
Accessories are classified into fixings, supports (including chains), fender panels, resin pads, mooringparts, and others (net, air injection valve, etc.). Each degradation mode is shown in Table 2.1.2.
Table 2.1.2 Deterioration modes of accessories
FenderParts

Fixings

Supports
Fenderpanel

Resin pad

Burns

Mooring
parts

Others(Net, Air inlet,
etc.)

Rubberfenderwith panel

Floating

With panel

○
○
○
○
○
－
－
－
－
－
－
－
－
－
－
－
－
－
－
－
－
－

○
○
○
○
○
○
○
○
○
○
○
○
○
○
－
－
－
－
－
－
－
－

－
－
－
－
－
－
－
－
－
－
－
－
－
－
○
○
○
○
○
○
○
○

○
○
○
○
○
○
○
○
○
○
○
○
○
○
－
－
－
○
○
－
－
－

Mode
Loose
Bent
Missing
Cut
Corroded
Bent
Cut
CorrodedDeformation
Corrosion
Abrasion/Wear
Cuts
Missing
Bent
Cut
Corroded
Malfunction
Corroded
Cuts
CracksWear

Pneumatic fender

V-typefender

Cylindrical

－
－
－
－
－
○
○
○
－
－
－
－
－
－
－
－
－
－
－
－
－
－

2.1.4 Deterioration modes of other rubber equipment
Other rubber equipment used in ports includes rubber ladders, corner protectors, rubber nets, etc., each of which has
the following deterioration modes regarding rubber bodies and accessories.
Rubber body: Drops, tears, permanent deformation, missing rubber, cracks, chipping, separation, wear, ozone
cracks, cuts, burns, bolt hole damage
Accessories (fixings): loose, bent, missing, cut, corroded(1) Rubber bodies of other rubber equipment
Typical deterioration modes of other rubber bodies are shown in Table 2.1.3.

16

Table 2.1.3 Deterioration modes of rubber bodies of other rubber equipment
Product
CornerRubber ladderRubber net
protector
Deterioration mode
Drops

○

－

－

Tears

○

－

－

Permanent deformation

○

○

－

Missing rubber

○

○

－

Cracks○○－Chipping○○－

Separation

○

○

－

Wear

○

○

－

Ozone cracks

○

○

－

Cuts

○

－

○

Burns

○

○

○

Bolt hole damage

○

○

○

(2) Accessories (Fixings) of other rubber equipment
Typical deterioration modes of accessories are shown in Table 2.1.4.
Table 2.1.4 Deterioration modes of accessories of other rubber equipment
Product

Rubber ladder

Cornerprotector

Rubber net

Loose

○

○

○

Bent

○

○

○

Missing

○

○

○

Cut

○

○

○

Corroded○○○

Deterioration mode

2.2 V-type rubber fender
2.2.1 Configuration of V-type rubber fender
V-type rubber fenders are divided into V-type and pivoted V-type according to their shapes. The member iscomposed of a rubber body and accessories (fixings). The rubber body of a V-type rubber fender comprises a rubber
body portion and a fixing portion (fixing flange), and steel plates are embedded in the fixing flange. The names of eachpart are shown in Fig. 2.2.1 (V-type) and Fig. 2.2.2 (pivoted V-type).
(1) V-type rubber fender
Rubber body
Fixings

17

Fig. 2.2.1 Configuration of V-type rubber fender(2) Pivoted V-type rubber fender (Circle)
Rubber body
Fixings

Fig. 2.2.2 Configuration of pivoted V-type rubber fender

2.2.2 Deterioration modes of V-type rubber fender
Deterioration modes regarding V-type rubber fenders are as follows.
Rubber body: Drops, tears, permanent deformation, missing rubber, cracks, chipping, separation, wear, ozone
cracks, cuts, burns, bolt hole damage
Accessories (fixings): loose, bent, missing, cut, corroded18

(1) Rubber body1) Drops"Drops" are the progressive defects of cracking and missing rubber, leaving no rubber present in the faceand legs of the rubber body, with the defect eventually reaching hollow space, as shown in Photo 2.2.1

Photo 2.2.1 Drop of a rubber body2) Tears
As shown in Photo 2.2.2, cracks in the face and legs of the rubber body progress and reach a hollow partcalled a "Tear".

Photo 2.2.2 Tear of a rubber body193) Permanent deformation
As shown in Photo 2.2.3, a condition in which the face, legs, or fixing flange of a rubber body are
deformed and do not return to their original shape is called "Permanent deformation".

Photo 2.2.3 Permanent deformation of a rubber body4) Missing rubber
As shown in photo 2.2.4, when chunks of rubber are scraped off at the face of the rubber body, but thedefect has not reached the hollow part, This is called "Missing rubber".

Photo 2.2.4 Missing rubber from rubber body205) Cracks
As shown in Photo 2.2.5, the rubber surface is partially cut at the face and legs of the rubber body, but
the defect does not reach the hollow part; these are called "Cracks".

Photo 2.2.5 Cracks in rubber body6) Chipping
As shown in Photo 2.2.6, the condition where the rubber surface is damaged in a dotted manner on theface of the rubber body is called "Chipping".

Photo 2.2.6 Chipping of rubber body217）Separation
As shown in Photo 2.2.7, the condition where rubber parts on surface and side of fixing flange are
separated from the embedded steel plate is called "Separation".

Photo 2.2.7 Separation of rubber body8) WearAs shown in Photo 2.2.8, the condition in which corners of face of rubber body are worn away (rounded)is called "Wear".

Photo 2.2.8 Wear of rubber body229) Ozone cracks
As shown in Photo 2.2.9, innumerable small cracks are generated on the surface of the rubber body, legs,
hollow space, and fixing flange, which are called "ozone cracks".

Photo 2.2.9 Ozone cracks on a rubber body10) Burns
As shown in Photo 2.2.10, a condition where the rubber body is damaged by heat, such as fire, and thesurface is carbonized is called a "Burn".

Photo 2.2.10 Burn of rubber body11) Bolt hole damage
As shown in photo 2.2.11, a condition in which the bolt hole is damaged by external force or corrosion iscalled "Bolt hole damage".

23

Photo 2.2.11 Bolt hole damage to a rubber body(2) Accessories (Fixings)
1) Loose
As shown in photo 2.2.12, the condition where bolt (nut) is loose is called "Loose."

Photo 2.2.12 Loose fixing bolt (Accessories)
Note 1:
Note 2:

If a bolt (nut) is used loose, there is a risk of damaging the rubber body (leg) or vessel hull,
so retightening is necessary.
Since it is possible to prevent the looseness of a bolt (nut) by spot welding the bolt(nut) and washer after tightening, it is recommended to do so.

2) BendAs shown in photo 2.2.13, a large force is applied to fixing the bolt, and the state in which the bolt isbent is called a "Bend".

24

Photo 2.2.13 Bent fixing bolt (Accessories)3) Missing
As shown in photo 2.2.14, the state of loosening of fixing bolt progresses and it falls off, or bolt itself
comes out, and it does not play the role of suppressing the fenders, it is called "Missing".

Photo 2.2.14 Missing fixing bolt (Accessories)
Note 1:The loosening of a fixing bolt is gradually advancing before coming off, and it can beprevented by retightening when loosening is found.
Note 2: If a fender is used without bolts, an excessive load is placed on other remaining bolts, andthere is a risk of accelerating failure of the fender system, so an immediate repair isnecessary.
Note 3: Care should be taken, as poor concrete strength and poor anchor installation can also lead to"missing" bolts.
4) Cuts
As shown in photo 2.2.15, the broken state of the bolt due to excessive external force applied to the bolt
is called a "Cut".

Photo 2.2.15 Cut fixing bolt (Accessories)

25

Note 1:

If a fender is used without bolts, an excessive load is placed on other remaining bolts, andthere is a risk of accelerating failure of the fender system, so an immediate repair isnecessary.

5) Corrosion
As shown in photo 2.2.16, a state where rusting has occurred and progressed on fixing bolts is called"Corrosion".
Corrosion progress
No corrosion

Discoloration

Discoloration of bolt
and
red rust on washer

Red rust

Red rust swell

Photo 2.2.16 Corrosion of fixing bolt (Accessories)

2.3 Rubber fender with fender panel
2.3.1 Configuration of rubber fender with panel
Rubber fenders with fender panels are fenders that absorb the berthing energy of a vessel by buckling deformation of
the rubber body and are divided into longitudinal (rectangular) and circular types according to their shapes. The
member is composed of a rubber body and a steel fender panel installed on the front surface of the rubber body and26other accessories (fixing, support and resin pad). The rubber body of the fender with a panel is composed of a rubber
body, a fixing flange and a steel plate embedded in a fixing flange.
(1) Rubber fender with panels (Longitudinal)
The configuration of a rubber fender with panels (longitudinal) is shown in Fig. 2.3.1.
1) Rubber body2) Fender panel
3) Fixing4) Support
5) Resin pad

Fig. 2.3.1 Configuration of longitudinal rubber fender with panel(2) Rubber fender with panels (Circular)
The configuration of a rubber fender with panels (Circular) is shown in Fig. 2.3.2.
1) Rubber body2) Fender panel
3) Fixing4) Support
5) Resin pad

27

Fig. 2.3.2 Configuration of longitudinal rubber fender with panel

2.3.2 Deterioration modes of rubber fender with panel
The degradation modes of a rubber fender with a panel are as follows.
Rubber body: tears, permanent deformation, cracks, separation, ozone cracks, burns, bolt hole damage,
Panel: deformation, corrosion,
Fixing: loose, bent, missing, cut, corroded
Support: bent, cut, corroded
Resin pad: wear, abrasion, cut, missing, burn(1) Rubber body1) Tears
As shown in Photo 2.3.1, a crack occurring in the rubber body that has progressed and reached ahollow part is called a "tear".

Photo 2.3.1 Tear of rubber body282) Permanent deformation
As shown in Photo 2.3.2, a condition in which the rubber body and fixing flange are deformed and do
not return to their original shape is called a "permanent deformation".

Photo 2.3.2 Permanent deformation of a rubber body3) Cracks
As shown in Photo 2.3.3, a condition where the rubber body is partially cut on the surface but does notreach the hollow part is called a "crack".

Photo 2.3.3 Crack in rubber body4) Separation
As shown in Photo 2.3.4, a condition where the rubber part of a surface or the side of a fixing flange ofa rubber body is peeling off from the embedded steel plate is called a "separation".

Photo 2.3.4 Separation of rubber body295) Ozone cracks
As shown in Photo 2.3.5, innumerable small cracks on the surface of the rubber body are called "ozone
cracks".

Photo 2.3.5 Ozone cracks on a rubber body6) Burns
As shown in Photo 2.3.6, a rubber body damaged by heat, such as fire, with a carbonized surface of therubber body is called a "burn".

Zoom

Photo 2.3.6 Burn of rubber body7) Bolt hole damage
Refer to Photo 2.2.11 Bolt hole damage of a rubber body.
(2) Fender panel
1) Deformation
As shown in Photo 2.3.7, the state of plastic deformation of a fender panel or a part of it by the actionof an external force is called "deformation".

30

Photo 2.3.7 Deformation of a fender panel2) Corrosion
As shown in Photo 2.3.8, a state where rust has occurred and has progressed is called "corrosion".

Photo 2.3.8 Corrosion of a fender panel(3) Fixings
1) Loose
As shown in Photo 2.3.9, a condition where a bolt or nut is loose is called "loose."31

Photo 2.3.9 Loose fixing bolt
2) BendAs shown in Photo 2.3.10, a condition where a fixing bolt is bent due to an excessive external force isconsidered a "bent".

Photo 2.3.10 Bent fixing bolt3) Missing
As shown in Photo 2.3.11, when the loosening of an anchor bolt progresses and falls off, or theanchor itself is pulled out, it is considered "missing".

32

Photo 2.3.11 Missing fixing bolt4) Cuts
As shown in Photo 2.3.12, when a fixing bolt is subjected to excessive external force, the broken stateis called a "cut".

Photo 2.3.12 Cut fixing bolt5) Corrosion
As shown in Photo 2.3.13, the occurrence and progression of rust is called "corroded".

Photo 2.3.13 Corrosion of fixing bolt

33

(4) Supports
1) BendAs shown in Photo 2.3.14, an excessive external force is applied to supporting parts, and the state inwhich the part is bent is referred to as "bent".

Photo 2.3.14 Bent support (Adjustable U-shape shackle)
2) CutAs shown in photo 2.3.15, the support part is subjected to excessive external force and broken. This stateis called "cutting".

Photo 2.3.15 Cut of support (Chain shackle)
3) Corrosion
As shown in photo 2.3.16, the state where rust has occurred and has progressed is called "corroded".

Photo 2.3.16 Corrosion of support (Chain)34

(5) Resin pad1) Abrasion/WearAs shown in Photo 2.3.17, a condition where abrasion has occurred on the surface of the resin pad due tothe contact of the vessel is called “abrasion/wear”.

Photo 2.3.17 Abrasion/wear of resin pad2) CutAs shown in Photo 2.3.18, a state where a crack has occurred in some resin pads due to the attack of a
sharp load is called a "cut".

Photo 2.3.18 Cut of resin pad3) Missing
As shown in Photo 2.3.19, a state in which a part or all of resin pads fall off due to external load is called"missing”.

Photo 2.3.19 Missing resin pad

354) Burn
As shown in Photo 2.3.20, a condition where the resin pad is melted or burned off by heat, such as fire,is called a "burn".

Photo 2.3.20 Burned resin pad

2.4 Pneumatic fender
2.4.1 Configuration of pneumatic fender
Pneumatic fenders absorb the energy of a berthing vessel using the elasticity of air filled in a fabric-reinforced
rubber bag; there are two types: a floating pneumatic fender and a fixed pneumatic fender with a panel. The member iscomprised of a rubber body (bag) and accessories. The rubber body of a floating pneumatic fender is only a rubber bag,but the fixed pneumatic fender with fender panel consists of a rubber bag and a fixing part (fixing flange), and steel
plates are embedded in the flange. The rubber body of the pneumatic fender is composed of an outer rubber layer, areinforcing layer and an inner rubber layer.
(1) Floating-type pneumatic fender
A floating pneumatic fender is composed of a rubber body and accessories (air inlet valve, body attachment,
net, mooring attachment). The names of each part are shown in Fig. 2.4.1.
1) Rubber body2) Air inlet valve3) Body attachment (base, cover plate, hanging parts)
4) Net5) Mooring attachment

36

Fig. 2.4.1 Configuration of floating pneumatic fender(2) Fixed-type pneumatic fender with panel
A fixed-type pneumatic fender with a panel is composed of a rubber body and accessories (air inlet valve,body attachment, fender panel, fixing, support, resin pad). The names of each part are shown in Fig. 2.4.2.
1) Rubber body2) Air inlet valve3) Body attachment (valve protector)
4) Fender panel, fixings, supports, resin pad

Fig. 2.4.2 Configuration of fixed-type pneumatic fender37

2.4.2 Deterioration modes of pneumatic fender
The deterioration modes of pneumatic fenders are as follows.
Rubber body: cracks, chipping, separation, wear, ozone cracks, tears, burns, bolt hole damage
Air inlet valve: damage, corrosion
Body attachment: malfunction, corrosion
Net: corrosion, cuts, cracking, wear, burns
Mooring attachment: fender panel, support and resin pad: corrosion, etc.
(1) Rubber body1) Cracks, chipping
As shown in Photo 2.4.1, the outer rubber layer and part of the reinforcing layer are partially cut, but
the inside of the bag is not pierced, which is called "cracking". In addition, the state where the rubber
surface is finely damaged is called "chipping".

Photo 2.4.1 Cracking and chipping of rubber bodyNote) In the case of the crack in this photo, a reinforcement layer is exposed. Perform occasional check anddiagnosis as soon as possible because of the risk of decreased pressure resistance.
2) Separation
As shown in Photo 2.4.2, the rubber covering the embedded steel plate to which an air inlet valve isattached is separated, or as shown in Photo 2.4.3, the state in which a part is separated is called"separation".

Photo 2.4.2 Separation of rubber body (Embedded plate)38

Photo 2.4.3 Separation of rubber body (Outer layer)Note) In the case of separation in this example, the reinforcing layer is exposed. Perform occasional checkand diagnosis as soon as possible because of the risk of a drop in pressure resistance.
3) WearAs shown in Photo 2.4.4, the condition in which the outer rubber layer is rubbed and the reinforcing layer
becomes visible, or in which the reinforcing layer is also worn, is referred to as "wear".

Photo 2.4.4 Wear of rubber bodyNote) In this example, since multiple reinforcing layers are worn, the required pressure resistance may besignificantly reduced. Stop using immediately and carry out occasional check and diagnosis.
4) Ozone cracks
As shown in Photo 2.4.5, an infinite number of small cracks are generated on the surface of the outerrubber layer are referred to as "ozone cracks".

39

Photo 2.4.5 Ozone cracks on rubber body5) Tears
As shown in Photo 2.4.6, the outer rubber layer, reinforcing layer and inner rubber layer are cut, and thecondition in which injury reaches the inside of the rubber bag is called a "tear".

Photo 2.4.6 Tear of rubber body6) Burn
The situation of burns on the surface, in the case of fire, is similar to the case of Photo 2.3.6 Burn of
rubber body.

7) Bolt hole damage (Fixed type)The degradation form of bolt hole damage conforms to Photo 2.2.11 Bolt hole damage of rubber body.

(2) Air inlet valve
1) Malfunction
As shown in Photo 2.4.7, a state in which an abnormality such as deformation, screw failure or air leakhas occurred is called a "malfunction".

40

Photo 2.4.7 Malfunction of air inlet valve2) Corrosion
As shown in Photo 2.4.8, the state where rust has occurred and has progressed is called "corroded".

Photo 2.4.8 Corrosion of air inlet valve(3) Body attachment
As shown in Fig. 2.4.3, the main body attachment includes an air valve, flange plate and hanging metal.

Fig. 2.4.3 Body attachment (floating type)41

1) Malfunction
As shown in Photo 2.4.9, a state in which an abnormality such as deformation, cutting, or screw failure
has occurred is called a "malfunction".

Photo 2.4.9 Malfunction of body attachment

2) Corrosion
As shown in Photo 2.4.10, the state where rust has occurred and has progressed is called "corroded".

Photo 2.4.10 Corrosion of body attachment(4) Net (Floating type)
The net is a protective member that covers the main rubber body and is used to secure fenders safely. The
net is composed of net members such as chains, wires, ropes and shackles, protective tyres (used tyres) andrubber sleeves.
1) Corrosion
As shown in Photo 2.4.11, the state where rust has occurred and has progressed is called "corroded".

42

Photo 2.4.11 Corrosion of net
2) Cuts
As shown in Photo 2.4.12, a net that is broken due to excessive external force applied to the net isconsidered "cut". This also includes a condition where a shackle has fallen off and part of net has comeoff.

Photo 2.4.12 Cut net
3) Tears
A condition where the tyre and rubber sleeve are broken is called a "tear", as shown in Photo 2.4.13.

Photo 2.4.13 Torn net

434) Wear
As shown in Photo 2.4.14, a condition where the tyre and rubber sleeve are worn away, the fibre layer is
exposed (in the case of a tyre) or extends to the hollow part is called "wear".

Photo 2.4.14 Wear of net
5) Burns
A condition where tyres and rubber sleeves are damaged by heat, such as fire, and the surface is carbonizedis considered a "burn".

(5) Mooring attachment
The deterioration modes (bent, cut, corroded) of the mooring attachment (in floating types) shall be inaccordance with 2.3.2 Deterioration modes of rubber fender with panels (3) and (4). In addition, thedegradation modes of the fender panel, fixings, supports, and resin pad (in fixed types with a fender panel)
conform to 2.3.2 Deterioration modes of rubber fender with panels (2) to (5).

2.5 Cylindrical fender
2.5.1 Configuration of cylindrical fender
A cylindrical rubber fender is comprised of a cylindrical rubber body and accessories for installation on the quay.
The names of each part for the rubber body and supports (chain, steel bar, U-shape anchor) are shown in Fig. 2.5.1.

Fig. 2.5.1 Configuration of cylindrical rubber fender44

2.5.2 Deterioration modes of cylindrical fender
The deterioration modes of cylindrical rubber fenders include the following.
Rubber body: drops, cracks, missing rubber, tears, chipping, wear, ozone cracks, burns
Supports: bent, cut, corroded(1) Rubber body1) Cracks
As shown in Photo 2.5.1, a condition from which a scratch from the outside of the rubber bodyadvances and reaches the hollow space is called a "crack".

Photo 2.5.1 Crack of rubber body2) Missing rubber
As shown in Photo 2.5.2, when the rubber is scraped off from outside of the rubber body but has notreached the hollow space, this is considered "missing rubber".

Photo 2.5.2 Missing rubber from rubber body3) Ozone cracks
As shown in Photo 2.5.3, when numerous small cracks are generated on the surface of the rubber
body, these are considered "ozone cracks".

45

Photo 2.5.3 Ozone cracks in rubber body4) Drops, tears, chipping, wear and burns
These deterioration modes are based on 2.2.2 Deterioration modes of V-type rubber fenders (1).
(2) Supports
1) Corrosion
As shown in Photo 2.5.4, the state where rust has occurred and has progressed is called "corroded".

Photo 2.5.4 Corrosion of support
2) Bends, cuts
These deterioration modes are based on 2.3.2 The degradation modes of rubber fenders with panels (4).

2.6 Other rubber equipment
2.6.1 Configuration of other rubber equipment
Rubber ladders, corner protectors and rubber nets consist of respective rubber bodies and accessories. The
configurations of these items are shown below.
(1) Rubber ladders
A rubber ladder is a safety item for fall prevention that is composed of a rubber body and accessories(Fixings). The names of each part are shown in Fig. 2.6.1.
46

Fig. 2.6.1 Configuration of rubber ladder(2) Corner protectors
A corner protector is a member that protects the quay top end corner. A corner protector consists of arubber body and accessories (fixings). The names of each part are shown in Fig. 2.6.2.

Fig. 2.6.2 Configuration of corner protector(3) Rubber nets
A rubber net is a member that prevents vessels, driftwood and people from getting into the opening infront of quay. A rubber net consists of a rubber body and accessories (Fixings). The names of each part are
shown in Fig. 2.6.3.

47

Fig. 2.6.3 Configuration of rubber net

2.6.2 Deterioration modes of other rubber equipment
The deterioration modes of other rubber equipment include the following.
Rubber body: drops, cracks, permanent deformation, missing rubber, cuts, chipping, separation, wear, burns, bolt
hole damage, ozone cracks and tears.
Fixings: loose, bent, missing, cut and corroded.
(1) Rubber body1) Rubber laddera. Drops
As shown in Photo 2.6.1, the progress of cracking and breakage in which there is no rubberpresent in the rubber body and the absence reaches the hollow space is called a "drop".

Photo 2.6.1 Drop of rubber bodyb. Tears
As shown in Photo 2.6.2, a crack occurring in the rubber body that has progressed and reachedthe hollow space is called a “tear”.

48

Photo 2.6.2 Tear of rubber bodyc. Permanent deformation
As shown in Photo 2.6.3, a condition in which the rubber body and fixing flange are deformed
and do not return to their original shape is called a "permanent deformation".

Photo 2.6.3 Permanent deformation of a rubber bodyd. Missing rubber
As shown in Photo 2.6.4, although rubber is scraped off at the rubber body, the state where it
does not reach the hollow space is called “missing rubber”.

49

Photo 2.6.4 Missing rubber from rubber bodye. Cuts
As shown in Photo 2.6.5, a condition where the ladder is exposed to excessive external force,
etc., and the step portion of the ladder is peeled off is called a "cut". This also includes thesituation where a portion of the steps is out.

Photo 2.6.5 Cut of rubber bodyf. Tears, chipping, separation, wear, ozone cracks, burns and bolt hole damage are similar to 2.2.2
Deterioration modes of V-type rubber fenders (1) Deterioration modes.
2) Corner protectors
Permanent deformation, missing rubber, tears, chipping, separation, wear, ozone cracks, burns and bolt
hole damage are similar to 2.2.2 Deterioration modes of V-type rubber fenders (1) Deterioration modes.
3) Netsa. Cuts
As shown in Photo 2.6.6, a condition where an excessive external force is applied to rubber net anda part of the body is peeled is called a "cut".

50

Photo 2.6.6 Cut of rubber ladder(2) Fixings
The deterioration modes of rubber ladders are similar to 2.2.2 Deterioration modes of V-type rubber
fenders (2) Fixings.

〔References〕
1) Nakauchi, H.: Deterioration of rubber composites, Journal of The Society of Rubber Industry, Japan Vol. 64, No. 9,
1991 (Japanese)2) Coastal Development Institute of Technology (CDIT): Manual on Corrosion Prevention and Repair for Ports andHarbor Steel Structure, No. 35, 2009 (Japanese)
3) Terauchi, K., T. Koizumi, S. Yamamoto, K. Hosokawa: Deterioration Actual State and the Function Evaluation of the
Rubber Fender, Technical Note of the Port and Harbour Research Institute, Ministry of Transport, Japan, No. 878,
1997 (Japanese)
4) Association for Innovative Technology on Fishing Ports and Grounds: Fender Replacement Criteria for Fishing Ports(Draft) (Functional evaluation document), 2007 (Japanese)51

Chapter 3
Check diagnosis and functional evaluation of rubber fender
3.1 General
3.1.1 Summary
To check and diagnose rubber fenders, the initial check and diagnosis, daily check, periodic check and diagnosis, andoccasional check and diagnosis shall be carried out. Based on the results, a functional evaluation shall be performed
using the following methods.
Daily check:
The deterioration rank is determined based on the condition of parts and components of both the rubber bodyand accessories.
Initial check and diagnosis, periodic check and diagnosis and occasional check and diagnosis:
For the rubber body, the deterioration score is judged on the basis of measurement of the damaged part. When
re-installing the removed rubber fender, consider the functional evaluation according to the condition of bolt
hole damage. For accessories, the deterioration rank is determined based on the condition of the parts andmembers.
(1) Daily checks
The purpose of a daily check is to assess the presence or absence of deterioration in fenders through daily
inspections (1.4, Chapter 1), but in this guideline, the deterioration rank is determined in four stages—a, b, c andd—by visual judgement as in the CDIT maintenance manual. The criteria for determining deterioration rank areshown in Tables 3.1.1–3.1.5 for each fender type. If the deterioration is ranked a, an occasional check anddiagnosis must be conducted. Additionally, if the deterioration rank is c, plans shall be made for checks anddiagnoses. Note that there is nothing that falls under deterioration rank b in the CDIT maintenance manual.
1) V-type rubber fenders
Table 3.1.1 Deterioration rank and mode of daily checks (V-type rubber fenders)
Rank
Deterioration mode of parts
Rubber body: drops, cracks, permanent deformation, burnsaAccessories (fixings): loose, bent, missing or cutb-----Rubber body: missing rubber, cracks, chipping, separation, wear, ozoneccracksAccessories (fixings): corrodeddNo deterioration

522) Rubber fenders with panel
Table 3.1.2 Deterioration rank and mode of daily checks (Rubber fenders with panel)
Rank
Deterioration mode of parts
Rubber body: tears, permanent deformation, cracks (large), burns
Fixings: loose, bent, missing, cutaSupports: bent, cut
Fender panel: deformation
Resin pad: cut, missing, burnsb------Rubber body: tears (small), separation, ozone cracks
Fixings: corrodedcSupports: corroded
Fender panel: corroded
Resin pad: abrasion & weard
No deterioration

3) Pneumatic fenders
Table 3.1.3 Deterioration rank and mode of daily checks (Pneumatic fenders)
Rank
Deterioration mode of parts
Rubber body: cuts, wear (to fabric layer), burn, decreased air pressure
Fixings: loose, bent, missing, cutaAttachments: bent, cut
Fender panel: deformation
Resin pad: cut, missing, burnsb------Rubber body: tears (small), separation, ozone crack
airtightness malfunction
cFixings: corroded
Attachments: corrodeddNo deterioration

4) Cylindrical fenders
Table 3.1.4 Deterioration rank and mode of daily checks (Cylindrical fenders)
Rank
Deterioration mode of parts
Rubber body: drops, tears, burnsaSupports: bent, cutb------Rubber body: missing rubber, cracks, chipping, wear, ozoneccracksSupports: corrodeddNo deterioration

535) Other rubber equipment
Table 3.1.5 Deterioration rank and mode of daily checks (Other rubber equipment)
Rank
Deterioration mode of parts
Rubber body: drops, tear, permanent deformation, burnsa
Steps on rubber ladder: cuts
Fixings: loose, bent, missing, cutb------Rubber body: missing rubber, cracks, chipping, wear, ozone crackscFixings: corrodeddNo deterioration(2) Initial check and diagnosis, periodic check and diagnosis and occasional check and diagnosis
The determination methods of deterioration for the initial check and diagnosis, periodic check and diagnosis
and occasional check and diagnosis are shown in 3.2 to 3.6 for each fender type. For those checks anddiagnoses, the deterioration score is determined by measuring the damage rate of the rubber fenders.

3.2 V-type rubber fender
3.2.1 Method of check/diagnosis and functional evaluation for V-type rubber fender
In the initial check and diagnosis, periodic check and diagnosis, and occasional check and diagnosis of V-type rubber
fenders, a field survey is conducted, and the function is evaluated and recorded as follows. In the field survey of V-type
rubber fenders, the deterioration of each part is classified, a measurement of the damaged part is carried out for therubber body, and the deterioration rank is assessed for the fixings. Based on the results, for the rubber body, the damage
rate (%) is calculated from the breakage length or area, and the deterioration score is determined. The deterioration
rank of fixings is determined based on the condition of the parts. These results are entered on a checklist and saved as arecord. The procedure is shown below.
(1) Preparation of layout
Number the rubber fender to identify where in the facility the fenders to be checked are located and placethem on the overall floor plan of the facility. Specifically, see Appendix A: Fender Control Chart (Example).
(2) Preparation of the check sheet
Appendix B: Standard form of fender check and diagnosis may be used.
(3) Investigation
Perform an investigation of deterioration visually or using a scale. A picture or sketch is desirable.
(4) Classification of the deteriorated partThe deteriorated parts are classified into rubber bodies and accessories (fixings).
(5) Classification of the deterioration mode
Chapter 2, Section 2.2.2 Deterioration modes of V-type rubber fenders is taken as a reference.
(6) Calculation of the damage rate
Refer to Section 3.2.2 Damage rate. See Appendix C: Examples of determining deterioration score.

54

(7) Determining deterioration score and deterioration rank
Refer to Section 3.2.3 Deterioration score and ranks.
(8) Check sheet entry
Fill in the check sheet according to Section 3.2.4.
(9) Measures
Take measures based on Chapter 4.
The method of check/diagnosis and functional evaluation is shown in Fig. 3.2.1.

Fig. 3.2.1 Evaluation flow of check/diagnosis for V-type rubber fenders

3.2.2 Damage rate of V-type rubber fender by field survey
V-type rubber fenders are classified into straight bodies and circular bodies with V-shaped body sections. The
55

dimensions of the damaged part on the rubber body are measured, and the respective damage rates are calculated fromthe damaged length or damaged area. Additionally, with regard to the removed V-type rubber fenders, it is determined
whether re-installation is possible according to the state of bolt hole damage.
(1) Damage rate of V-type rubber fender
1) Length and area of damage
For tears, permanent deformation, cracks, and separation, the damage rate is calculated from the damage
length. The damage length is the sum of the projected lengths of damage to the longitudinal axis. This is
written as damage length {L1, L2,…}.
For drops, missing rubber, chipping, wear and burns, the damage rate is calculated from the damaged
area. The area of damage is the product of the length and width of the damaged part.
For calculation of damage length, the following matters are considered.
a. More than one damage point
As for L1 and L3 shown in Fig. 3.2.2, damages occurring in the same part are calculated only
when the projection length to longitudinal axis is longer (in the example, L3, L1 <L3). L1 isconsidered to be included in the L3 part.
b. Damage perpendicular to the longitudinal axis of rubber fenderIf cracking occurs in the direction perpendicular to the longitudinal axis of the rubber fender,
as shown in L4 in Fig. 3.2.2, it is not included in the calculation of damage length because it does
not affect the deformation of the rubber body.
c. Inclined damage
As shown in the L3 part shown in Fig. 3.2.3, if the damage is inclined, measure the projected
length (L6) to the longitudinal axis.
d. Combination of damages
・ If a crack is continuous with a tear, include it in the tear and use the length of damage.
・ If missing rubber is continuous to the drop, include the drop and use it as the area of damage.
・ When a tear and drop coexist, let each be the length of damage and the area of damage.
・ In the case of combinations other than the above, let each be the length of damage and thearea of damage.
e. Separation
・ Separation is taken as the total length of the damage generated on one side.
・ If there are separations on both sides, select the longer one for the total length.
2) Calculation of the damage rate
The damage rate is the ratio of damaged length to the length of the fender contacting face or the ratio of
damaged area to the fender contacting face.
a. Tears, Permanent deformation, Cracks and Burns

Damage rate (%)＝

Total damage length
Length of fender contacting face×100
(3.2.1)b. Separation

Damage rate (%)＝

Total separated length
Length of fixing flangec. Drops, Missing rubber, Chipping, Wear
56

×100
(3.2.2)

Damage rate (%)＝

Total damaged area
Area of fender contacing face×100
(3.2.3)

3) Example of damage rate calculation
Examples of damage rate calculations for drops, tears and separation are shown below.
a. Tears, Permanent deformation, Cracks and Burns
As shown in Fig. 3.2.2, when several damage types occur, measure the damage rate bymeasuring the length {L1, L2, L3, L4} of each crack. When it occurs in the same part as in the L1part and the L3 part, the longer L3 is taken. There is no damage length (L4) in the direction
perpendicular to the longitudinal axis. Therefore, L4 is ignored.

Damage rate (%) ＝｛L2＋L3｝×100
L(3.2.4)

As shown in Fig. 3.2.3, when the crack (L5) is oblique, the projection length (L6) to thelongitudinal axis is measured.

Damage rate (%) ＝

｛L6｝
×100
L

Fig. 3.2.2 Damage measurement(Longitudinal crack)(3.2.5)

Fig. 3.2.3 Damage measurement(Oblique crack)b. Drops, Missing rubber, Chipping, Wear
As shown in Fig. 3.2.4, if bulky damage occurs, measure the damage rate by measuring thelength {L7, L8} and width {W1, W2} of each damage type.

Damage rate (%)＝

｛L7×W1＋L8×W2｝
×100
L×W
57

(3.2.6)

Fig. 3.2.4 Damage measurement (Drops, Missing rubber, Chipping, Wear)c. Separation
As shown in Fig. 3.2.5 and Fig. 3.2.6, when rubber separation occurs in the fixing flange,measure the damage rate by measuring the length (L9, L10) of rubber separated from theembedded steel plate.

｛L 9＋L 10｝
×100
Damage rate (%)＝
Total length of fixing flange｛ΣL F}

Fig. 3.2.5 Damage measurement(Separation-Single flange)(2) Damage rate of circular rubber fender
1) Length and area of damage
58(3.2.7)

Fig. 3.2.6 Damage measurement(Separation-Multiple flange)

For tears, permanent deformation, cracks, and separation, the failure rate is calculated from the damage
length. The damage length is the sum of the lengths of damage. This is written as damage length { L1,
L2,…}.
For drops, missing rubber, chipping and wear, the damage rate is calculated from the damage area. The
area of damage is the product of the length and width of the damaged part.
For the calculation of damage length, the following matters are considered.
a. Multiple non-adjacent damages
If there are multiple non-adjacent damages, as shown in L1 and L2 in Fig. 3.2.7, then the total
length of damage is taken as the damage length.
b. Multiple adjacent damages
As shown in Fig. 3.2.7, when damages are adjacent as in L1 and L3, only the longer damage iscalculated, and it is considered that L3 is included in L1.
c. Combination of damages
・ If a tear is continuous with a crack, include it in the tear and use the length of the damaged area.
・ If a drop is continuous to missing rubber, include the drop and use it as the area of damage.
・ When a tear and a drop coexist, let each be the length and the area of the damage.
・ In the case of combinations other than the above, let each be the length and the area of damage.

Fig. 3.2.7 Damage measurement(tears, permanent deformation, cracks, separation and burns - Circular fender)
2) Calculation of the damage rate
The damage rate is indicated by the ratio of the diameter of the fender contacting the face to the lengthof damage or by the ratio of the area of the fender contacting the face and damaged area.
a. Tears, Permanent deformation, Cracks, Separation and Burns

Damage length ｛L 1＋L 2＋・・・｝
×100
Damage rate (%)＝
Diametet of fender contacting face{L}(3.2.8)b. Drops, Missing rubber, Chipping, Wear

Damage rate (%)＝

Total damaged area
Area of fender contacing face

59

×100
(3.2.9)3) Example of damage rate calculations
Examples of damage rate calculations are shown below.
a. Tears, Permanent deformation, Cracks, Separation and Burns
As shown in Fig. 3.2.7, when several damage types occur, measure the damage rate bymeasuring the length {L1, L2, L3} of each crack. When it occurs in the same part as in the L1 part andthe L3 part, the longer L1 is taken.

Damage rate (%) ＝｛L1＋L2｝×100
L(3.2.10)b. Drops, Missing rubber, Chipping and Wear
As shown in Fig. 3.2.8, if bulky damage occurs, measure the damage rate by measuring the length{L4, L6} and width {L5, L7} of each damage type.
Damage rate (%) ＝｛L4×L5＋L6×L7｝
×100(π×L2/4)(3.2.11)

Fig. 3.2.8 Damage measurement(Drops, Missing rubber, Chipping and Wear - Circular fender)(3) Re-installing removed rubber fender
If damage has occurred to the rubber fender fixing holes (holes through which the fixing bolt passes
through the fixing flange), determine whether re-installation is possible based on Table 3.2.1. Re-installation is
not recommended when damage occurs in one or more places. When making this judgement, you may refer to
Photo 3.2.1 and Photo 3.2.2.

60

Table 3.2.1 Judgement of bolt hole damage (V-type rubber fender)
Judgement
Bolt hole condition
Severe corrosion occurs in the entire hole accompanied by aRe-installation
not recommended reduction in plate thickness (hole deformation).
Re-installable

There is no corrosion or deformation in the fixing hole,or corrosion is observed but is partial.

Photo 3.2.1 Re-installation not recommended (Example)

If the coated rubber is peeled off and the iron plate is exposed but there is no decreasein thickness, the failure rate is calculated as separation.
Photo 3.2.2 Re-installable (Example)

3.2.3 Functional evaluation
The functional evaluation of a V-type rubber fender is divided into the functional deterioration of the rubber bodyand the deterioration rank of the accessories. The score of functional deterioration of the rubber body iscomprehensively judged considering the age of the fenders, the structure type of the quay, and the usage condition of
the ship. The degree of deterioration of accessories is determined to be the deterioration ranking.
Rubber body:
The score of functional deterioration of the rubber body is determined by dividing the damage rate into six stages
and calculating the deterioration score that is obtained by adding the score shown for each deterioration mode anddamage rate.
Accessories:
The deterioration rank of accessories (fixings) is determined by dividing the visual condition of the part/member into
four stages.

61(1) Deterioration score of rubber body1) Method to score the deterioration
For the deterioration score of the rubber body, the score shown in Table 3.2.2 is added by eachdeterioration mode and damage rate. When there are two or more deterioration modes among (1) to (11),only the two larger scores are added, and the maximum ceiling is 12 points.
Table 3.2.2 Deterioration score table of rubber body (V-type rubber fenders)Damage rate
40% or30~39%
20~29%
10~19%
1~9%
Deterioration mode
more
(1) Drop (Area)
6
6
6
4
2
(2) Tear (Length)
6
6
6
4
2
(3) Permanent
6
6
6
4
2
deformation (Length)(4) Missing rubber (Area)
3
2
1
0
0
(5) Crack (Length)
3
2
1
0
0
(6) Chipping (Area)
3
2
1
0
0
(7) Separation (Length)
3
2
1
0
0
(8) Wear (Area)
1
1
1
0
0
(9) Burn (Length)
6
6
6
4
2
(10)

Bolt hole damage(11)

Ozone crack

Re-installation not recommended6
Age 20 years or more
1

0%
0
0
0
0
0
0
0
0
0

Re-installable
0
Age less than 20 years
02) Functional evaluation
The functional evaluation of the rubber body is based on the deterioration score based on Table 3.2.3.
Table 3.2.3

Functional evaluation of rubber body (V-type rubber fenders)(Initial, Periodic and Occasional check/diagnosis)

Deterioration score

Functional evaluation

6 points or more

Significant functional deterioration

3~5 points

Functional deterioration started

1~2 points

Function will deteriorate if left unchecked

0 points

No functional deterioration

For measures, see Table 4.2.1 in 4.2.1 Measures for rubber body.
(2) Deterioration rank of accessories (fixings)
The deterioration rank of fixings is judged based on the condition of parts and members based on Table
3.2.4.
Table 3.2.4 Function evaluation of fixings (V-type rubber fender)(Initial, Periodic and Occasional check/diagnosis)
Deterioration rank
Condition of part and memberaLoose, Bent, Missing and/or Cutb－－－cCorrosion observedd
No deterioration
For measures, see Table 4.2.2 in 4.2.2 Measures for accessories.

623.2.4 Check sheet and record
Regarding the deterioration that has occurred in the rubber body and accessories, record the state of deterioration foreach V-type rubber fender on the check sheet. Fig. 3.2.9 shows an example of a check sheet prepared for the case of
Photo C.10 in Appendix C: Evaluation of Functional Deterioration.

Check sheet of V-type rubber fender
Location
Name of port
Fender size

Date ofinstallation
Name of quay
Fender ID○○ County○○ Port○○ 400 H×1500 L

1. Rubber body○/ ○ / ○-5.0 mNo.1

Wharf No. ○○2. Accessories (fixings)○ / ○ / ○John F. Kowan
Inspection result

Date of inspection
Inspector
Items

Items

Inspection result(D e t . M o d e )
(1)

Drop

(2)

Tear

(3)

Permnt. Deform.

(4)

Missing rubber

(5)

Crack

(6)

Chipping(7)

Separation

(8)

Wear

(9)

Burn

Det.
mode

Length orarea ofdamageDamage
rate

Det.
score

(4)

1750 cm2

47%

3

(7)

80 cm

53%

3

(1)

Loose

(2)

Bent

(3)

Missing

(4)

Cut

(5)

Corrodeda (One bolt missing)(10) Bolt hole damage

Total(11) Ozone crack

Deterioration score

Bolt replacement

6

Considerations whena) Age 20 years or moredeterioration score is3~5. If checked,b) Mooring 10,000 hours or more
replacement isc) Load sensitive quay structure
recommended.
Measure for rubber
body

6

□
□

Measure foraccessories□

Replacement
No

Yes(Date of completion:

)

No

Yes

(Date of completion:

3. Background information (Photo, sketch, calculation)
Missing rubber:→Deterioration score 3 points

Photo or sketch ofdamageSeparation:

Process offunctional
evaluation→Deterioration score 3 points

Fig. 3.2.9 Example of check sheet (V-type rubber fender)63)

3.3 Rubber fender with fender panel
3.3.1 Method of check/diagnosis and functional evaluation for rubber fender with panel
In the initial check and diagnosis, periodic check and diagnosis, and occasional check and diagnosis of rubber
fenders with a panel, a field survey is conducted, and the function is evaluated and recorded. The details of the checkand diagnosis and functional evaluation procedures conform to 3.2 V-type rubber fenders. The flow of check/diagnosis
and functional evaluation is shown in Fig. 3.3.1.

Fig. 3.3.1 Evaluation flow of check/diagnosis for rubber fender with fender panel

3.3.2 Damage rate by field survey for fender with panel
Rubber fenders with panels can be sorted into longitudinal types and circular types according to the shape of therubber body. The dimensions of the damaged part generated in the rubber body are measured, and the damage rate is
calculated from the damaged length. In addition, with regard to a removed rubber fender and panel, it is determined
whether it can be re-installed based on the state of the bolt holes.

64(1) Damage rate of longitudinal rubber fender with panel
1) Length of damage
For tears, permanent deformation, cracks, separation and burns, the damage rate is calculated from thedamage length. The damage length is the sum of the lengths of damaged parts, which is written as {L1,
L2…}.
The calculation of the damage length is performed in consideration of the following matters.
a. The rubber body is a group of modules (A and B legs)
As shown in Fig. 3.3.2, when the rubber body is divided into one pair (A and B legs), each leg isevaluated.
b. Plural damage
As shown in the A leg of Fig. 3.3.2, when there are multiple damage types, the total projected
lengths of the damages will be the damage length.
c. Single damage on both sides of the body
As shown in the B leg of Fig. 3.3.2, for the cracks occurring in the same part, only the projection
length to longitudinal axis is calculated, so the L5 part is included in the L4 part.
d. Combination of damages
If a crack is continuous with a tear, include it in the tear to calculate the damaged length.

A leg
B leg
Note: These leg sides are expanded to show both sides
Fig. 3.3.2 Damage measurement (longitudinal shape with panel)

2) Calculation of the damage rate
The damage rate is indicated by the ratio of the damage length to the length of the rubber body.

Damage rate (%)＝

Damage length ｛L 1 +L 2＋・・・｝
Length of rubber body {L}×100(3.3.1)

3) Example of damage rate calculation
Cracks and tears are shown as representative calculation examples of the damage rate.
a. Cracks, Permanent deformation, Separation
As shown in Fig. 3.3.2 (A leg), when several cracks are generated, calculate the damage rate bymeasuring the length {L1, L2, L3} of each crack.
65Damage rate (%) ＝｛L1＋L2＋L3｝
×100
L(3.3.2)b. Tears
As shown in Fig. 3.3.2 (B leg), if tears are occurring, calculate the damage rate by measuring thelength {L4, L5} of each damage. If it occurs in the same part as in the L4 part and the L5 part, thelonger L4 is taken.
L4
Damage rate (%) ＝ L ×100

(3.3.3)(2) Damage rate of circular rubber fender with panel
1) Length of damage
For tears, permanent deformation, cracks, separation and burns, the damage rate is calculated from thedamage length. The damage length is the sum of the lengths of damaged parts, which is written as {L1,
L2…}. The calculation of the damage length is performed in consideration of the following matters.
a. Multiple remote damages
As shown in L1, L3 and L4 in Fig. 3.3.3, when there are multiple damages, the total projected
lengths of the damages will be the damage length.
b. Multiple adjacent damages
If the damage consists of multiple cracks adjacent to each other, as shown in L1 and L2 in Fig.
3.3.3, only the larger crack is taken as the length of damage cracks.
c. Combination of damages
If a crack is continuous with a tear, include it in the tear to calculate the damage length.

Fig. 3.3.3 Damage measurement (Circular shape with panel)

2) Calculation of the damage rate
The damage rate is indicated by the ratio of the damage length to the length of the rubber body.

Damage rate (%)＝

Damage length ｛L 1 +L 2＋・・・｝
Length of rubber body {L}3) Example of damage rate calculation
66

×100(3.3.4)

Cracks and tears are shown as representative calculation examples of the damage rate. As shown in Fig.
3.3.3, if damage occurs, the damage rate is calculated by measuring the length { L1, L2, L3, L4} of eachdamage. If damage occurs in the adjacent group as in the L1 part and the L2 part, the longer L1 is taken.

Damage rate (%)＝

｛L 1 +L 3＋L 4｝
L

×100(3.3.5)(3) Re-installing removed rubber fender
If damage has occurred to the rubber fender fixing holes (holes through which the fixing bolt passes
through the fixing flange), determine whether re-installation is possible based on Table 3.2.1. Re-installation is
not recommended when damage occurs in one or more places. When making this judgement, you may refer to
Photo 3.2.1 and Photo 3.2.2.

3.3.3 Functional evaluation of rubber fender with panel
The functional evaluation of a rubber fender with panel is divided into the functional deterioration of the rubber
body and the deterioration rank of the accessories. The score of functional deterioration of the rubber body iscomprehensively judged in consideration of the age of the fenders, the structure type of the quay, and the usage
condition of the ship. The degree of deterioration of the accessories is determined as the deterioration ranking.
Rubber body:
The score of functional deterioration of the rubber body is determined by dividing the damage rate into six stages
and calculating the deterioration score that is obtained by adding the score shown for each deterioration mode anddamage rate.
Accessories:
The deterioration rank of accessories (fender panel, fixings, supports, resin pad) is determined by dividing the visualcondition of the part/member into four stages.
(1) Deterioration score of rubber body1) Method to score the deterioration
For the deterioration score of the rubber body, the score shown in Table 3.3.1 is added by eachdeterioration mode and damage rate. When there are two or more deterioration modes among (1) to (7),only the two larger scores are added, and the maximum ceiling is 12 points.
Table 3.3.1 Deterioration score table of rubber body (Rubber fender with panel)
Damage rate
40% or30~39%
20~29%
10~19%
1~9%
Deterioration mode
more(1) Crack (Length)
6
4
4
3
1
(2) Tear (Length)
6
6
6
4
2
(3) Permanent
6
6
6
4
2
deformation (Length)(4) Separation (Length)
3
2
1
0
0
(5) Burn (Length)
6
6
6
4
2
(6)

Bolt hole damage(7)

Ozone crack

Re-installation not recommended6
Age 20 years or more
167

Re-installable
0
Age less than 20 years
0

0%
0
0
0
0
0

2) Functional evaluation
The functional evaluation of the rubber body is based on the deterioration score based on Table 3.3.2.
Table 3.3.3 Functional evaluation of rubber body (Rubber fender with panel)(Initial, Periodic and Occasional check/diagnosis)
Deterioration score

Functional evaluation

6 points or more

Significant functional deterioration

3~5 points

Functional deterioration started

1~2 points

Function will deteriorate if left unchecked

0 points

No functional deterioration

For measures, see Table 4.2.1 in 4.2.1 Measures for rubber body.
(2) Deterioration rank of accessories (fender panel, fixings, supports, resin pad)1) Fender panel
The deterioration rank of the fender panel is judged based on the condition of part and member based on
Table 3.3.3. When making this judgement, you may refer to Photo 3.3.1 and Photo 3.3.2.
Table 3.3.3 Functional evaluation of fender panel (Rubber fender with panel)(Periodic and Occasional check/diagnosis)
Deterioration rank
Condition of part and memberaThe deformation is too large for further use.
Widespread severe corrosion accompanied by adecrease in steel plate thickness. (See Photo 3.3.1)b－－－cMiner deformation but can be used continuously.
Corrosion is observed but partial. (See Photo 3.3.2)
d
No deformation. No paint deterioration and almost
no corrosion.
For measures, see Table 4.2.2 in 4.2.2 Measures for accessories.

Photo 3.3.1 Example of damage rank “a” of fender panel corrosion

68

Photo 3.3.2 Example of damage rank “c” of fender panel corrosion
2) Fixings
The deterioration rank of fixings is judged based on the condition of the part and member based on Table
3.3.4. When making this judgement, you may refer to Appendix D: Example of deterioration rank for
fixings.
Table 3.3.4 Functional evaluation of fixings (Rubber fender with panel)(Initial, Periodic and Occasional check/diagnosis)
Deterioration rank
Condition of part and memberaLoose, Bent, Missing and/or Cutb－－－cCorrosion observedd
No deterioration
For measures, see Table 4.2.2 in 4.2.2 Measures for accessories.
3) Supports
The deterioration rank of supports is judged based on the condition of the part and member based on Table
3.3.5.
Table 3.3.5 Functional evaluation of supports (Rubber fender with panel)(Initial, Periodic and Occasional check/diagnosis)
Deterioration rank
Condition of part and memberaSignificant bends, cuts or corrosion; further use is
impossibleb－－－cBent and corroded, but further use possibled
No deterioration
For measures, see Table 4.2.2 in 4.2.2 Measures for accessories.
4) Resin pad
The deterioration rank of the resin pad is judged based on the condition of the part and member based on
Table 3.3.6. When making this judgement, you may refer to Photo 2.3.17 to Photo 2.3.20.

69

Table 3.3.6 Functional evaluation of resin pad (Rubber fender with panel)(Initial, Periodic and Occasional check/diagnosis)
Deterioration rank
Condition of part and memberaCut, missing and/or burned. Severe abrasion andwear reaching to the bolt head.
b－－－cMinor abrasion or wear was observed, but further
use is possible.
d
No deterioration
For measures, see Table 4.2.2 in 4.2.3 Measures for accessories.

3.3.4 Check sheet and record
Regarding the deterioration that has occurred in the rubber body and accessories, record the state of deterioration foreach rubber fender with panel on the check sheet. Fig. 3.3.4 shows an example of the check sheet.

70Check sheet of Rubber fender with Panel
Date ofinstallation
Name of quay
Fender ID○○ County

Location○○ Port○○1000 H×1500 L

Name of port
Fender size

1. Rubber body○/ ○ / ○-10.0 mNo.7

Wharf No. ○○2. Fender panel○ / ○ / ○Donald J. Port
Inspection result

Date of inspection
Inspector
Items

Items

Inspection result〔Det. mode〕
(1)

Tear

(2)

Crack

(3)

Permnt. Deform.

(4)

Separation

(5)

Burn

(6)

Bolt hole damage(7)

Ozone crack

Det.
mode

Length orarea ofdamage(1)(2)

Damage
rate

Det.
score

20 cm

13%

3

80 cm

53%

6

Total

9

Deterioration scorea Severe and widespread corrosion□□

Measurement for
fender panel□
Replacement

Replacement

No

Yes

）

(Date of completion:

3. Fixings

No

4. Supports

Items

Inspection result

Inspection resulta (One shackle bend)Loosec (One nut loose)

(1)

Bent

(2)

Bent

a (One bolt missing)

(2)

Cut

(3)

Missing(3)

Corroded

(4)

Cut

(5)

CorrodedRe-tighten nut
Yes (Date of comp.

)）(Date of completion:a (Severe chain corrosion)

Items

Inspection result

(1)

Wear

c (Wear on whole surface)(2)

Abrasion

(3)

Cut

(4)

Missing

Replacement

Replacement for missed bolt
No

Yes

5. Resin pad

Items

(1)

Measurec (Partial bending of steel plate)(2) Corroded

9

Considerations when a) Age 20 years or moredeterioration score is3~5. If checked,b) Mooring 10,000 hours or more
replacement isc) Load sensitive quay structure
recommended.
Measure for rubber
body(1) Deformation

Measurea (2 pads missing)
Replacement of missed pad

MeasureNo

Yes (Date of comp. )No Yes (Date of comp.

6．Background information (Photo, sketch, calculation)
・Damage rate of tear＝20/150×100＝13%→Deterioration score: 3
・Damage rate of crack＝80/150×100＝53%→Deterioration score: 6

Photo or sketch ofdamageProcess offunctional
evaluation

Fig. 3.3.4 Example of check sheet (Rubber fender with panel)71)3.4 Pneumatic fender
3.4.1 Method of check/diagnosis and functional evaluation for pneumatic fender
In the initial check and diagnosis, periodic check and diagnosis and occasional check and diagnosis of pneumatic
fenders, a field survey is conducted, and function is evaluated and recorded. Since the pneumatic fender absorbs theberthing energy of a ship using the elasticity of air filled in a rubber body, the deterioration level and airtightness of therubber body are important.
(1) Preparation of the whole layout
To clarify which position in the facility the pneumatic fender to be checked is located, write the number ofthe pneumatic fender on the overall facility plan. See Appendix A: Fender Maintenance Chart (Example).
(2) Preparation of fender check sheet
Appendix B: Standard form of fender check and diagnosis may be used.
(3) Investigation
Perform visually or use a scale and/or pressure gauge. A picture or sketch is desirable.
(4) Classification of deteriorated parts
Classify the deteriorated parts into the rubber body, air inlet valve, body attachment, and floating attachment(net, mooring bracket) or fixed type attachment with panel (fender panel, fixings, supports, resin pad).
(5) Classification of deterioration mode
Refer to Section 2.4.2 in Chapter 2 Deterioration modes of pneumatic fender.
(6) Measurement and calculation of air pressure (internal pressure) and temperature
Conduct based on 3.4.2 Deterioration level and degree of airtightness maintenance.
(7) Judgement of deterioration level and airtightness
Judge based on 3.4.2 deterioration level and air tightness.
(8) Judgement of functional deterioration and deterioration rank
Judge based on 3.4.3 Functional evaluation.
(9) Check sheet entry
Refer to 3.4.4 Checklist entry.
(10) Measures
Take measures based on Chapter 4.
The flow of check and diagnosis and functional evaluation is shown in Fig. 3.4.1.

72

Fig. 3.4.1 Evaluation flow of check/diagnosis for pneumatic fender

3.4.2 Deterioration level and degree of airtightness maintenanceThe determination of the deterioration score of the pneumatic fender is performed based on the deterioration level
and the degree of airtightness maintenance.
(1) Deterioration level of pneumatic fender body
The deterioration level due to cracks, chipping, wear, ozone cracks, separation, cuts and burns generated in
the rubber body of the pneumatic fender is determined by classifying the state of deterioration into six stages
based on Table 3.4.1. If damage has occurred to the fixing hole (hole for anchor bolts to fixing flange) of thepneumatic fender, determine the possibility of re-installation based on Table 3.2.1. Re-installation is
impossible when damage occurs in one or more places. In addition, in the case of determination, you may referto photo 3.2.1 and photo 3.2.2.

73

Table 3.4.1 Deterioration level of pneumatic fender
Deterioration
level

Deteriorationlevel I

Deteriorationlevel II

Deteriorationlevel III
Deteriorationlevel IV
Deteriorationlevel V
Deteriorationlevel VI

Condition of parts and member
There are damages or burns in the outer layer, reinforcing layer, and inner layer.
The corrosion of the embedded steel plate progresses significantly, separation
progresses to the inside of the rubber along the embedded steel plate, anddamage such as cut occurs in the inner layer.
Not recommended to be re-installed due to bolt hole damage (fixed type).
Inner layer rubber has no damages or burns, but reinforcing layer is partiallycracked, separated or worn away.
There is no air leakage, but embedded steel plate is exposed and corrosion
progresses inside rubber.
Outer layer rubber is cracked, chipped, separated, worn away or burned, and thereinforcing layer is exposed.
There is no air leakage, but the surface rubber covering the embedded steel plateis peeled off, and the embedded steel plate is exposed.
Outer layer rubber is cracked, chipped, separated, worn away or burned(reinforcing layer is not exposed).
Ozone cracks have occurred in outer rubber layer.
No damage to rubber body.
No separation of embedded steel plate.

(2) Airtightness of pneumatic fenders
When determining the airtightness of the pneumatic fender, the internal pressure and temperature measured
at the time are compared with the internal pressure and temperature measured at a previous time. Converted
internal pressure is calculated using equation 3.4.1.

Pt＝(101.3＋P0)×

273＋tt－101.3273＋t0(3.4.1)

Pt : Current converted internal pressure (kPa)P0 : Previous internal pressure (kPa)tt : Current temperature at pressure measurement (°C)
t0 : Previous temperature at pressure measurement (°C)
The airtightness of pneumatic fenders is determined by dividing the state of converted internal pressure into
four levels based on Table 3.4.2.
Table 3.4.2 Degree of airtightness maintenanceAirtightness
Condition of converted inner pressure
Airtight I
Measured air pressure is zero, and air cannot be filled.
Airtight II
Previous setting (or measured) internal pressure exceeds ± 10 kPa.
Airtight III
Within ±10 kPa of previous setting (or measured) internal pressure
Airtight IV
Same as the previously set (or measured) internal pressure.
Note 1) For Airtight II, as a retest, air is filled to the specified internal pressure and left for 24 hours, andthen the internal pressure is measured (including the ambient temperature) again. If theconverted internal pressure is within ± 5 kPa, it is judged as Airtight III.
Note 2) To compare the measured internal pressure of the pneumatic fender with the specified internal74

pressure, calculate the internal measured pressure converted to the temperature at the specified
internal pressure using the ambient temperature measured simultaneously. In principle, theinternal pressure is set at a Japanese average temperature of 15 °C. However, depending on theusage of the pneumatic fender, it is also possible to set a pre-set temperature for each region oreach season.
(3) Check method of air pressure
An example of the measurement method and charging method of the air pressure of a pneumatic fender is
be shown below. For details, check the instruction manual of each manufacturer.
1) Floating pneumatic fendera. Check of air pressure
· Remove the cap ② of the air inlet valve ①.
· Press the air chuck ④ of the pressure gauge ③ against the air inlet valve ① to measure theair pressure.
b. Charging method of air (mid-small size smaller than Φ2000)
· Remove the cap ② of the air inlet valve ①.
• Connect the air-charge device to the compressor.
· Press the air chuck ④ against the air inlet valve ① to fill it with air.
・According to a above, fill up to the target internal pressure while measuring the air pressure.
c. Charging method of air (large size φ2000 or larger)
· Connect the air charge joint ⑤ to the fender. (connection location and method differ dependingon the manufacturer)• Connect the air charging device to the compressor.
• Fill to the target internal pressure while measuring the air pressure by opening and closing thevalve of the pressure gauge ⑥.

Fig. 3.4.2 Pressure measuring and air charge method (Floating type)Note) Check and observe the specified internal pressure when measuring or filling air pressure. In addition,
when filling with air, be sure to check with a pressure gauge to prevent introducing too much air.
752) Fixed type pneumatic fender with panela. Check of air pressure
· Loosen the bolt ⑧ slightly with spanner ⑨ and open the valve protector ⑦.
· Remove the cap ② on the air inlet valve ①.
· Press the air chuck ④ of the pressure gauge ③ against the air inlet valve ① to measure the airpressure.
b. Charging method of air
· Remove the cap ② of the air inlet valve ①.
• Connect the air charge device to the compressor.
· Press the air chuck ④ against the air inlet valve ① to fill it with air.
· According to a above, fill up to the target internal pressure while measuring the air pressure.

Fig. 3.4.3 Pressure measuring and air charge method (Fixed type with panel)Note) Check and observe the specified internal pressure when measuring or filling air pressure. In
addition, when filling with air, be sure to check with a pressure gauge to prevent introducing
too much air.

3.4.3 Functional evaluation for pneumatic fender
The functional evaluation of pneumatic fenders is judged comprehensively from the age of the fenders, structural
type of quay, usage of ships, and degree of deterioration of accessories in addition to functional deterioration for therubber body.
Deterioration score:
The functional deterioration of the rubber body is determined by dividing the deterioration into six levels, theairtightness maintenance level into four levels and adding the score indicated for each deterioration and airtightness76

level.
Deterioration rank:
The degree of deterioration of accessories includes air inlet valve, body attachment, floating type attachment (net,mooring parts), and fixed type with fender panel (panel section, fixings, supports, resin pad). Divide the state of partsand members into 4 levels and evaluate.
(1) Deterioration score of the rubber body1) How to obtain the deterioration score
The deterioration score of the rubber body is calculated by adding the points shown in Table 3.4.3
based on deterioration level and the degree of airtight maintenance.

Deterioration
score

Table 3.4.3 Deterioration score of rubber body (Pneumatic fender)
Deterioration level/Degree of
I
II
III
IV
V
airtightness maintenanceVI(1) Deterioration level

6

5

4

2

1

0

(2) Degree of airtightness
maintenance

6

4

1

0

-

-

2) Functional evaluation
Functional evaluation is based on the deterioration score based on Table 3.4.4.
Table 3.4.4 Functional evaluation of rubber body (Pneumatic fender)(Initial, Periodic and Occasional check/diagnosis)
Deterioration score

Functional evaluation

6 points or more

Significant functional deterioration

3~5 points

Functional deterioration started

1~2 points

Function will deteriorate if left unchecked

0 points

No functional deterioration

For measures, see Table 4.2.1 in 4.2.1 Measures for rubber body.
(2) Deterioration rank of accessories
1) Air inlet valve
The deterioration rank of the air inlet valve is based on the condition of parts and members in Table 3.4.5.
Table 3.4.5 Deterioration rank of air inlet valve (Pneumatic fender)(Initial, Periodic and Occasional check/diagnosis)
Deterioration rank
Condition of parts and member
There is damage. The progress of corrosion is extensive andathe valve cannot be used continuously, or there is air leak.
b－－－cThere is corrosion, but continued use is possibled
No deterioration
For measures, see Table 4.2.2 in 4.2.2 Measures for accessories.
2) Body attachment
The deterioration rank of the body attachment is evaluated based on Table 3.4.6 based on the77condition of parts and members.
Table 3.4.6 Deterioration rank of body attachment (Pneumatic fender)(Initial, Periodic and Occasional check/diagnosis)
Deterioration rank
Condition of parts and member
There is damage. The progress of corrosion is extensive,aand the attachment cannot be used continuously.
b－－－cThere is corrosion, but continued use is possibled
No deterioration
For measures, see Table 4.2.2 in 4.2.2 Measures for accessories.
3) Floating type attachment
a. Nets
The deterioration rank of a net is judged based on the condition of the parts and members based on
Table 3.4.7.
Table 3.4.7 Deterioration rank of net (Pneumatic fender)(Initial, Periodic and Occasional check/diagnosis)
Deterioration rank
Condition of parts and member
There is a disconnection of the net, or the progress ofcorrosion is extensive, and it cannot be used
continuously.
a
The old tyre or rubber sleeve have significant burns andhave lost function as a protective member of the fender
body.
b
－－－
c
There are cuts, wear and/or corrosion, but continued use
is possible.
d
No deterioration
For measures, see Table 4.2.3 in 4.2.2 Measures for accessories.
b. Mooring parts
The deterioration rank of mooring parts is judged based on the condition of the part and member
based on Table 3.4.8.
Table 3.4.8 Deterioration rank of mooring parts (Pneumatic fender)(Initial, Periodic and Occasional check/diagnosis)
Deterioration rank
Condition of parts and memberaThere is bending, cutting or progressed corrosion, and theparts cannot be used continuously.
－－－
There is bending and corrosion, but continued use ispossible.
d
No deterioration
For measures, see Table 4.2.2 in 4.2.2 Measures for accessories.
bc4) Accessories for fixed type fender with panel
a. Fender panel
The deterioration rank of the fender panel is judged based on the condition of the part and member
78based on Table 3.4.9.
Table 3.4.9 Functional evaluation of fender panel (Pneumatic fender with panel)(Initial, Periodic and Occasional check/diagnosis)
Deterioration rank
Condition of part and member
The deformation is too large for further use.
a
Widespread severe corrosion accompanied by adecrease in steel plate thickness. (See Photo 3.3.1)
b－－－Minor deformation but can be used continuously.
cCorrosion is observed but partial. (See Photo 3.3.2)
No deformation. No paint deterioration and almostdno corrosion.
For measures, see Table 4.2.2 in 4.2.2 Measures for accessories.
b. Fixings
The deterioration rank of fixings is judged based on the condition of the part and member basedon Table 3.4.10.
Table 3.4.10 Functional evaluation of fixings (pneumatic fender with panel)(Initial, Periodic and Occasional check/diagnosis)
Deterioration rank
Condition of part and memberaLoose, bent, missing and/or cut fixings were foundb－－－cCorrosion observedd
No deterioration
For measures, see Table 4.2.2 in 4.2.2 Measures for accessories.
c. Supports
The deterioration rank of supports is judged based on the condition of the part and member basedon Table 3.4.11.
Table 3.4.11 Functional evaluation of supports (Pneumatic fender with panel)(Initial, Periodic and Occasional check/diagnosis)
Deterioration rank
Condition of part and memberaSignificant bends, cuts or corrosion making further
use impossibleb－－－cBends and corrosion, but further use is possibled
No deterioration
d. Resin pad
The deterioration rank of the resin pad is judged based on the condition of the part and member
based on Table 3.4.12. When making this judgement, you may refer to Photo 2.3.17 to Photo 2.3.20.

79

Table 3.4.12 Functional evaluation of resin pad (Pneumatic fender with panel)(Initial, Periodic and Occasional check/diagnosis)
Deterioration rank
Condition of part and memberaCut, missing or burned pads were found. Severe
abrasion and wear reaching to the bolt head.
b－－－cMinor abrasion or wear was observed, but further
us is possible.
d
No deterioration
For measures, see Table 4.2.2 in 4.2.3 Measures for accessories.

3.4.4 Check sheet and record
Regarding the deterioration that has occurred in the pneumatic fenders and the deterioration that has occurred in eachmember, the deterioration status is recorded on a check sheet for each pneumatic fender. At the same time, measure andrecord the air pressure inside the fender. Fig. 3.4.4 and Fig. 3.4.5 show examples of the check sheet.

80Check sheet of Pneumatic fender
Location
Name of port
Fender size○○ County○○ PortPneumaticφ2500×5000 L-40 kPa

Date of installation
Name of quay
Fender ID○/ ○ / ○-5 m Wharf No. ○○No. ○2. Air inlet valve

3. Body attachment

1. Rubber body○ / ○ / ○Date of inspection
Inspector
Items

Inspection result

Items

Inspection result[Deterioration mode]
Det. mode

Level

Condition

Degree ofAirtightness

Airtight

III

Det. levelIVmaintenance
Deterioration levelWithin±10 kPa
Crack onouter layer

Det.
score

Air inlet valvea Deformation of valve

3(1)

Damage(2)

Corroded

2

Total
3
Previous pressure 40 kPa (Temp. 15 ℃) Body attachment
Measured pressure 35 kPa (Temp. 10 ℃) (1) Damage
Converted pressure 37.5 kPac.

Corrosion around nozzle(2) Corroded

Deterioration score
Considerations
when deterioration
score is 3~5. Ifchecked,replacement isrecommended.
Measure for rubber
body3a) Age 20 years or more□b) Mooring 10,000 hours or more□c) Load sensitive quay structure□

Replacement

No

Yes

）

(Date of completion:

Measurement

Replacement

No

Yes

(Date of completion:）

4. Net5. Mooring parts
Items

Inspection result

Items

(1)

Corrosiona (Remarkable corrosion)

(1)

Bends

(2)

Cuts

a (Cut of chain net)

(2)

Cuts

(3)

Cracks(3)

Corroded

(4)

Wear

MeasureInspection resulta (Severe corrosion)

ReplacementNo

Yes (Date of comp.

Measure)ReplacementNo

Yes (Date of comp. )6. Background information (Photo, sketch, calculation)
Deterioration level

Deterioration

score
劣化

Level IV： Crack at outer layer

2 points

Airtight III： Within ±10 kPa of previous pressure 1 point
Pressure conversion

Photo or sketch ofdamage＝ (101.3+40)×(273+10)/(273+15)－101.3

Process offunctional
evaluation＝ 37.5
Airtight III ((From previous pressure,
2.5 kPa (＝ 40－37.5))

Total: 3 points

Fig. 3.4.4 Example of check sheet (Pneumatic fender)81

Check sheet of Fixed type Pneumatic fender with Panel○○ County○○ PortPneumaticφ1200×1200H-120 kPa

Location
Name of port
Fender size

Date of installation
Name of quay
Fender ID○/ ○ / ○-10 m Wharf No. ○○No. ○2. Air inlet valve

3. Body attachment

1. Rubber bodyInspection result[Deterioration mode]
Det.mode
Degree ofAirtightness
maintenance

Condition

Level

Airtight

III

Det. level

IV

Items

Inspection result

Air inlet valve

Det.
score

(1) Damagea Deformation of valve(2) Corroded

Within±10 kPa
Crack onouter layer

Deterioration level1
Body attachment(1) Damage(2) Corroded

2
3

Total

T

Previous pressure 120 kPa(Temp. Fender panel
15 ℃)(1) Deformation
Measured pressure 115 kPa (Temp. 10 ℃) (2) Corroded
Converted pressure 116.2 kPa
Deterioration score

No

Yes

□
）

No

(2)

Bent

a (One bolt missing)

(2)

Cuts

(3)

Corroded

Yes）(Date of completion:

7. Resin pada (One shackle bend)

Bends

(5)

Measurement

Inspection result

(1)

Cut

Replace fender panel

□

Items

c (One nut loose)(4)

Replace air inlet valve

6. Supports
Inspection result

Loose
Missinga Severe and widespread corrosion☑

(Date of completion:

(1)
(3)

c Partial bending of steel plate

Replacement

5. Fixings
Items

c. Damage at valve protector

3

Considerations when a) Age 20 years or moredeterioration score is3~5. If checked,b) Mooring 10,000 hours or more
replacement isc) Load sensitive quay structure
recommended.
Measure for rubber
body

4. Fender panel○ / ○ / ○Date of inspection
Inspector
Items

Items

Inspection result(1) Wear/Abrasionc Wear on whole surface(2) Cuta (Severe chain corrosion) (3) Missing

a 2 pads missing(4) Burn

CorrodedRe-tighten nut

MeasureReplacement

Replacement for missed boltNo

Yes (Date of comp.

)

MeasureNo

Replacement of missed

MeasureYes (Date of comp. )pad
No Yes (Date of comp.

8. Background information (Photo, sketch, calculation)
Deterioration level

Deterioration

score
劣化

Photo or sketch ofdamageLevel IV： Crack at outer layer

2 points

Airtight III： Within ±10 kPa of previous pressure 1 point
Pressure conversion

Process offunctional
evaluation＝ (101.3+120)×(273+10)/(273+15)－101.3＝ 116.2
Airtight III ((From previous pressure,
3.8 kPa (＝120-116.2))

Total: 3 points

Fig. 3.4.5

Example of check sheet (Fixed type pneumatic fender with panel)82)

3.5 Cylindrical fender
3.5.1 Method of check/diagnosis and functional evaluation for cylindrical fender
In the initial check and diagnosis, periodic check and diagnosis and occasional check and diagnosis of cylindricalfenders, a field survey is conducted, and function is evaluated and recorded. The procedures for check/diagnosis andfunctional evaluation of cylindrical fender conform to Chapter 3.2 V-type rubber fenders. The flow of check/diagnosis
and functional evaluation is shown in Fig. 3.5.1.

Fig. 3.5.1 Evaluation flow of check/diagnosis for cylindrical fender
3.5.2 Damage rate of cylindrical fender by field survey
The dimensions of the damaged part on the rubber body are measured, and the respective damage rates arecalculated from the damaged length or damaged area.
(1) Length and area of damage
For tears, cracks, and burns, the damage rate is calculated from the damage length. The damage length is thesum of the projected lengths of damage to the longitudinal axis. This is written as damage length {L1, L2,…}.
83

For drops, missing rubber, chipping and wear, the damage rate is calculated from the damage area. The areaof damage is the product of the length and width of the damaged part. For calculation of damage length, thefollowing matters are considered.
a. More than one damage type
As for L1 and L2 shown in Fig. 3.5.2, damages occurring in the same part are calculated only
when the projection length to the longitudinal axis is longer (in the example, L1, L2 <L1). The L2
is considered to be included in the L1 part.
b. Damage perpendicular to the longitudinal axis of rubber fenderIf cracking occurs in the direction perpendicular to the longitudinal axis of the rubber fender,
as shown in L3 in Fig. 3.5.2, it is not included in the calculation of damage length because it does
not affect the deformation of the rubber body.
c. Inclined damage
As shown in the L5 part shown in Fig. 3.5.3, if the damage is inclined, measure the projected
length (L5) to the longitudinal axis.
d. Combination of damages
・ If the crack is continuous with a tear, include it in the tear and use the length of damage.
・ If the missing rubber is continuous to the drop, include the drop and use it as the area ofdamage.
・ When a tear and drop coexist, let each be the length of damage and the area of damage.
・ In the case of combinations other than the above, let each be the length of damage and thearea of damage.
(2) Calculation of the damage rate
The damage rate is the ratio of damaged length to the length of fender contacting face or the ratio of
damaged area to fender contacting face.
a. Tears, Cracks and Burns

Damage rate (%)＝

Total damage length
Length of fender contacting face×100
(3.5.1)b. Drops, Missing rubber, Chipping, Wear

Damage rate (%)＝

Total damaged area
Area of fender contacing face×100
(3.5.2)

1) Example of damage rate calculation
Examples of damage rate calculations for drops and tears are shown below.
a. Tears, Cracks and Burns
As shown in Fig. 3.5.2, when several damage types occur, measure the damage rate bymeasuring the length {L1, L2, L3, L4, L5} of each crack. When it occurs in the same part as in theL1 part and the L2 part, the longer L1 is taken. There is no damage length (L3) in the direction
perpendicular to the longitudinal axis. Therefore, L3 is ignored. As shown in Fig. 3.5.2, when thecrack (L5) is oblique, the projection length (L5) to the longitudinal axis is measured.

Damage rate (%)＝

｛L 1＋L 4＋L 5｝
L

84

×100
(3.5.3)

Fig. 3.5.2 Damage measurement (Cylindrical fender- Tear, Crack and Burn)
b. Drops, Missing rubber, Chipping and Wear
As shown in Fig. 3.5.3, if bulky damage occurs, measure the damage rate by measuring thelength {L6, L7} and width {W1, W2} of each damage area.

Damage rate (%)＝

｛L 6×W 1＋L 7×W 2｝
L ×D

×100
(3.5.4)

Fig. 3.5.3 Damage measurement (Cylindrical fender- Drop, Missing rubber, Chipping and Wear)

3.5.3 Functional evaluation
The functional evaluation of cylindrical fenders is divided into functional deterioration of the rubber body anddeterioration rank of accessories (supports). The score of functional deterioration of the rubber body iscomprehensively judged in consideration of the age of the fenders, the structure type of the quay, and the usage
condition of the ship. The degree of deterioration of supports is determined to be the deterioration ranking.
Rubber body:
The score of functional deterioration of the rubber body is determined by dividing the damage rate into six stages
and calculating the deterioration score that is obtained by adding the score shown for each deterioration mode anddamage rate.
Accessories (Supports):
The deterioration rank of supports is determined by dividing the visual condition of the part/member into four stages.
(1) Deterioration score of rubber body1) Method to score the deterioration
For the deterioration score of the rubber body, the score shown in Table 3.5.1 is added by eachdeterioration mode and damage rate. When there are two or more deterioration modes among (1) to (8),only the two larger scores are added, and the maximum ceiling is 12 points.
85

Table 3.5.1 Deterioration score table of rubber body (Cylindrical fender)
Damage rate
40% or30~39%
20~29%
10~19%
1~9%
Deterioration mode
more
(1) Drop (Area)
6
6
6
4
2
(2) Tear (Length)
6
6
6
4
2
(3) Missing rubber (Area)
3
2
1
0
0
(4) Crack (Length)
3
2
1
0
0
(5) Chipping (Area)
3
2
1
0
0
(6) Wear (Area)
1
1
1
0
0
(7) Burn (Length)
6
6
6
4
2
(8)

Age 20 years or more
1

Ozone crack

Photo 3.5.1 Example of damage(Cylindrical fender-Missing rubber)

0%
0
0
0
0
0
0
0

Age less than 20 years
0

Photo 3.5.2 Example of damage(Cylindrical fender-Tear)

2) Functional evaluation
The functional evaluation of the rubber body is based on the deterioration score based on Table 3.5.2.
Table 3.5.2 Functional evaluation of rubber body (Cylindrical fender)(Initial, Periodic and Occasional check/diagnosis)
Deterioration score

Functional evaluation

6 points or more

Significant functional deterioration

3~5 points

Functional deterioration started

1~2 points

Function will deteriorate if left unchecked

0 points

No functional deterioration

For measures, see Table 4.2.1 in 4.2.1 Measures for rubber body.

(2) Deterioration rank of accessories (Supports)
The deterioration rank of supports is judged based on the condition of the part and member based on Table
3.5.3.

86

Table 3.5.3 Function evaluation of supports (Cylindrical fender)(Initial, Periodic and Occasional check/diagnosis)
Deterioration rank
Condition of part and memberaBends, cuts or progressed corrosion were found,and further use is not recommendedb－－－c
Bends or corrosion observed, but further use ispossible.
d
No deterioration
For measures, see Table 4.2.2 in 4.2.2 Measures for accessories.

Photo 3.5.3 Example of damage rank “c”

3.5.4 Check sheet and record
Regarding the deterioration that has occurred in the rubber body and supports, record the state of deterioration foreach cylindrical fender on the check sheet. Fig. 3.5.4 shows an example of the check sheet for a cylindrical fender.

87Check sheet of Cylindrical fender
Location
Name of port
Fender size

Date ofinstallation
Name of quay
Fender ID○○ County○○ Port○○ φ300/φ150×1000 L

1. Rubber body○/ ○ / ○-5.0 mNo.1

Wharf No. ○○2. Accessories (Supports)○ / ○ / ○Date of inspection
Inspector
Items

Inspection result

Items

Inspection result〔Det. mode〕
(1)

Drop

(2)

Tear

(3)

Missing rubber

(4)

Crack

(5)

Chipping

(6)

Wear

(7)

Burn

(8)

Ozone crack

Det.
mode

Length orarea ofdamageDamage
rate

Det.
score

(2)

15 cm

15%

4

(3)

1200 cm2

40%

3

Total

7

Considerations whena) Age 20 years or moredeterioration score is3~5. If checked,b) Mooring 10,000 hours or more
replacement isc) Load sensitive quay structure
recommended.

□

Deterioration score

Measure for rubber
body

(1)

Bends

(2)

Cuts

(3)

Corrodeda Severe corrosion on chains

7□

Measure foraccessories□

Replacement

Replacement
No

Yes(Date of completion:

)

No

Yes

(Date of completion:

3. Background information (Photo, sketch, calculation)
Crack:
Damage rate =15/100×100=15%→Deterioration score 4 points
Missing rubber:

Photo or sketch ofdamageDamage rate = (20×20)/(30×100)×100=40%→Deterioration score 3 points

Process of functional
evaluation

Fig. 3.5.4 Example of check sheet (cylindrical fender)88)

3.6 Other rubber equipment
3.6.1 Method of check/diagnosis and functional evaluation for other rubber equipment
In the initial check and diagnosis, periodic check and diagnosis and occasional check and diagnosis of other rubber
equipment, a field survey is conducted, and function is evaluated and recorded. The procedures for check/diagnosis andfunctional evaluation of other rubber equipment conform to Chapter 3.2 V-type rubber fenders. The flow ofcheck/diagnosis and functional evaluation is shown in Fig. 3.6.1.

Fig. 3.6.1 Evaluation flow of check/diagnosis for other rubber equipment

3.6.2 Damage rate of other rubber equipment by field survey
The dimensions of the damaged part on the rubber body are measured, and the respective damage rates arecalculated from the damaged length or damaged area. Additionally, with regard to the removed rubber equipment, it isdetermined whether re-installation is possible according to the state of bolt hole damage.
(1) Length and area of damage
For tears, permanent deformation, cracks, separation and burns, the damage rate is calculated from the89damage length. The damage length is the sum of the projected lengths of damage to the longitudinal axis. Thisis written as damage length {L1, L2,…}.
For drops, missing rubber, chipping and wear, the damage rate is calculated from the damage area. The areaof damage is the product of the length and width of the damaged part. For the calculation of damage length,
the following matters are considered.
a. More than one damage area
As for L1 and L3 shown in Fig. 3.6.2, damages occurring in several parts are calculated only
when the projection length to longitudinal axis is longer (in the example, L3 is taken, L1 <L3 andL4 <L3). Therefore, L1 and L4 are considered to be included in the L3 part.
b. Damage perpendicular to the longitudinal axis of rubber equipment
If cracking occurs in the direction perpendicular to the longitudinal axis of rubber equipment,
as shown in L5 in Fig. 3.6.2, it is not included in the calculation of damage length because it does
not affect the deformation of the rubber body.
c. Inclined damage
As shown in Fig. 3.6.3, if the damage is inclined (L6), measure the projected length (L7) to thelongitudinal axis.
d. Combination of damages
・ If a crack is continuous with a tear, include it in the tear and use the length of damage.
・ If missing rubber is continuous to a drop, include the drop and use it as the area of damage.
・ When a tear and drop coexist, let each be the length of damage and the area of damage.
・ In the case of combinations other than the above, let each be the length of damage and thearea of damage.
(2) Calculation of the damage rate
The damage rate is the ratio of damaged length to the length of equipment or the ratio of damaged area of
equipment.
a. Tears, Permanent deformation, Cracks, Separation and Burns

Damage rate (%)＝

Damage length ｛L 1 , L 2, ・・・｝
Length of rubber body {L}×100(3.6.1)b. Drops, Missing rubber, Chipping and Wear

Damage rate (%)＝

Damage area
Area of rubber body×100
(3.6.2)(3) Example of damage rate calculation
Examples of damage rate calculations for tears and drops are shown below.
a. Tears, Cracks, Permanent deformation, Separation and Burns
As shown in Fig. 3.6.2, when several damages occur, measure the damage rate by measuring
the length {L1, L2, L3, L4, L5} of each crack. When it occurs in the same part as in the L1 part, L3part and the L4 part, the longest L3 is taken. There is no damage length (L5) in the direction
perpendicular to the longitudinal axis. Therefore, L5 is ignored.

｛L 2+L 3｝
×100
Damage rate (%)＝
L

(3.6.3)As shown in Fig. 3.6.3, when the crack (L6) is oblique, the projection length (L7) to the90

longitudinal axis is measured.

｛L 7｝
×100
Damage rate (%)＝
L

Fig. 3.6.2 Damage measurement(Crack - Rubber ladder)(3.6.4)

Fig. 3.6.3 Damage measurement(Oblique crack - Rubber ladder)b. Drops, Missing rubber, Chipping and Wear
As shown in Fig. 3.6.4, if bulky damage occurs, measure the damage rate by measuring thelength {L8, L9} and width {W1, W2} of each damage area.

Damage rate (%)＝

｛L 8×W 1＋L 9×W 2｝
L ×W

×100
(3.6.5)

Fig. 3.6.4 Damage measurement (Drop, Missing rubber - Rubber ladder)(4) Re-installing removed rubber equipment
If damage has occurred to the fixing holes (holes through which the fixing bolt passes through the fixing
flange) of the rubber ladder, corner protector, rubber net, etc., determine whether re-installation is possible
based on Table 3.2.1. Re-installation not recommended when damage occurs in one or more places. Whenmaking this judgement, you may refer to Photo 3.2.1 and Photo 3.2.2.
(5) Cuts on rubber ladder and rubber net
As shown in Figure 3.6.5, for the rubber ladder and rubber net, cutting of the step part of the rubber ladderand cutting of each grid part of the rubber net will cause fatal damage to the function, and thus each fracture91

must be checked.

Fig. 3.6.5 Steps of rubber ladder and grid of rubber net with fixing part3.6.3 Functional evaluation
The functional evaluation of the Other rubber equipment is divided into functional deterioration of the rubber bodyand deterioration rank of accessories (Fixings).
Rubber body:
The score of functional deterioration of the rubber body is determined by dividing the damage rate into six stages
and calculating the deterioration score that is obtained by adding the score shown for each deterioration mode anddamage rate.
Fixings:
The deterioration rank of supports is determined by dividing the visual condition of the part/member into four stages.
(1) Deterioration score of rubber body1) Method to score the deterioration
For the deterioration score of the rubber body, the score shown in Table 3.6.1 is added by eachdeterioration mode and damage rate. When there are two or more deterioration modes among (1) to (12),only the two larger scores are added, while the maximum ceiling is 12 points.
92

Table 3.6.1 Deterioration score table of rubber body (Other rubber equipment)
Damage rate
40% or30～39%
20～29%
10～19%
1～9%
Deterioration mode
more
(1) Drop (Area)
6
6
6
4
2
(2) Tear (Length)
6
6
6
4
2
(3) Permanent
6
6
6
4
2
deformation (Length)(4) Missing rubber (Area)
3
2
1
0
0
(5) Crack (Length)
3
2
1
0
0
(6) Chipping (Area)
3
2
1
0
0
(7) Separation (Length)
3
2
1
0
0
(8) Wear (Area)
1
1
1
0
0
(9) Burn (Length)
6
6
6
4
2
Re-installation not recommended6
Age 20 years or more
(11) Ozone crack
1
There is cut on step, grid or flange(12) Cut
6Note) Cut is for rubber ladder and rubber net.
(10)

0%
0
0
0
0
0
0
0
0
0

Re-installable
0
Age less than 20 years
0
No cuts
0

Bolt hole damage

Cut
Cut

Photo 3.6.1 Example of cut on step of Rubber ladder-Deterioration score “6 point”

Cut

Photo 3.6.2 Example of cut on flange of Rubber net-Deterioration score“6 points”

Cut1) Functional evaluation
Functional evaluation of the other rubber equipment is based on the deterioration score based on Table
3.6.2.
93

Table 3.6.2 Functional evaluation of rubber body (Other rubber equipment)(Initial, Periodic and Occasional check/diagnosis)
Deterioration score

Functional evaluation

6 points or more

Significant function deterioration

3~5 points

Functional deterioration started

1~2 points

Function will deteriorate if left unchecked

0 points

No functional deterioration

For measures, see Table 4.2.1 in 4.2.1 Measures for rubber body.
(2) Deterioration rank of fixings
The deterioration rank of fixings is judged based on the condition of the part and member based on Table
3.6.3.
Table 3.6.3 Functional evaluation of fixings (Other rubber equipment)(Initial, Periodic and Occasional check/diagnosis)
Deterioration rank
Condition of part and memberaLoose, bent, missing and/or cutb－－－cCorrosion observedd
No deterioration
For measures, see Table 4.2.2 in 4.2.2 Measures for accessories.

3.6.4 Check sheet and record
Regarding the deterioration that has occurred in the rubber body and accessories, record the state of deterioration foreach rubber equipment item on the check sheet. Fig. 3.6.6 shows an example of the check sheet.

94

Check sheet of Rubber equipment (Rubber ladder, Corner protector, Rubber net)
Date ofinstallation
Name of quay
Fender ID○○ County

Location○○ Port○○ 200H×1500 L

Name of port
Fender size

1. Rubber body○/ ○ / ○-5.0 mNo.1

Wharf No. ○○2. Accessories (fixings)○ / ○ / ○Date of inspection
Inspector
Items

Inspection result

Items

Inspection result〔Det. mode〕
(1)

Drop

(2)

Tear

(3)

Permnt. Deform.

(4)

Missing rubber

(5)

Crack

(6)

Chipping(7)

Separation

(8)

Wear

(9)

Burn

Det.
mode

(5)

Length orarea ofdamageDamage
rate

30 cm

20%

Det.
score

1

(1)

Loose

(2)

Bent

(3)

Missing

(4)

Cut

(5)

Corrodeda (One bolt missing)

6

(12)

(10) Bolt hole damage(11) Ozone crack

Total

7

(12) Cut

Deterioration score

Considerations when deterioration score is 3~5 andage is 20 years or more, replacement is recommended.
Measure for rubber
body

Bolt replacement

7□

Measure foraccessories

Replacement
No

Yes(Date of completion:

)

No

Yes

(Date of completion:)

3. Background information (Photo, sketch, calculation)
Crack:→Deterioration score 1 points

Photo or sketch ofdamageCut:→Deterioration score 6 points

Process offunctional
evaluation

Fig. 3.6.6 Example of check sheet (Rubber ladder, Corner protector, Rubber net)

〔References〕
1) Terauchi, K., T. Koizumi, S. Yamamoto, K. Hosokawa: Deterioration Actual State and the Function Evaluation of the
Rubber Fender, Technical Note of the Port and Harbour Research Institute, Ministry of Transport, Japan, No. 878,
1997 (Japanese)
2) Association for Innovative Technology on Fishing Ports and Grounds: Fender Replacement Criteria for Fishing Ports(Draft) (Functional evaluation document), 2007 (Japanese)95Chapter 4
Measures
4.1 Summary
4.1.1 General
It is generally accepted that rubber fenders eventually suffer from deterioration of function due to ageing, andpost-measures against those deteriorations must be taken about once or twice during the service period of a facility. A
decrease in the function of rubber fenders may cause the suspension of mooring operations at a harbour transportation
facility, and it is predicted that losses due to the facility's idleness will occur. In addition, even though the visualappearance may be normal, the performance of rubber fenders decreases due to age deterioration, which may cause
damage to mooring facilities and vessels. With regard to the rubber body, it is common to carry out replacement(update) as a post-measure because preventive measures are difficult or not economical. However, in the case ofpneumatic fenders, checking air pressure and repair and reinforcement of the rubber body are preventive maintenancemeasures.
In addition to replacement (update), measures for rubber fenders include repair, replacement of position of use, andservice restrictions. Appropriate measures can be taken from various viewpoints, such as deterioration status of rubber
fenders, importance of facilities, and economic efficiency.
The contents of the standard measures are shown in Table 4.1.1.
Table 4.1.1 Standards and references for rubber fenders
MeasureRemovalContents of measure
Remove when rubber fender is no longer needed.

Replacement (Update)Replacement (update) if preventive maintenance measures such as
repair are difficult or not economical. Measures such as in-service
suspension may be required during the renewal period.

RepairRepair when the performance and durability can be restored to a certain
level. Generally, it is difficult to recover the function of a rubber bodyby repair or reinforcement, but for pneumatic fenders, there are cases
where repair or reinforcement is possible, but technical knowledge isrequired for judgement. Measures such as in-service suspension may berequired during the repair period.

Re-positioning

Replace relatively frequently used rubber fenders with less frequently
used rubber fenders. During the handling period, suspension of service
may be required. In addition, for partial failure, methods such as
moving/rotating the position may be possible, but it is necessary toconsider secondary problems.

Service restriction

Change the berthing conditions (such as berthing speed), etc., tomoderate the condition in accordance with the reduced performance.
These limitations require technical knowledge about the possible
conditions for change. One must also ensure that they are informed tothe ship handling side. Therefore, it is practical to set them as an
emergency measure up to the implementation of other measures.

In addition, when deciding the repair method or the target range to take measures, it is necessary to conduct anadditional survey if information is not sufficient only with the periodic inspection and diagnosis results.

96

4.2 Measures for rubber fender
4.2.1 Measures for rubber body
Measures for the rubber body should be implemented appropriately based on the results of functional evaluation andcarried out according to the type of rubber fender and the deterioration status. In general, a rubber body is difficult torepair and reinforce, and measures are taken according to the degree of functional deterioration, as shown in Table
4.2.1.
Table 4.2.1 Measures according to deterioration score
Deterioration score
6 points or more

1)

Contents of measures
Replacement is recommended due to significant functional deterioration

3~5 points2)

It is desirable to re-position rubber fenders, service restriction, or replacethem as necessary, as their functions have been deteriorated.

1~2 points

If left unchecked, functional deterioration will progress, so care should
be taken, such as advancing the check and diagnosis timing.

0 points

Continue the current daily check and periodic check and diagnosis
because the function is maintained.

Note 1) If the deterioration score is 6 points or more, replacement is necessary, but the number of points
exceeding 6 points does not necessarily indicate the priority of replacement. The priority of replacement
should be determined by the facility manager taking into account the damage type, usage conditions andimportance.
2) If the deterioration score is 3 to 5, there is a concern about the impact of functional deterioration, so it isdesirable to replace it based on the following criteria (see Reference 2).
a. The age of the fender exceeds 20 years.
b. The total mooring time of ships exceeds 10,000 hours.
c. There is a concern that an increase in berth force or mooring force may cause structural problems(e.g., flexible quay such as dolphins).
In these measures, the damage shall be carefully checked, the cause shall be investigated, and the actual situation or
the condition of use shall be considered. In addition, rubber bodies such as rubber ladders, corner protectors, rubber
nets, etc., shown as other rubber equipment in Chapter 1 Section 1.2.1, take measures according to the deterioration
score according to Table 4.2.1.

4.2.2 Measures for accessories
Measures for accessories must be properly implemented depending on the type of accessories and the deterioration
situation.
Steel members:
If the performance of steel members such as fender panels, fixings, supports, etc. is lowered, it is necessary to takemeasures and select measures that satisfy the required performance. Since these steel members are generally subjected
to coated corrosion protection, it is necessary to take appropriate repair in consideration of the deterioration status ofcorrosion protection.
Other accessories (resin pads, used tyres, rubber sleeves, etc.):
For other accessories such as resin pads, used tyres, rubber sleeves, etc., it is difficult to repair them, so they should
be replaced (updated) according to the state of deterioration.

97

(1) Steel members
For steel members such as fender panels, fixings, supports, etc., select measures in accordance with the
Manual on Corrosion Prevention and Repair for Ports and Harbour Steel Structures (2009 edition) 1). The
measures according to the degree of deterioration of steel members are shown in Table 4.2.2.
Table 4.2.2 Measures for steel members according to deterioration rank
Deterioration rank

Contents of measuresaImplement replacement (update). In the case of loose fixing, retighten.

b－－－Consider such as advancing the periodic check and diagnosis timing.

c

For fender panel, repair the coated anticorrosive work such as painting as
needed.

dContinue daily check and periodic check and diagnosis.

Note: Regardless of the deterioration of steel members, when updating the rubber body, they may be
updated accordingly.
(2) Other accessories
Resin pads, used tyres and rubber sleeves used for pneumatic fenders are consumable members forpreventing damage to the hull of a berthing ship or damage to the fender body. Therefore, it is desirable to takemeasures such as updating before the function is completely lost. The measures corresponding to thedeterioration rank are shown in Table 4.2.3.
Table 4.2.3 Measures for other accessories according to deterioration rank
Deterioration rank

Contents of measuresaImplement replacement (update).

b

－－－

c

Consider advancing the periodic check and diagnosis timing.

dContinue periodic check and diagnosis.

Note: Regardless of the deterioration of other accessories, when updating the rubber body, they may be
updated accordingly.

〔References〕
1) Coastal Development Institute of Technology (CDIT): Manual on Corrosion Prevention and Repair for Ports andHarbor Steel Structure, No. 35, 2009 (Japanese)
2) Terauchi, K., T. Koizumi, S. Yamamoto, K. Hosokawa: Deterioration Actual State and the Function Evaluation of the
Rubber Fender, Technical Note of the Port and Harbour Research Institute, Ministry of Transport, Japan, No. 878,
1997 (Japanese)98Appendix

Appendix-A Fender control chart-------------------------------------------Appendix-B Standard form of fender check and diagnosis-------------Appendix-C Example of determining deterioration score-------------Appendix-D Example of deterioration rank for fixing--------------------

99

A-1
A-2
A-8
A-20

100

Appendix-A

Fender Control Chart

A-1

Appendix-B

Standard form of fender check and diagnosis

Check sheet of V type rubber fender
Location
Name of port
Fender size

Installation date
Name of quay
Fender ID

1．Rubber body

Y

M

D

2．Accessories (fixings)

Date of inspection
Inspector
Items

Y

M

D

Inspection result

Items

Inspection result〔Det. mode〕
(1)

Drop

Det.

Damage area

(2)

T ear

Mode

length(3)

Permnt. Deform.

(4)

Missing rubber

(5)

Crack

(6)

Chipping(7)

Separation

(8)

Wear

(9)

Burn

Damage
rate

cm

(1)

Loose

(2)

Bend

(3)

Missing

(4)

Cut

(5)

Corroded%cm(10) Bolt hole damage(11) Ozone crack

Det.
Score

%

Total

Deterioration score
When deteriorationa) Age 20 years or more
score is 3 ～5. Ifb) Mooring 10,000 hours or morechecked, replacement isc) Load sensitive quay structure
recommended.

M easures for Rubber
body

No

Yes

(Date of completion:

M easures forAccessories)

No

3．Background information (Photo, sketch, calculation)

Photo or sketch ofdamageProcess of functional
evaluation

A-2

Yes

(Date of completion:)

Appendix-B

Standard form of fender check and diagnosis
Check sheet of Rubber fender with Panel

Location
Name of port
Fender size

Installation date
Name of quay
Fender ID

1．Rubber body

Y

M

D

2．Fender panel

Date of inspection
Inspector
Items

Y

M

D

Inspection result(1)〔Det. mode〕
T ear

Det.

Damage area

(2)

Crack

Mode

length(3)

Permnt. Deform.

(4)

Separation

(5)

Burn

(6)

Bolt hole damage(7)

Ozone crack

Items

Damagerate

cm

Inspection result

Det.

(1)

Deformation

Score

(2)

Corrosion%cm%
T otalDeterioration score
When deteriorationa) Age 20 years or more
score is 3 ～5. Ifb) Mooring 10,000 hours or morechecked, replacement isc) Load sensitive quay structure
recommended.

M easures for Rubber
body

No Yes (Date of completion:

3．Fixings)

No Yes (Date of completion:

4．Supports

Items

Inspection result

Loose

(1)

(2)

Bend

(3)

Missing

(4)

Cut

(5)

Corrosded
No

Yes(Date of completion:)

Inspection result

Items

Bend

(1)

Wear

(2)

Cut

(2)

Abrasion(3)

Corroded

(3)

Cut

(4)

Missing

M easures for
Supports)

5．Resin pad

Items

(1)

M easures for
Fixings

M easurement for
Fender panel

No

Yes

(Date of completion:

6．Background information (Photo, sketch, calculation)

Photo or sketch ofdamageProcess of functional
evaluation

A-3)

M easures for
Resin pads

Inspection result

No

Yes

(Date of completion:)

Appendix-B

Standard form of fender check and diagnosis
Check sheet of Pneumatic fender

Location
Name of port
Fender size

PneumaticΦ

×

L-

Installation date
Name of quay
Fender ID

kPa

1．Rubber body

2．Air inlet valve,

Date of inspection
Inspector
Items

Y

M
Inspection result

Items

Level

3.

M

D

Body attachment

D
Items
Air inlet valve〔Det. mode〕
Degree of
airtight
maintenanceY

Condition

Det.

(1)

DamageScore(2)Corroded

Inspection result

Airtight
Det. Level

Deterioration
level

Body attachment

T otalPrevious pressurekPa (T emp.

℃）

(1)

DamageMeasured pressurekPa (T emp.

℃）

(2)

Corroded

Converted pressurekPa

Deterioration
score
When deterioration
score is 3 ～ 5. Ifchecked, replacement
is recommended.

M easures for
Rubber bodya) Age 20 years or moreb) Mooring 10,000 hours or more

M easureｓc) Load sensitive quay structure

No Yes (Date of completion:)

No Yes (Date of completion:

4. Net5. Mooring parts

Items

Inspection result

Items

Corroded

(1)

Bend

(2)

Cut

(2)

(3)

Crack

(3)

Cut
Corroded

(4)

Wear

(1)

)

M easure

Inspection result

M easure
No Yes (Date of completion:)

No Yes (Date of completion:

6．Background information (Photo, sketch, calculation)

Photo or sketch ofdamageProcess of functional
evaluation

A-4)

Appendix-B

Standard form of fender check and diagnosis
Check sheet of Fixed type Pneumatic fender with Panel

Location
Name of port
Fender size

Φ

×

H-

Installation date
Name of quay
Fender ID

kPa

1．Rubber body

2.Air inlet valve

Inspection dateInspector
Items

Y

M
Inspection result

Items

Level

M

3.Body attachment

D4.Fender panelD
Items
Air inlet valve〔Det. Mode〕
Degree of
airtight
maintenanceY

Condition

Det.

(1)

DamageScore(2)Corroded

Airtight

Inspection result

Body attachment

Det. Level
Deterioration
level

(1)

Damage(2)

Corroded

T otalPrevious pressurekPa (T emp.

℃）

Measured pressurekPa (T emp.

℃）

Converted pressurekPa

Fender panel(1)

Deformation(2)

Corroded

Det. Score
When deterioration
score is 3 ～ 5. Ifchecked, replacement
is recommended.

M easures for
Rubber bodya) Age 20 years or moreb) Mooring 10,000 hours or morec) Load sensitive quay structure

No Yes (Date of completion:

5. Fixings)

No Yes (Date of completion:

6. Supports

Items

Inspection result

Loose

(1)

(2)

Bend

(3)

Missing

(4)

Cut

(5)

CorrodedNo(Date of completion:

Inspection result

)

Items

Bend

(1)

Wear

(2)

Cut

(2)

Abrasion(3)

Corroded

(3)

Cut

(4)

Missing

M easures for
Supports

Yes)

7. Resin pad

Items

(1)

M easures for
Fixings

M easuresNo

M easures for
Resin pads

Yes

(Date of completion:

8．Background information (Photo, sketch, calculation)

Photo or sketch ofdamageProcess of functional
evaluation

A-5)

Inspection result

No

Yes

(Date of completion:)

Appendix-B

Standard form of fender check and diagnosis
Check sheet of Cylindrical fender

Location
Name of port
Fender size

φ

× φ

×

Installation date
Name of quay
Fender ID

L

1．Rubber body

Y

M

D

2．Accessories (Supports)

Date of inspection
Inspector
Items

Y

M

D

Inspection result

Items

Inspection result〔Det. mode〕
(1)

Drop

Det.

Damage area

(2)

T ear

Mode

length(3)

Chunk out

(4)

Crack

(5)

Chipping

(6)

Wear

(7)

Burn

(8)

Ozone crack

Damage
rate

cm

%

cm

%

Det.

(1)

Score

(2)

Cut

(3)

Corroded

Bend

T otalDeterioration score
When deteriorationa) Age 20 years or more
score is 3 ～5. Ifb) Mooring 10,000 hours or morechecked, replacement isc) Load sensitive quay structure
recommended.

M easures for Rubber
body

No

Yes

(Date of completion:

M easures)No

3．Background information (Photo, sketch, calculation)

Photo or sketch ofdamageProcess of functional
evaluation

A-6

Yes

(Date of completion:)

Appendix-B

Standard form of fender check and diagnosis
Check sheet of Rubber equipment (Rubber ladder, Corner protector, Rubber net)

Location
Name of port
Fender size

H ×

Installation date
Name of quay
Fender ID

L

1．Rubber body

Y

M

D

2．Accessories (Fixings)

Date of inspection
Inspector
Items

Y

M

D

Inspection result

Items

Inspection result〔Det. Mode〕
(1)

Drop

Det.

Damage area

(2)

Mode

length(3)

T ear
Permnt. Deform.

(4)

Missing rubber

(5)

Crack

(6)

Chipping(7)

Separation

(8)

Wear

(9)

Burn

(10)

Bolt hole damage(11)

Ozone crack

(12)

Cut

Damage
rate

cm

Det.

(1)

Loose

Score

(2)

Bend

(3)

Missing

(4)

Cut

(5)

Corroded

%

cm

%

Total

Deterioration score

When deterioration score is 3 ～5 and age is 20 years
or more, replacement is recommended.
M easures for Rubber
body

No

Yes

(Date of completion:

M easures)No

3．Background information (Photo, sketch, calculation)

Photo or sketch ofdamageProcess of functional
evaluation

A-7

Yes

(Date of completion:)

Appendix-C

Examples of determining deterioration score

1. Example of "Drop"
Definition：Progressed state of tear and missing rubber. There is no rubber that should be present in thefacing part of rubber body or leg part, and the absence of rubber reaches hollow part

（Judge）
Drop
100 %
↓
Deterioration. score
6 points
Dropped area｛L 1×W｝
18.8×150=
×100 =100%
Area of contacting face｛L×W} 18.8×150

Drop

Vertically installed（Judge）
Drop
20 %↓Deterioration. score
6 points

Dropped area｛L 1×W｝
25×40=
×100 =20%
Area of contacting face｛L×W} 25×200

Horizontally installed
Photo C-1 Example of damage（Drop）

A-8

Appendix-C

Examples of determining deterioration score

2．Example of "Tear"
Definition：A state in which a crack generated in facing part and leg part of rubber body advances andreaches hollow part.

（Judge）
Tear
23 %↓Deterioration. score
6 points

Torn length｛L 1｝35=×100 =23%
Length of contacting face｛L}150

Vertically installed（Judge）
Tear
47 %↓Deterioration. score
6 points

Torn length｛L 1｝70=×100 =47%
Length of contacting face｛L}150

Horizontally installed
Tear
Photo C-2 Example of damage（Tear）

A-9

Appendix-C

Examples of determining deterioration score

3．Example of "Permanent deformation"
Definition：A state in which the facing on rubber body, legs, and fixing flange are deformed and do not
return to their original shape.

（Judge）
Permanent deformation
50 %↓Deterioration score
6 points

Deformed area｛L 1×W｝
18.8×75=
×100 =50%
Area of contacting face｛L×W}
18.8×150

Permanent deformation

Photo C-3 Example of damage（Permanent deformation）

A-10

Appendix-C

Examples of determining deterioration score

4．Example of "Missing rubber"Definition: The rubber has been scraped off at contacting face of rubber body, but has not reached the hollow
part.

（Judge）
Missing rubber
50 %↓Deterioration score
3 points

Missing rubber area｛L 1×W｝
25×50=
×100 =50%
Area of contacting face｛L×W}
25×100Missingrubber（Judge）
Missing rubber
50 %↓Deterioration score
3 points

Missing rubber area｛L 1×W｝
18.8×75=
×100 =50%
Area of contacting face｛L×W}
18.8×150

Photo C-4 Example of damage（Missing rubber）

A-11

Appendix-C

Examples of determining deterioration score

5．Example of "Crack"
Definition：The rubber surface is partially cut at contacting face and leg part of rubber body, but it has notreach the hollow part.

（Judge）
Crack
15 %
↓
Deterioration score
0 point

Crack length｛L 1｝=
Length of contacting face｛L}15×100 =15%
100（Judge）
Crack
13 %
↓
Deterioration score
0 point

Crack length｛L 1｝=
Length of contacting face｛L}Crack
Photo C-5 Example of damage（Crack）

A-12

20
×100 =13%150

Appendix-C

Examples of determining deterioration score

6. Example of "Chipping"
Definition: A group of small damage on surface of rubber body.

（Judge）
Chipping
67 %↓Deterioration score
3 points

Chipping area｛L 1×W｝
18.8×100=
×100 =67%
Area of contacting face｛L×W} 18.8×150

Chipping（Judge）
Chipping
50 %↓Deterioration score
3 points

Chipping area｛L 1×W｝
18.8×75=
×100 =50%
Area of contacting face｛L×W}
18.8×150

Photo C-6 Example of damage（Chipping）

A-13

Appendix-C

Examples of determining deterioration score

7. Example of "Separation"
Definition：The condition that rubber of surface and side of fixing flange of rubber body is separated fromembedded steel plate.

（Judge）
Separation
50 %↓Deterioration score
3 points

Separated length {L 1}75=
×100 =50%
Length of fixing flange{L}150

Separation（Judge）
Separation
50 %↓Deterioration score
3 points

Separated length {L 1}75=
×100 =50%
Length of fixing flange{L}150
Photo C-7 Example of damage（Separation）

A-14

Appendix-C

Examples of determining deterioration score

8. Example of "Wear"
Definition：The corner of contacting face of rubber body is worn out (rounded).

（Judge）
Wear
80 %↓Deterioration score
1 point

Worn area｛L 1×W｝
18.8×120=
×100 =80%
Area of contacting face｛L×W}
18.8×150（Judge）
Wear
20 %↓Deterioration score
1 point

Worn area｛L 1×W｝=
Area of contacting face｛L×W}

Photo C-8 Example of damage（Wear）

A-15

25×20
×100 =20%
25×100Appendix-C

Examples of determining deterioration score

9. Example of "Ozone crack"
Definition：A state in which an infinite number of small cracks are generated on rubber surface of contacting
face, legs, hollow part, and fixing flange of rubber body.

（Judge）
Deterioration score
2 points
1 point for the age older than 20
years, plus 1 point for hazardous
material (LNG berth).

Photo C-9 Example of damage（Ozone crack）

A-16

Appendix-C

Examples of determining deterioration score

10. Example of "Combination of damages"
Definition：There is not only one deterioration mode but a combination of various deterioration modes.
1) Crack and Missing rubber（Judge）
Crack
Missing rubber
0%
23 %
↓
↓
Det. score
Det. score
0 point
1 point（Add）
Total deterioration score
1 point
・Crack

L2＝0 cm（perpendicular tolongitudinal axis）

・Missing rubber

Missing rubber area｛L 1×W｝
25×35=
×100 =23%
Area of contacting face｛L×W}
25×1502) Missing rubber and Separation（Judge）
Missing rubber
Separation
70%
80 %
↓
↓
Det. score
Det. score
3 points
3 points（Add）
Total deterioration score
6 points

Missing rubber area｛L 2×W｝
25×70=
×100 =70%
Area of contacting face｛L×W}
25×100
Separated length {L 1}80=
×100 =80%
Length of fixing flange{L}100

Photo C-10 Example of damage（Combination of damages-1）
A-17

Appendix-C

Examples of determining deterioration score

3) Drop and Missing rubber（Judge）
Drop
Missing rubber
50 %
25 %
↓
↓
50 % ＋ 25 %＝75 %（Include in Drop)
Total deterioration score
6 points(50+25)×25
Dropped area (L 1+L 2)×W=
×100 =75%
Area of contacting face｛L×W}
25×1004) Drop and Tear

（Judge）
Drop
Tear
30 %
50 %
↓
↓
Det. score
Det. Score
6 points
6 points（Add）
Total deterioration score
12 points

Dropped area｛L 1×W｝=
Area of contacting face｛L×W}

25×30
×100 =30%
25×100Torn length｛L 2｝50=
×100 =50%
Length of contacting face｛L}100

Photo C-11 Example of damage（Combination of damages-2）

A-18

Appendix-D

Example of deterioration rank for fixing① Loose of bolt

(Judge)Deterioration ranka

② Bend of bolt

(Judge)Deterioration ranka

③ Missing of bolt

④ Cut of bolt

(Judge)(Judge)Deterioration rank

Deterioration rankaaPhoto D-1 Example of deterioration rank (Fixings)

A-19

Appendix-D

Example of deterioration rank for fixing⑤ Corrosion of bolt

Progress of corrosion

a. No corrosion(Judge)Deterioration rankdb. Corroded (decoloration)(Judge)Deterioration rank

dc. Corroded
Bolt decoloration(Judge)Deterioration rankdWasher red rust
(Judge)Deterioration rankcd. Corroded (Red rust)(Judge)Deterioration rankce. Corroded (swelling of substrate)(Judge)Deterioration rankaPhoto D-2 Example of deterioration rank (Corrosion)

A-20

CDIT Library No. 2
Guidelines for Maintenance of Rubber Fender systems
September 2019
Coastal Development Institute of Technology
Shimbashi SY Building, 5F
1-14-2, Nishishimbashi, Minato-Ku, Tokyo 105-0003
TEL :+813-6257-3701
URL: http://www.cdit.or.jp