Adopted by IACS Council on 14 December 2005 Summary of CSR – Tanker Rules – Bulk Carrier Rules Harmonization Maintenance Common Structural Rules for Tankers and Bulk Carriers

IACS Common Structural Rules 2 Summary of CSRs “Common Structural Rules for Double Hull Oil Tankers” “IACS Common Structural Rules for Bulk Carriers”

IACS Common Structural Rules 3 Summary of CSRs Jun Jan st Draft available to Public 2 nd Draft available to Public 30 Sep 2005 Apr 2005 Publish 15 Jan 2006 CSR Effective 1 Apr 2006 CSR Adopted 1 Jan 2006 Industry comments 6 months Industry comments 5 months

IACS Common Structural Rules 4 CSR Tankers

IACS Common Structural Rules 5 CSR Tankers SectionTopic Introduction Underlying Principles Rules Applications Basic Information Structural Arrangement Material and Welding Loads Scantling Requirements SectionTopic A B C D Design Verification Buckling and Ultimate- Strength General Requirements Renewal Criteria (SiO) Hull Girder Ultimate Strength Structural Strength Assessment Fatigue Strength Assessment Buckling Strength Assessment

IACS Common Structural Rules 6 CSR Tankers 1st hearing (Jun ~ Dec 2004) – 2834 comments received during hearing period – 988 (35%) of which resulted in either editorial or rule changes – 197 of which are noted for future development 2nd hearing (Apr ~ Sep 2005) – 228 comments received during hearing period – 76 (33%) of which resulted in either editorial or rule changes – 12 of which are noted for future development 2005 feedback from industry meetings with designers, shipyards and shipowner groups – Japan (3 visits in 2005) – Korea (2 visits in 2005) – China (1 visit in 2005) – Shipowner groups (5 visits in 2005)

IACS Common Structural Rules 7 CSR Tankers – Summary of Industry Feedback a) General scantling increase - Feedback received that the general scantling increase needs justification and is not supported by damage records Rule change: Criteria reviewed and increase of some of the allowable stresses for plate and stiffener requirements by 5-7% found justified. b) Large localised increases from FE buckling - 2nd draft JTP Rules require some areas where net scantlings are significantly above the as-built scantlings of present fleet. Typically buckling assessment for FE caused the increase. Rule change: FE procedure revised to take into account combined probability of cargo density, loading pattern and dynamic load level by introducing a correction factor applied on the cargo pressure for the extreme dynamic load combination. c) Too many load cases - the number of FE load cases to be assessed makes assessment very labour intensive Rule change: almost halved the number of load cases by removing cases which do not govern scantlings.

IACS Common Structural Rules 8 CSR Tankers – Summary of Industry Feedback d) Corrosion margins - corrosion margins are too small for a design life of 25 years and will lead to a significant amount of steel replacement. Rule change: upward adjustments made to the average and local (pitting, edge and groove) corrosion. e) Coating performance standard - lack of a minimum performance standard for coating leads to large variation in application and actual coating life. The coating of some ships is so poor that compete renewal by sandblasting and re-coating is needed after a few years. Rule change: IACS agreed to include a requirement for a minimum performance standard in the common structural Rules by reference to SOLAS upcoming regulation. f) Grinding - allowance for grinding as a measure for increasing the fatigue life was questioned. Rule change: Rules modified to be more specific on where credit may be given for grinding. Detailed requirements introduced on what is required for the grinding procedure.

IACS Common Structural Rules 9 CSR Tankers – Summary of Industry Feedback g) Fatigue – the fatigue design standard of 25 year operation in North Atlantic wave environment is too severe taking into account the typical operation of the majority of tankers. The criteria in principle disallows designs with material of HT36 in deck. Reply: As the 25 NA design standard is given in the draft IMO Goal Based Standard the project has decided not to make any amendments to the fatigue target. h) Hull girder ultimate strength – the hull girder ULS requirement in the second draft is too severe and some existing vessels will not pass even in the as-built condition. Use of material of HT36 is needed for compliance but contradicts the fatigue criteria. Reply: Studies performed during the Rule development did not support changes to the requirement. i) IACS recommendation 47 Shipbuilding and Repair Quality Standard - the IACS recommendation is not up to date and may cause conflicts with commonly used national standards. Reply: The comment has been forwarded to IACS Survey Panel. The Rules have been updated to make it clear that acceptable national standards are allowed. Rec. 47 is used as common reference document for strength assessment.

IACS Common Structural Rules 10 CSR Tankers – Summary of Industry Feedback j) Delete primary support member prescriptive rules – the prescriptive requirements for PSM are not needed since the members are checked with FEM. Reply: PMS requirements have been retained to have a consistent application of requirements, a solid baseline minimum strength level, and to “catch” limitations in the FE analysis such as limited quantity of loading cases/conditions and assumptions for boundary conditions. To account for differences between the two methods, the Rules permit scantlings to be reduced to 85% of the prescriptive requirements where the FE results demonstrate that reduction is acceptable. k) Demonstrate link between damages and scantling increases – there is no need for the scantling increase if there is no damage. Reply: CSR was not developed as a response to damages on existing vessels. Scantling increases will result from increasing the design basis.

IACS Common Structural Rules 11 CSR Tankers – Summary of Industry Feedback l) Rolling tolerances - the under tolerances are eating into the wastage allowance and should not be accepted. UGS also commented on lack of specified procedures/locations for performing thickness measurements. Reply: Question/issue is under review by IACS. m) Approval of national fabrication standards - UGS raised concern over approval of national fabrication standards on a class by class basis without common procedures for the approval of such Reply: The request is under review by IACS.

IACS Common Structural Rules 12 CSR Bulk Carriers

IACS Common Structural Rules 13 CSR Bulk Carriers : Table of Contents Ch 1. General principles Ch 2. General arrangement design Ch 3. Structural design principles Ch 4. Design loads Ch 5. Hull girder strength Ch 6. Hull scantlings Ch 7. Direct strength analysis Ch 8. Fatigue check of structural details Ch 9. Other structures Ch 10. Hull outfitting Ch 11. Construction and testing Ch 12. GRAB additional notation Ch 13. Maintenance of Class & Thickness measurements

IACS Common Structural Rules 14 CSR Bulk Carriers 1st hearing (Jun ~ Dec 2004) – About 3000 comments received during hearing period – 17 major modifications in the Rules and re- writing of Chapters 7(Direct Strength Analysis), 8 (Fatigue), 11 (Construction) and 12 (Ships in Service) – Modifications issued in 2 nd Draft 2nd hearing (Apr ~ Sep 2005) – About 1000 comments received during hearing period – 16 major modifications in the Rules – Modifications issued in Final Draft

IACS Common Structural Rules 15 MAJOR MODIFICATIONS OF BULK CARRIERS RULES AFTER THE FIRST DRAFT – Larger uniform corrosion wastage allowances for transverse bulkheads, side shell in line with 95% probability of non-exceedance (instead of 90%) – Thickness rounding procedure is modified, due to harmonisation between JTP and JBP – Harmonisation of ships in service requirements between JTP and JBP – Rewritten FEM procedure: Finite element models are now only three holds models, with modified boundary conditions to provide same results between direct and superposition methods – Reduction of the number of loading cases to be considered in Direct strength analysis – Compliance with new SOLAS requirements for flooding of DSS bulk carriers – Quartering sea loading for cross-deck structure, further to harmonisation between JTP and JBP – Mandatory GRAB notation for grab loading and steel coil requirements

IACS Common Structural Rules 16 CSR Bulk Carriers – Summary of Industry Feedback a) Mandatory grab notation – In order to protect the inner bottom against cargo damages, grab notation has been made mandatory (Ship owners comment) b) Increase in values of corrosion additions – Wastage allowances have been increased by 1 mm to 2 mm compared to first draft. Higher increases concern heated HFO tanks, transverse bulkheads and Side shell wind & water strake (Ship owners comment) c) Modifications of prescriptive requirements in Ch 3 Sec 6 & Ch 9 Sec 1 & 2 – Continuity of strength within primary members (from cargo area to engine room and fore/aft parts) has been put to the top level and the text modified to avoid vague expressions (UGS comment). Prescriptive requirements concerning spacing of primary members have been modified to suit successful recent designs (Shipyards comments) d) Prescriptive requirements for bulkheads - Prescriptive requirements for transverse bulkheads in way of ballast holds of ships smaller than 150 m in length have been added (Ship owners comments) e) Number of loading conditions for Direct Strength Analyses – the number of cases to be computed has been divided by a factor 2 to consider only the cases having practical influence on the design (Shipyards comments) f) Buckling procedure – the buckling requirements have been rewritten to be more explicit and easy to apply ( Shipyards comments)

IACS Common Structural Rules 17 CSR Bulk Carriers – Summary of Industry Feedback g)Relative deflection criteria – Relative deflection criteria between the double bottom and the transverse bulkheads has been added to cope with UGS concerns about flexible D/B structure (Ship owners comment) h)Permissible misalignments – Values of IACS Rec. 47 for permissible misalignments of some important structural details have been included in the rules as minimum requirements (Ship owners comment) i)Minimum thickness– Minimum thickness of weather deck has been found too conservative and aligned on Oil Tankers CSR and inner side of DSS bulk carriers has been reduced to be not greater than side shell (Shipyards comments) j)Requirements for pillars - Prescriptive requirements for pillars have been added and fillet weld accepted in compression only (Shipyards comments) k)Deep penetration welding – The number of details where deep penetration welding is requested has been increased (Class comments) l) Scantling pressure for hatch covers in ballast holds – the pressure has been reduced to take into account ullage effect ( Manufacturers comments) m) Prescriptive coating performance standard – Lack of requirements in this case may lead to poor standards applied in practice therefore this new item has been introduced in the Rules (Shipowners comment)

IACS Common Structural Rules 18 CSR Bulk Carriers – Summary of Industry Feedback n) Provide mandatory prescriptive requirements for the spacing/scantlings of all primary members– Direct strength analysis ( stresses + buckling + deflections) is fundamentally trusted for scantlings of primary members in line with modern practices (Ship owners comment) o) Request complete ship extent FEM model - results of 3 holds models in the cargo area may be extrapolated to fore/aft regions (Ship owners comments) p) Increases of corrosion allowances not connected to IACS statistics – partially accepted for areas where some damages could be omitted from the statistics (voluntary grounding, contact damages on side shell) but not in general, as corrosion allowances are based on IACS statistics ( Ship owners comments) q) Reduce mini thickness of longitudinals – reducing mini thickness of longitudinals to fit present practices was refused due to increase of corrosion allowances (Shipyards comments) r) FEM analyses and fatigue procedure lead to unreasonable increases of scantlings – These increases are justified by excessive spacing of primary members. FEM analysis is effective to detect this problem. Fatigue results are backed by real damage cases (Shipyards comments)

IACS Common Structural Rules 19 Modifications between the third and final drafts Corrosion allowance change limit length is returned back to 150 m – IACS statistics show a difference of corrosion between Handymax and Handysize on one side, Panamax and Capesize of the other side. The limit is 50,000 dwt, corresponding approximately to 190 m in length – While the limit of 190 m is technically justified, an additional wastage margin was provided in 1 st and 2 nd drafts for vessels greater or equal to 150 m in length. The length limit of 150 m was maintained in the Rules. CSR notation is introduced for vessels complying with new Rules – This will allow easy identification of ships built according to the new Common Structural Rules for Oil Tankers and Bulk Carriers

IACS Common Structural Rules 20 Harmonization and Maintenance

IACS Common Structural Rules 21 Short-term harmonization Short-term harmonization issues identified as barriers to adoption have been concluded. – Corrosion additions – Rounding – Wave loads (quartering sea, H.G. shear) – Hull Girder Ultimate Strength – Buckling (prescriptive buckling) – Finite element analysis (two methods in JBP)

IACS Common Structural Rules 22 Long-term harmonization Full harmonization required for – Wave loads – Fatigue – Finite element analysis – Buckling – Prescriptive requirements

IACS Common Structural Rules 23 Long-term harmonization Full Harmonization Plan One year application and feedback period before long term harmonization Detail plan for full harmonization will be developed by the Hull Panel by the end of the one-year feedback period Three years of harmonization work One year for implementation (industry review) Full harmonization in five years from implementation

IACS Common Structural Rules 24 Maintenance of the Rules Common interpretations Feedback from Members and Industry Future amendments to CSR

IACS Common Structural Rules 25 Maintenance of the Rules Groups involved in the rule maintenance – Permanent Secretariat – GPG – Hull Panel – Tanker and Bulk Carrier Project Teams – Project Teams for Cross-checking FE and Prescriptive Requirements

IACS Common Structural Rules 26 Maintenance of the Rules Permanent Secretariat Coordinates the feedback, interpretation and amendment processes and maintains master copy of the rules GPG Provides oversight for the feedback, interpretation and amendment processes and deals with policy matters Hull Panel Is responsible for consistent implementation through common interpretations, consistent replies, and future amendments Tanker and Bulk Carrier Teams Provide technical expertise and prepare replies and interpretations for Members

IACS Common Structural Rules 27 Maintenance of the Rules Additional Project Teams to prepare for consistent implementation of CSR FEA team cross-checking FE requirements Prescriptive Rule team for cross-checking prescriptive requirements Teams will provide benchmark data for software testing to ensure common application and implementation

IACS Common Structural Rules 28 Features of the Common Structural Rules Some of the new features in the CSRs include : Rounding Net thickness Hull girder ultimate strength Coating performance standard

IACS Common Structural Rules 29 Feature – Rounding Round UP to next 0.5mm on wastage allowance Example: twas = 2.5mm from rounding up = 1.0(side1)+1.2(side2) Round TO nearest 0.5 mm on net thickness Example: tnet = 15.5mm from rounding Add the two rounded numbers and the reserve addition to give the gross thickness: tgross = = 18.5 mm

IACS Common Structural Rules 30 Feature – Net Scantling Approach Predicted corrosion in 2.5 years (0.5 mm) Required Net Thickness Corrosion Addition Design Required Renewal Thickness Wastage Allowance In Service Annual Thickness Measurements

IACS Common Structural Rules 31 Feature – Tanker Sample Wastage Allowance Values

IACS Common Structural Rules 32 Inner bottom: 5.5mm Internal member: 3.0mm Bulkhead : 6.5mm Slant of Lower Stool: 6.5mm (void) Inner skin : 4.0mm Hopper Slant: 5.5mm Side shell: S/H: 3.5mm 4.0 mm (wind&water) D/H: 3.0mm 3.5mm (wind&water) Within 3.0m below the top of tank Upper Deck: 4.0mm Sheer strake: 3.5mm Feature – Sample Wastage Allowance Values for BC-A and BC-B Bulk Carriers with L > 150 m Slant : 3.5mm Deck iwo Tr. upper stool (Void) : 3.0mm Bilge strake: 3.0mm Bottom: 3.0mmKeel: 3.0mm Internal member: 3.0mm Slant : 4.0mm Internal member: 4.0mm Face of PSM: 4.5mm Hatch coaming: 3.5mm Face of PSM: 3.5mm Slant of stool: 4.0 mm Upper bracket: 4.5 mm Side frames:4.5 mm Lower bracket: 5.0 mm Bulkhead (Upper): 5.5mm Water Ballast

IACS Common Structural Rules 33 Inner bottom: 4.5mm Internal member: 3.0mm Bulkhead : 3.5 mm Slant of Lower Stool: 4.0mm (void) Inner skin : 3.0mm Hopper Slant: 4.5mm Side shell: SH: 3.0mm 3.5mm (wind&water) DH: 3.0mm 3.5mm (wind&water) Within 3.0m below the top of tank Upper Deck: 4.0mm Sheer strake: 3.5mm Feature – Sample Wastage Allowance Values for BC-C or Bulk Carriers with L < 150 m Slant : 3.0mm Deck iwo Tr. upper stool (Void) : 3.0mm Bilge strake: 3.0mm Bottom: 3.0mmKeel: 3.0mm Internal member: 3.0mm Slant : 3.5mm Internal member: 4.0mm Face of PSM: 4.5mm Hatch coaming: 2.5mm Face of PSM: 3.5mm Slant of stool: 3.0 mm Upper bracket: 2.5 mm Side frames:3.0 mm Lower bracket: 3.0 mm Bulkhead (Upper): 2.5mm Water Ballast

IACS Common Structural Rules 34 Feature – Hull girder ultimate strength Harmonised design criteria JBP ultimate capacity method is included in the JTP Rules With full load homogeneous still water moment: With permissible still water moment:

IACS Common Structural Rules 35 Feature – Coating performance standard For ships contracted for construction on or after the date of IMO adoption of the amended SOLAS Regulation II-1/3-2, by which an IMO “Performance standard for protective coatings for ballast tanks and void spaces” will be made mandatory, the coatings of internal spaces subject to the amended SOLAS Regulation are to satisfy the requirements of the IMO performance standard. Consistent with IMO Resolution A.798(19) and IACS UI SC 122, the selection of the coating system, including coating selection, specification, and inspection plan, are to be agreed between the shipbuilder, coating system supplier and the owner, in consultation with the Classification Society, prior to commencement of construction. The specification for the coating system for these spaces is to be documented and this documentation is to be verified by the Classification Society and is to be in full compliance with the coating performance standard. The shipbuilder is to demonstrate that the selected coating system with associated surface preparation and application methods is compatible with the manufacturing processes and methods. The shipbuilder is to demonstrate that the coating inspectors have proper qualification as required by the IMO standard. The attending surveyor of the Classification Society will not verify the application of the coatings but will review the reports of the coating inspectors to verify that the specified shipyard coating procedures have been followed.

IACS Common Structural Rules 36 IMO Coating Performance Standards (CPS) Earliest Implementation Schedule for SOLAS and IACS CSR Revised SOLAS II-1/3-2 entry into force mandating CPS for ships with keel laid on/after 01 Jul 08 Draft CPS (DE 49) SOLAS XII/6.3 enters into force recommending CPS for Bulk Carriers Approval of CPS and SOLAS II-1/3-2 (MSC 81) Adoption of CPS and Revised SOLAS II-1/3-2 (MSC 82) IACS CSR requires CPS for ships contracted for construction on/after the adoption date of the Revised SOLAS II-1/ (Jan) 2006 (Jan) 2008 (Jan)