1) IACS Common Structural Rules (CSR) were developed to provide a unified set of standards for ship structures to replace individual society rules and align with upcoming IMO Goal-Based Standards (GBS). 2) GBS establishes high level safety objectives while CSR and industry guidelines provide detailed verification criteria and requirements. IMO sets goals, IACS develops rules meeting goals, and industry develops best practices. 3) Studies of freak waves found their probability of occurrence is lower than previously believed and more data is needed to accurately account for them in ship design risk assessments.

1. Reviw JAMS
Ship design rules and regulations – an
overview of major theme

2. An overview of major themes
IMO Goal-
Based
Standards
IACS Common
Structural Rules
* Freak Waves
Risk-Based
Approach

3. Role of IACS
•SETTING
•IMPLEMENTING
•MONITORING
RULES’
Hull
structure +
machinery
engineering

4. What are the class rules
Complying with Class Rules:
- Provision of adequate global strength;
(ships capable of withstanding still water and wave induced
loads with the specified stress criteria)
- Provision of adequate local strength of
individual components
(steel material requirements and scantling formulations are
to ensure that ships resist modes of buckling, fatigue,
yielding, brittle fracture)
- Rules provide direct calculations
procedures for determination of
scantlings.

5. Relation with IMO and flag States
IMO Conventions – Statutory Requirements
SOLAS Convention states that in addition to the Conventions requirements,
ships shall be designed, constructed and maintained in compliance with
class rule requirements of a classification society which is recognized by
the Administrations;
Many of the flag States authorize class societies to apply the IMO
Conventions (statutory req.) on their behalf by design appraisals and
surveys.

6. What IACS can not do
A strength of “classification” concept is
that the Societies act as independent
bodies, giving an independent and
unbiased assessment of the status of
ship’s hull and machinery;
However, they are not guarantors of the
safety as they have no control over
how a ship is operated and maintained.

7. The current regulatory
framework – shipping safety
Coastal State
Regulations
Flag State
Regulations
Underwriting
Clauses
Operational
Procedures
Industry
Standards
Classification
Rules
International
Conventions &
Regulations
Safety & Quality
Management
Systems
Port State
Controls
Chartering &
Vetting
Criteria

8. Risk-Based Approach in shipping
In many cases, enhancing the safety rules (structure
incl.) were driven by accidents;
Following high profile accidents (Herald of Free
Enterprise, Exxon Valdez, Piper Alpha), a risk-based
approach in ship design and operation was
introduced;
IMO, supported by IACS, recommends FSA to be
applied, to examine potential areas and introduce
risk reduction measures before a tragedy happens.
Bulk Carriers – top priority.

9. Example: BC Accidents Trend
LOSS OF LIVES
0
20
40
60
80
100
120
140
160
180
200
1990
1992
1994
1996
1998
2000
2002
Years
No.
lives
lost
BULK CARRIER LOSSES
0
5
10
15
20
25
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
Years
No.
vessels
lost
0 10 20 30
Collision
Grounding
Structural
Flooding
Machinery
fire/explosion
Machineryfailure
Cargo
loading/unloading
Cargo
fire/explosion
Cargo
shift/capsize
Contact object
Unknown
1993-2001
2002
Source: INTERCARGO Annual Report 2002

10. Changes
• A systematic method is put in place to establish the ship
safety rules of the basis of assessment of risks, costs and
benefits – final decisions are now robust and defensible.
• However, this risk-based approach “supplements” the
traditional prescriptive rule-making, allowing variation from
prescriptive rules, provided that the ship (system) risks are
maintained at acceptable levels.
Widespread consensus -
Make ships durable and fit-for purpose

11. Expectations
Regulatory
Expectation
Safe
Environmentally
friendly
Easy for inspection
and maintenance
Industry
Expectation
Robust and Reliable
Fit for purpose
User friendly
Goal-Based Standards
Common Rules

12. New regulatory framework
2
3
REGULATION
SELF-
REGULATION
Safety
objectives
Risk
acceptance
criteria
Prescriptive rules
Policies, management systems and best practices
Operational requirements

13. Objectives – Common Structural
Rules
• To eliminate competition between class
societies on standards
• To embrace the intentions of the anticipated
IMO requirements for Goal-Based Standards
for new buildings
• To ensure that a ship meeting these new
standards will be recognised by industry as
being safe, robust and fit for purpose as would
have been required
• To employ the combined experience of all class
societies to develop an agreed standard, or set
of Rules

14. IACS Common Structural Rules
Net scantling approach
Buckling and ultimate limit state of the hull girder
Dynamic loading
Fatigue life
Coating life
Transparency and ease of use: (Under the old rules, the
corrosion margin is given as a percentage, now an
absolute min figure corrosion margin)
Draft Rules:
– Fatigue life [ 25 years ]
– Coating life [ 10 years ]
– Corrosion additions [ 25 years ]
– Structural strength intact conditions
– Residual strength assumed damaged

15. Principal new elements
• Net scantling approach is used throughout the
new Rules
• Inclusion of procedures for the assessment of
buckling and ultimate limit state of the hull girder
• Inclusion of new methods for describing dynamic
loading
• Inclusion of new methods for determination of the
fatigue life
• Development of a Rule format that provides
transparency and ease of use

16. New regulatory framework
SELF-
REGULATION
Safety
objectives
Risk
acceptance
criteria
Prescriptive rules
Policies, management systems and best practices
Operational requirements
IMO
Goal-Based
Standards

17. Goal-Based Framework
Goal Based Safety
Objectives
Goal Based Functional
Requirements
Goal Based Verification of
Compliance Criteria
Tier I
Tier II
Tier III
Industry Standards, Codes of Practice and Safety and
Quality Systems for Shipbuilding, Ship Operation,
Maintenance, Training, Manning, etc.
Tier V
IACS Common Rules,
Technical Procedures and Guidelines
Tier IV
IMO
Goal
Based
Standards
GBS represents the top tiers of framework, against which the ships safety
is verified both at design and construction stages and during the operation

18. Mechanism
The mechanism by which the goal-based
standards will be put in place is:
• IMO sets the goal;
• IACS develops class rules that meet
the so-determined goals;
• Industry and IACS develop detailed
guidelines and recommendations for
wide application in practice.

19. Goal Based Standards + IACS
Rules
Optional sub
systems and components
Optional sub
systems and components
Detailed rule requirements
Detailed rule requirements
Major systems and
equipment
Major systems and
equipment
Main ship
functions
Main ship
functions
Overall
objectives
Functional
Requirements
Goals
Rules
IMO
Class

20. Example: Safety Objectives
Goal Based Safety
Objectives
Goal Based Functional
Requirements
Technical Procedures and Guidelines, IACS
Common Rules
Industry Standards, Codes of Practice and Safety
and Quality Systems for Shipbuilding, Ship
Operation, Maintenance, Training, Manning, etc.
Goal Based Verification of
Compliance Criteria
Tier I
Tier II
Tier III
Tier IV
Tier V
IMO
Goal
Based
Standards
Design Life
Environmental Conditions
Structural Safety
Structural Accessibility
Quality of Construction

21. Example: Functional
Requirements
Goal Based Safety
Objectives
Goal Based Functional
Requirements
Technical Procedures and Guidelines, IACS
Common Rules
Industry Standards, Codes of Practice and Safety
and Quality Systems for Shipbuilding, Ship
Operation, Maintenance, Training, Manning, etc.
Goal Based Verification of
Compliance Criteria
Tier I
Tier II
Tier III
Tier IV
Tier V
IMO
Goal
Based
Standards
Fatigue Life
Coating Life
Corrosion Additions
Strength Criteria

22. Verification Criteria
 Compliance with the goal-based standards during shipbuilding
 Plan review and approval
 Structural calculations
 Surveys during construction
 Compliance with the goal-based standards on ships-in-service
 Periodic surveys and thickness measurements
 Structural reassessment based on survey and thickness measurements

23. Deliverables
• A new complete set of Rule covering the
structural requirements for oil tankers and bulk
carriers for new construction and for those ships
subsequently in service.
• Supporting guidance to amplify the Rules,
including the procedures for carrying out direct
calculations and for fatigue life assessment.
• Background documents explaining the implicit
safety levels, design principles and assumptions
on which the Rules are based.
• IACS Common Structural Rules will be in line
with the IMO Goal-Based Standards.

24. Freak Waves Findings
• Traditionally, this type of waves have been observed only
occasionally under unexpected conditions. However, by
virtue of an advance mode of measurement and data
analysis techniques, such an occurrence is analyzed;
• Better understanding of the mechanism generating such
waves has been gained;
• The analysis of casualty database and the forecast of
such waves can lead to the development of a mechanism
by which masters can be alerted so as to enable them to
take precautionary action;

25. Freak Waves Findings
For future study:
• The design practice is moving a more consistent probablistic
method, e.g. Extremes are determined for a given return period –
expected lifetime of the structure. For consideration in ship
design, the probability of occurrence and also the probability of a
ship encountering such waves are needed. This involves a rigirous
analysis of shipping casualty data. Lack of information of the core
causes of the reported casualties can lead to a misleading or
unfounded conclusion.
• According to the Maxwave study, due to their extreme steepness,
they last for very short period of time before breaking. Hence, the
probability of a ship meeting such waves is even lower that the
actual occurrence of freak waves in open ocean;
• Shape of freak wave profiles in space and time including their
kinematics and ship responses to freak waves are to be
documented.

26. Freak Waves Findings
• A distinction between the offshore platform and moving ships
• The validity of a non-linear theory and mathematical model for
freak waves needs be verified. END

28. CSR + GBS