1. American Bureau of Shipping Introduction To ABS Rules
Presentation to the Naval Academy
6 April 2005

2. What is Classification?
Classification is third party certification
in the marine industry
Classification is a process which certifies
adherence to a recognized set of technical
standards, representing that a ship or other
type of marine structure is structurally sound
and mechanically fit for its intended purpose.

3. The Classification Process
Develop Technical Standards (Rules)
Developed through industry-based
technical committee structure
Embraces recognized external standards
Updated annually
Customized when necessary
(new technology/new application)
Implement Technical Standards
Design Plan review and engineering analysis
Survey during construction
Periodic survey throughout vessel life

4. The Classification Process
Rules and Guides
Rules are the foundation of the process
Over 60 sets of Rules and Guides
Developed with industry
Redundant
Propulsion
Guide
MODU Rules
High Speed Craft Guide
SWATH Guide
Steel
Vessel Rules
Naval Vessel Rules
Industry Committee Based
Peer review from all relevant parties
Continual feedback and update
Calibrated to proven experience

5. ABS - a Snapshot
world leader in ship safety and environmental protection since 1862
1500 people offices
81 countries ISO 9000 certified
60+ Rules and Guides
10,000 ships in class (250+ Government)
totaling over 100 million gross tons
20,000 manhours engineering review per month
708 new construction ships under survey (15 million gross tons) A
Industry and Government Involved in Management and Operations

6. Engineering Group OED - Offshore Engineering Department
AA - Advanced Analysis Department
SED - Ship Engineering Department
Materials & Welding Department
Naval Engineering Department

7. Ship Engineering Department
Tanker / Bulk Carrier / Ship Safety Group
General Cargo Ship Group
Tonnage
Load Line Stability Group

8. ABS Rules Steel Vessel Rules
Steel Barges - Ocean Service Barges of any Length
Steel Vessels Under 90 m - Crewboats, Tugs
High Speed Naval Craft- Patrol Boats HSVs
Steel Vessels for Service on Rivers, ICW - River Barges, Towboats
Bulk Carriers for Service on the Great Lakes - Freshwater Operations
Reinforced Plastic Vessels - F. R. P. Vessels
Aluminum Vessels - Aluminum Commercial Vessels 100’ - 500’
Naval Vessel Rules
MODU - Mobile Offshore Drilling Units

9. ABS Guides Motor Pleasure Yachts - Steel, Aluminum, or FRP
High Speed Craft, - Commercial/Government Service Planing vessels
Fishing Vessels - Steel Fishing Vessels Under 90 m (200’)
Offshore Racing Yachts - Steel, Aluminum, or FRP Sailing Vessels
Fire Fighting Vessels - Steel Fireboats
Crew Accommodations Guide
Oil Recovery Vessels - Oil Spill Cleanup Vessels
Floating Production Storage and Offloading Vessels - (FPSO)
Small Waterplane Area Twin Hulled Vessels - (SWATH)

10. Ship Acquisition Process
MNS
ORD
A-Spec
Requirement Derivation RULES
B-Spec
Optional Step
C-Spec
Owner
Build-to-
Print
Contractor
Technical Validation CLASSIFICATION

11. Function - Fitness - Safety
Owner’s Requirements
not addressed elsewhere
mission related
owner unique
Detailed
Component and
Performance
Standards
Classification Rules
structural and mechanical fitness
physical attributes of ship
Statutory Compliance
safety of life issues
environmental protection
Baseline Technical Standards

12. Hull Classification Considerations
Intact and Damaged Stability
Specialized Vessel Criteria
Freeboard Assignment
Strength of Hull Structure
Longitudinal Strength Requirements
Local Strength Requirements
Condition Assessment
Surveys During Construction
Surveys In-Service

13. Structural Analysis 1. Load Determination - “What are the Loads?’
2. Response Determination - “How do these loads affect the Structure?”
3. Strength Evaluation - “Are the structural arrangements and materials adequate for the determined response?”

14. Ship Structure Longitudinal Strength (Continuous Members)
Local Plating/Stiffener Requirements
Main Supporting Members
Longitudinal/Transverse Bulkheads
Web Frames
Appendages
Rudder/Skeg
Bilge Keel
Materials
Grade ( Strength & Toughness )
Castings / Forgings
Welding

15. Longitudinal Strength Unified IACS Requirement
Still Water Bending Moment
Wave Bending Moment
Hogging Condition
Sagging Condition
Total Bending Moment

20. Strength Evaluations Material Selection Failure Modes
Grade (Strength vs. Toughness)
Castings/Forgings
Welding
Service Temperature
Thickness
Failure Modes
Yielding
Buckling
Fatigue
Fracture

21. Fatigue Assessment Description of the Environment
Calculations of Ship Motions, Sealoads, and Local Hydrodynamic Pressures
Calculations of Structural Response and Stress Transfer Function
Selection of Appropriate S-N Curves and Stress Concentration Factors
Estimation of Fatigue Life and Comparison with Acceptance Criteria

23. Approach to Hull Classification
Semi–Empirical
Approach to Hull Classification
Longitudinal Strength P
Yielding (Explicit)
Buckling (Both)
Local Strength
Analysis
Response
Determination
Fatigue (Implicit)
Main Supporting
Fracture (Implicit)
Members
Material Requirements
Strength vs.
Toughness

24. Semi-Empirical Rules Derived from First Principles
Stiffeners (beams)
Assume Fixed End Beams where M = wl2 / 12
w = s h & SM= M / Fb
Allowable Stress Fb = KSI or 20.16KSI for Ordinary Steel Fy =34KSI
ABS Rule
SM= ,0041 c h s l2

26. Safehull Project Objective “ A Completely Restated Set of Hull Design and Evaluation Criteria”
Establish Loads and Combinations Acting on the Global and Local Structure
Specify the Extent and Types of Analyses Required to Determine Loads
Establish the Required Strength of the Structure to Resist Load Effects

27. Traditional Approach Nominal Loading - Prescribed
Simple Design Equations in Rules
Calibrated by Satisfactory Service Experience

28. Modern Approach Expected Loading - Calculated
Analysis Methods to Establish Load Effects
Strength Performance Criteria Under Demands of Loads

29. Net Ship Approach
Design Strength is Evaluated with Expected Corrosion Values Removed
Nominal Strength can be Preserved for the Entire Life of the Vessel
Appropriate Corrosion Margins can be added to Accommodate Longer Design Lives
Allows Explicit Means to Assess Sensitivity of Structural Strength to Corrosion

30. Net Ship Concept
Corrosion
Fatigue
Corrosion/Fatigue Interaction

32. Corrosion Margins Recommended Corrosion Location/Structural Element
Margin for Class (mm)*
Cargo Tank
Ballast Tank
Effectively Coated
Deck Plating
1.0
2.0
Side Shell Plating
N.A
1.5
Bottom Plating
N.A
1.0
Innerbottom Plating
1.5
1.5
Longitudinal Bulkhead Plating
1.0
1.5
Transverse Bulkhead Plating
1.0
1.5
Transverse & Longitudinal Deck
Supporting Members
1.5
2.0
Double Bottom Tank Internals (Stiffeners,
Floors and Girders)
N.A
2.0
Vertical Stiffeners and Supporting
Members Elsewhere
1.0
1.0
Non-vertical Longitudinals/Stiffeners and
Supporting Members Elsewhere
1.5
2.0

36. Load Components Determined Through Parametric Seakeeping Analysis
Hull Girder Loads
Still Water and Wave Induced Bending Moment and Shear Force
Vertical, Horizontal and Torsional
Internal Tank Pressure
Added Pressure Head due to Roll and Pitch
Internal Forces due to Accelerations
Sloshing
External Pressure
Hydrostatic Pressure Distribution
Wave Induced Dynamic Pressure Distribution

39. Load Determination North Atlantic Route Strip Theory for Response
Probabilistic Approach
Long Term Values Incorporating:
Wave Spectra
Ship Headings
Service Speed

43. Summary of Criteria Features
Format
Loads
“Net-Ship” Concept
Strength Criteria
Fatigue Criteria
Analysis to Obtain Load Effects

44. Finite Element Analysis (Phase B)
3-Dimensional - Determine Global Loads and Boundary Conditions
2-Dimensional - Determine Local Stress and Deflections
Yielding
Buckling
Fatigue

47. Naval Vessel Rules Derived from Gen Specs and Design Data Sheets
Requires Analysis of Longitudinal Strength using DDS 100 and SPECTRA Program
Requires a FEM Analysis
Uses Prescribed Loads from Traditional Navy Criteria and Specific Design Loads
Concern over Shock Load & Ship Weight

48. High Speed Naval Craft
Based on Design Criteria from NSWC- CD Combat Craft Department and NAVSEA
Determines Loads from Vessel Response to Sea State, Speed and Heading
Calculate local Slam pressures and Slam Moments
Combines Slam Moment with Hull Girder Bending Moments