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Many regulations and publications on the survey and operation of tankers require that the Owner, or his manager, applies "effective maintenance" or "normal Maintenance" to the ship's structure. The documentation required for planning class renewal surveys includes records of Owner's inspections, which are to form part of the survey report file on board. The certificates issued by some classification societies state that the ship is classed "subject to normal maintenance". However, when asking different tanker Owners what they understood by "normal maintenance", all had their own ideas and it was apparent that there is no internationally accepted concept of "normal circumstances", even allowing for the fact that tankers of different ages and designs will require different approaches to maintenance.
The Tanker Structure Co-operative Forum (TSCF) has published several Manuals on the Maintenance and Repair of Structures, but these have never been assembled in a format which provides an answer to the question "what is meant by effective maintenance?" The purpose of this manual, therefore, is to draw on previously published guidance, combined with the latest experience of the TSCF's and INTERTANKO's membership to produce a book that can be used by any Owner or manager of any tanker afloat as a guide to effective maintenance of the structure. Advice on how inspection and maintenance can be facilitated by improved design is included in Appendix 3.
Furthermore, the Guide suggests practices for the various elements of maintenance, such as paint condition, steel thickness and handling of fractures.
If an Owner adopts the practices set down in this manual, he should be confident that he will meet the ISM requirement to establish procedures to ensure that the ship's structure is maintained in conformity with the provisions of relevant rules and regulations.
Chapter 1 INTRODUCTION
Chapter 2 REGULATORY REQUIREMENTS FOR MAINTENANCE
2.2 International Maritime Organisation Conventions
2.2.1 Safety Management Systems
2.2.2 Enhanced surveys
126.96.36.199 Survey Programme
188.8.131.52 Documentation Onboard
2.2.3 Condition Assessment Scheme
2.3 Classification Rules
2.3.2 Special survey
2.3.3 Annual Survey
2.3.4 Intermediate Survey
2.3.5 Drydocking (Bottom) Survey
2.3.6 Damage and Repair Surveys
2.3.7 Voyage Repairs and Maintenance
Chapter 3 REVIEW OF TYPICAL DEFECTS
3.1.1 Uncoated Surfaces
(a) General Corrosion
(b) Pitting Corrosion
(c) Grooving Corrosion
(d) Microbially Influenced Corrosion (MIC)
3.1.2 Coated Surfaces
(a) Localised Corrosion
(b) Pitting Corrosion
(c) Grooving Corrosion
3.2 Structural Elements Important for Global Strength
3.2.1 Bottom Structures
3.2.2 Side Shell, Longitudinal and Transverse Bulkheads
3.2.3 Deck Structures
3.2.4 Vibration Damage
3.3 Local Strength Issues
184.108.40.206 Fatigue Analysis
220.127.116.11 Typical Locations for High Sensitivity to Fatigue Failure
18.104.22.168 The Effect of Higher Tensile Steel (HTS)
3.3.3 Brittle Fracture
Chapter 4 INSPECTION AND MAINTENANCE OBJECTIVES
4.1 Benefits and Challenges
4.2 Vessel Age, Design, Operational Profile and Cargoes Factors affecting Scope of Inspection
4.2.1 Vessel Age
4.2.3 Operational Profile
Chapter 5 INSPECTION PROGRAMMES
5.1 The Inspection and Maintenance Plan ("IMP")
5.1.1 Structure Included in the Scope of an IMP
5.1.2 Types of Inspection Conducted by Owners
22.214.171.124 General Condition Inspections
126.96.36.199 Detailed Condition Inspections
188.8.131.52 Repair Specification Inspections
5.1.3 Frequency of inspections
5.2 Development of the Inspection and Maintenance Plan (IMP)
5.3 Inspection Preparation
5.3.1 Identification of Areas for Inspection
5.3.2 Access and Reachability for Inspection
184.108.40.206 Safe Entry Requirements
220.127.116.11 Accessibility of the Areas of the Space to be Inspected
1. Temporary Staging
2. Mobile Platforms
4. Remotely Operated Vehicles (ROVs)
5. Use of Divers
6. In Tank Camera
7. Industrial Rope Access
8. Other Devices
5.4 Inspection Execution
5.4.1 What to look for and where
18.104.22.168 Fore Peak Tanks
22.214.171.124 Aft Peak Tanks
126.96.36.199 Wing Tanks
188.8.131.52.1 Cargo Tanks
184.108.40.206.2 Ballast Tanks
220.127.116.11 Centre Cargo Tanks
18.104.22.168 Double Bottom Ballast Tanks
22.214.171.124 Double Side Ballast Tanks
126.96.36.199 Deck Area Structure
188.8.131.52 Shell Plating
184.108.40.206 Bunker and Fresh Water Tanks
220.127.116.11 Other Accessible Spaces
18.104.22.168 Sea Connections and Overboard Discharges
22.214.171.124 Sea Chests
126.96.36.199 Rudders, Rudder Horn, Sternframe
5.5 Inspection reports
5.5.1 Report Content
5.5.2 Report Format
5.6 Inspection result analysis
5.6.1 Steel Condition
5.7 Acceptance criteria
5.7.1 Thickness measurements
188.8.131.52 Isolated area
184.108.40.206 Structural Element
220.127.116.11.1 Pitting intensity
18.104.22.168.2 Acceptable wastage
5.8 Revision of IMP
Chapter 6 MAINTENANCE AND REPAIR OF THE HULL STRUCTURE
6.2 General Requirements
6.3 Steel Repair Practice and Quality Standard
6.3.1 Welded Repairs Afloat
6.3.2 Welded Repairs in Drydock
6.3.3 Renewal of Plates
6.3.4 Renewal of Internals
6.3.5 Insert Plates
6.3.6 Large Shell Plate Insert with Stiffeners
6.3.7 Welding of Pits and Grooving
6.3.9 Fatigue Cracks
22.214.171.124 Stopping and Welding
126.96.36.199 Preventive Measures
6.3.10 Grinding of Shallow Cracks
Chapter 7 PROTECTION AGAINST CORROSION
7.1 The Causes and Types of Corrosion
7.2 Corrosion Control
7.2.2 Coatings Paint
188.8.131.52 Organic Coatings
184.108.40.206 In-organic Paint Coatings
7.2.4 Failure of Inorganic Primers, Galvanising, Cladding
7.3 Composite Systems Brief Overview
7.3.1 Hull coating Antifouling systems
7.4 Specific Shipboard Applications and Conditions
7.4.1 Ballast Tank Coatings
7.4.2 Potable Water Tank Coatings
7.4.3 Other Fresh Water Tank Coatings
7.4.4 Cargo Tank Coatings
7.4.5 Microbially Influenced Corrosion
7.5 Cathodic Protection Systems
7.5.2 Anode Design Basis for Ballast Tanks
7.6 IACS Guidelines for In-service Monitoring Reports
7.7 Repairs in Service In Service Maintenance of Coating Systems
7.7.2 Repairs in Yard versus Repairs at sea
7.7.3 Methods of Surface Preparation
7.7.4 The Steps for Tanks Coating Maintenance/Repairs
7.7.5 Major Considerations
Pitting Intensity Diagrams
Example of an Inspection and Maintenance Plan, including sample report forms for copying
Designing for ease of Inspection and Maintenance
1. Use of Higher Tensile Steel
2. Cargo Tank Corrosion Problems
3. Inspection of cargo tanks
4. Inspection in Ballast Tanks
Preparation for Coating
Examples of Permanent Means of Access
List of Standards in Preparation and Coating
Definition of "Areas under Consideration"
Title: INTERTANKO Guidance Manual For Maintenance Of Tanker Structures (downloadable product)
Product Code: WS1023EA
Published Date: January 2008
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