Harmonization of Subdivision & Damage Stability Regulations in SOLAS Chapter II-1

1. Harmonization of Subdivision & Damage Stability Regulations in SOLAS Chapter II-1 Robert Tagg • Herbert Software Solutions, Inc. James Person • U.S. Coast Guard (G-MSE-2) Chesapeake Section SNAME

2. Harmonization of Subdivision & Damage Stability Regulations • Historical Background & Introduction to Probabilistic Damage Stability Regs • SLF 46 • SDS Correspondence Group • MSC 78 Decisions • SLF 47 Outcome • The Way Ahead Chesapeake Section SNAME

3. Historical Background • 1854 – British Maritime Shipping Act • 1891 – British Board of Trade (2-compt. Std.) • 1895 – German 2-compt. Standard • 1912 – Titanic casualty • 1914 – First SOLAS Conference • 1929 – SOLAS, “Criterion of Service” • 1948 – SOLAS, damage stability added • 1956 – Andrea Doria casualty, IMCO established • 1960 – SOLAS, acknowledged deficiencies Chesapeake Section SNAME

4. Historical Background (cont.) • 1966 – Loadline Convention (B-60, B-100) • 1971 – Tory Canyon casualty, USCG 2-compt. for tankers – MARPOL ‘73 • 1974 – 1st Probabilistic Standard, A.265 • 1975 – MARPOL for chemical and gas carriers • 1988 – Probabilistic rules for dry cargo ships • 1990 – SOLAS, Herald of Free Enterprise Chesapeake Section SNAME

5. Introduction to Probabilistic Regulations • Weaknesses in Criterion of Service, Floodable Length, and 2-compt. standard approach • The Fundamental Fallacy • Wendel and the probabilistic framework • Probability of damage size and location • Probability of ship condition (draft and permeability) • Probability of seastate at time of casualty • Probability of survival after flooding Chesapeake Section SNAME

6. The Fundamental Fallacy Chesapeake Section SNAME

7. Development of Probabilistic Standards • Damage statistics (Damage Cards) • Damage sizes and locations • Seastate at time of casualty Chesapeake Section SNAME

8. Development of Probabilistic Standards • Survivability Model Tests • Capsize mechanisms • Level of stability required to survive specific seastates Chesapeake Section SNAME

9. Application of Probabilistic Standards • Find all possible combinations of damaged compartments • Determine probability of occurrence for each damage • Calculate the probability of survival for each damage • Sum all successful cases to yield overall attained probability of survival - A • Compare with required probability of survival - R Chesapeake Section SNAME

10. History of Probabilistic Damage Stability Regulations • 1973 – A.265 Passenger Ship • 1992 – SOLAS B-1 Cargo Ship • 1993 – SLF begins Damage Stability Harmonization effort • 2000-2003 – EU HARDER Project • 2003 – SLF 46 • 2004 – SLF 47 Chesapeake Section SNAME

11. Overview – Project HARDER • March 2000, a 4.5M€ 3-year project • 19 organizations from industry and academia • Systematically investigate the validity, robustness, consistency and impact • Develop new harmonized damage stability regulations for consideration at IMO Chesapeake Section SNAME

12. SLF 46 • Considered HARDER Project results & proposals • Majority accepted subject to some further validation • Single “R” for all dry cargo ship types • Downward trend of survivability for larger passenger ships was unacceptable; the trend should be upwards for larger ships and for ships with greater numbers of passengers • Requested guidance from MSC on the “equivalent level of safety” conflict • Established the SDS Correspondence Group Chesapeake Section SNAME

13. Survivability of Passenger Ships – Downward Trend Chesapeake Section SNAME

14. SDS Correspondence Group – Terms of Reference • Coordinate validation of sample ship calculations regarding: • p-factor; • SEM method & possible introduction of an Hmin factor; • transient & intermediate stages of flooding/equalization; • minimum values of the index A at specific draughts; • required index R; • passenger heel and wind moments; and • investigate the impact of the proposal on the design of ships, in particular large passenger ships • Finalize the draft revised SOLAS Chapter II-1 Chesapeake Section SNAME

15. SDS Correspondence Group – Actions • Initial task – validate and finalize the calculation methodology • various studies, analyses, proposals, etc. • an intersessional meeting in Malmö, Sweden • Questionnaire voting • Summary of results in SLF 47/3/2 Chesapeake Section SNAME

16. SDS Correspondence Group – Actions • Re-calculation of sample ships using agreed formulas from Questionnaire results • Major formula changes for passenger ships – necessary to recalculate all passenger ships • Minor formula change for cargo ships – not necessary to recalculate all cargo ships • 52 sample ship calculations conducted • 32 passenger ships and 20 cargo ships • Analyses for “R” conducted by NTUA • Summary of results in SLF 47/3/3 Chesapeake Section SNAME

17. SDS Correspondence Group – Actions • Revised SOLAS Chapter II-1 Parts A, B and B-1 • reviewed and updated draft text • submitted version in SLF 47/3/1 • Proposals for “R” and minimum values of “A” • no exact consensus for “R”, but general support for “R” proposals • no exact consensus on minimum values of “A” but general support for min “A” proposals • summary of results in SLF 47/3/8 Chesapeake Section SNAME

18. MSC 78 Decisions – Confirmed SLF 46 opinions • Same survivability standard “R” for all dry cargo ship types • even if ro-ros must meet a higher standard • Survivability standard “R” for passenger ships should increase with ship size and number of persons onboard • even if this means exceeding current SOLAS • Complete harmonization task – finalize revised SOLAS Chapter II-1 for approval at MSC 79 Chesapeake Section SNAME

19. SLF 47 Outcome – Initial decisions in plenary • majority opinion that the proposed harmonized subdivision and damage stability regulations were a technically sound standard and that they should be finalized at SLF 47 • Italy strongly opposed – they want to delay to allow further validation work (specifically the “p” and “s” factors for large passenger ships) • agreed to delete inclusion of SEM method in “s” factor because effects of water on deck already adequately accounted for Chesapeake Section SNAME

20. SLF 47 Outcome – SDS Working Group actions • Reg 7-1 “p” factor • Due to alternate proposal by Italy, damage distributions and statistical analyses for “p” factor were reviewed • General majority view that “p” factor in draft reg 7-1 was as accurate and correct as could be expected from the available collision damage statistics Chesapeake Section SNAME

21. SLF 47 Outcome – SDS Working Group actions • Reg 7-2 “s” factor • based on residual GZ, range, and heel angle • intermediate stage flooding criteria only for passenger ships (similar to current SOLAS) • additional heeling moments applied only to passenger ships (similar to current SOLAS) • SEM method dropped Chesapeake Section SNAME

22. SLF 47 Outcome – SDS Working Group actions • Reg 6 Required Subdivision Index “R” • Passenger ships • considered sample ship calculation results and methodology used to develop “R” • considered alternate proposal by ICCL (with standard deviation) • agreed to Correspondence Group proposal for “R” • Added new minimum partial “A” requirement (0.9R) at each partial draft Chesapeake Section SNAME

23. SLF 47 Outcome – SDS Working Group actions Chesapeake Section SNAME

24. SLF 47 Outcome – SDS Working Group actions • Reg 6 Required Subdivision Index “R” • Cargo ships • considered sample ship calculation results • agreed to Correspondence Group proposal for “R”, except for small ships less than 100m • for ships less than 100m, knuckle point and lower “R” line similar to current Part B-1 • Added new minimum partial “A” requirement (0.5R) at each partial draft Chesapeake Section SNAME

25. SLF 47 Outcome – SDS Working Group actions Chesapeake Section SNAME

26. SLF 47 Outcome – SDS Working Group actions • Reg 9 Double Bottoms • Harmonized for passenger & cargo ships • DB height = B/20 (min 0.76m & max 2.0m) • If full DB not fitted, then must comply with bottom damage survivability standard • Current passenger ship DB length applicability limits deleted Chesapeake Section SNAME

27. SLF 47 Outcome – Final action • SLF agreed to the draft revised SOLAS Chapter II-1 Parts A, B and B-1 for submission to MSC 79 for approval with a view to adoption • Italy reserved its position (with several others) & intends to submit a proposal to modify the Chapter II-1 draft text directly to MSC 80 for consideration Chesapeake Section SNAME

28. The Way Ahead • MSC 79 – December 2004 • considered for approval • IMO procedural issue: 6 month interval between approval and adoption; Germany & Denmark sponsored IMO Adoption Circular Ltr • MSC 80 – May 2005 • considered for adoption • Into force date (1 January 2007?) Chesapeake Section SNAME