INTERNATIONAL MARITIME ORGANIZATION E IMO SUB-COMMITTEE ON SHIP DESIGN AND EQUIPMENT 47th session Agenda item 15 DE 47/INF.10 19 December 2003 ENGLISH ONLY DOUBLE-SIDE SKIN CONSTRUCTION OF BULK CARRIERS Consideration on sufficient strength of double-side skin bulk carriers against flooding accidents Investigation on hull girder strength in flooded condition Submitted by Japan SUMMARY Executive summary: This document provides background information for Japan’s proposal of the amendments of SOLAS Chapter XII Action to be taken: Paragraph Related documents: DE 47/16/1, DE 47/15, DE 47/INF.9 The present regulation in SOLAS Chapter XII requires bulk carriers constructed on or after July 1999 and of 150 m in length and upwards of single-side skin construction designed to carry solid bulk cargoes having a density of 1,000 kg/m3 and above to have sufficient strength to withstand against flooding of any one cargo hold in all loading and ballast conditions, taking into account dynamic effects resulting from the presence of water in the hold, and taking also into account the recommendations adopted by IMO The Maritime Safety Committee, at its seventy-sixth session, agreed to amend SOLAS regulation XII/5 for inclusion of double-side skin bulk carriers In this paper, Japan informs of the results of the investigation of hull girder strength of double-side skin bulk carriers in hold flooded condition induced by side damage which has been assumed as a worst scenario taking account of: the suggestion by the United Kingdom at MSC 76, that hold flooding due to collision might not be properly prevented by double-side skin construction; and the results of a Japanese study submitted by a separate paper (DE 47/INF.9) to this session of the Sub-Committee, that hold flooding caused by collision will become the most important scenario in terms of the magnitude of risk to double side skin bulk carriers For reasons of economy, this document is printed in a limited number Delegates are kindly asked to bring their copies to meetings and not to request additional copies I:\DE\47\INF.10.DOC DE 47/INF.10 -2- This change of accident scenario for cargo hold flooding shall be reflected in new SOLAS chapter XII not only of assumed flooding compartments related to the still water bending moment but also the assumed sea conditions for the actual wave bending moment, as suggested in the proposal by Japan in DE 47/15, that 70% of wave bending moment for intact condition is appropriate for damaged condition If new SOLAS chapter XII is modified properly, the hull girder strength of double side skin bulk carrier is at least equivalent to or stronger than that of single side skin bulk carriers The detailed discussion on the comparison of the strength is described in the attached in the annex Action requested of the Sub-Committee The Sub-Committee is invited to note the above information and take action as appropriate *** I:\DE\47\INF.10.DOC DE 47/INF.10 ANNEX COMPARISON OF BENDING MOMENT AFTER FLOODING BETWEEN DSS BC AND SSS BC The hull girder bending moment of a double-side skin bulk carrier after flooding was investigated comparing that of the same size of single-side skin bulk carrier Three kinds of sizes, i.e Capesize, Panamax and Handysize, are selected At this moment a typical design of a double-side skin bulk carrier is not available Therefore, the flooding condition due to collision of a double-side skin bulk carrier was hypothetically substituted by the flooding condition of single-skin bulk carrier where not only a cargo hold (CH) but also the adjacent ballast tanks such as double bottom tank (DBT), bilge hopper tank (BHT) and top side tank (TST) are flooded (see Figure 1) The flooding condition of a single-side skin bulk carriers corresponds to only one cargo hold flooding according to the present SOLAS chapter XII The results are shown in the following tables The hull girder bending moment of Capesize DSS bulk carrier increase some 15% of the wave bending moment, Mw, comparing the same size of SSS bulk carrier In case of Panamax bulk carriers it would increase some 10% And in case of Handysize bulk carriers, it would increase some 15% The present regulation of SOLAS chapter XII requires 80% of Mw to single-side skin When the new regulation of SOLAS chapter XII requires 70% of Mw to double-side skin according to the most probable flooding scenarios, the hull girder strength of DSS bulk carrier would increase slightly The results are summarized in the Table It other words, the survivability of DSS bulk carrier against hold flooding would be at least equivalent to that of the present SSS bulk carriers Figure Image of hold flooded condition of SSS BC, flooded condition of DSS BC and its substitutive condition using SSS BC Table Comparison of hull girder strength of DSS BC with the present SSS BC Size Results Cape : Required bending moment, still water bending moment (hereinafter, referred to Size as ‘SWBM’) in case of CH+TST+BHT+DBT flooded + 70% of Mw 0.7, is larger by some 5% than the present required value, CH flooding + 80% of Mw As a result hull girder strength would increase 2% or 3% Panamax : Almost same to the present Handy : Required bending moment, SWBM in case of CH+TST+BHT+DBT flooded + 70% of Mw 0.7, is larger by some 5% than the present required value, CH flooded + 80% of Mw As a result hull girder strength would increase 2% or 3% I:\DE\47\INF.10.DOC DE 47/INF.10 ANNEX Page Result of Calculation - Cape Size BC Table C1 Cape Size Single Side Skin SWBM of Single SS BC with hold flooded SWBM of Single SS BC with hold + TST/BHT/DBT flooded Wave Induced BM (WIBM) Total BM (SWBMd + WIBM) Increase of BM with DDS flooded (SWMBd - SWMBs) (SWMBd - SWMBs) / WIBM SWBMs Hog SWBMs Sag SWBMd Hog SWBMd Sag WIB Hog WIB Sag BMt Hog BMt Sag ex BM Hog ex BM Sag ex Rate Hog ex Rate Sag Table C2 Cape Size Single Side Skin SWBM of Single SS BC with hold flooded SWBM of Single SS BC with hold + TST/BHT/DBT flooded Wave Induced BM (WIBM) Total BM (SWBMd + WIBM) Increase of BM with DDS flooded (SWMBd - SWMBs) (SWMBd - SWMBs) / WIBM SWBMs Hog SWBMs Sag SWBMd Hog SWBMd Sag WIB Hog WIB Sag BMt Hog BMt Sag ex BM Hog ex BM Sag ex Rate Hog ex Rate Sag Table C3 Cape Size Single Side Skin SWBM of Single SS BC with hold flooded SWBM of Single SS BC with hold + TST/BHT/DBT flooded Wave Induced BM (WIBM) Total BM (SWBMd + WIBM) Increase of BM with DDS flooded (SWMBd - SWMBs) (SWMBd - SWMBs) / WIBM I:\DE\47\INF.10.DOC SWBMs Hog SWBMs Sag SWBMd Hog SWBMd Sag WIB Hog WIB Sag BMt Hog BMt Sag ex BM Hog ex BM Sag ex Rate Hog ex Rate Sag L= B= Alternate 4,467,984 -3,885,869 4,860,423 -4,913,819 6,346,214 -6,699,872 11,206,637 -11,613,691 392,439 -1,027,950 6% 15% 280.00 47.00 Homogeneous -6,816,106 -7,781,155 6,346,214 -6,699,872 6,346,214 -14,481,027 -965,049 0% 14% L= B= Alternate 4,861,500 280.00 45.00 Homogeneous -5,483,800 5,194,200 6,037,700 -6,316,300 11,231,900 -6,428,400 6,037,700 -6,316,300 -12,744,700 332,700 -944,600 6% 15% L= B= Alternate 4,863,299 -3,239,498 5,397,409 -4,155,670 6,346,214 -6,699,872 11,743,623 -10,855,542 534,110 -916,172 8% 14% 279.00 45.00 Homogeneous -4,676,795 -5,589,332 5,990,643 -6,255,623 5,990,643 -11,844,955 -912,537 0% 15% DE 47/INF.10 ANNEX Page Result of Calculation - Panamax BC Table P1 Panamax Size Single Side Skin SWBM of Single SS BC with hold flooded SWBM of Single SS BC with hold + TST/BHT/DBT flooded Wave Induced BM (WIBM) Total BM (SWBMd + WIBM) Increase of BM with DDS flooded (SWMBd - SWMBs) (SWMBd - SWMBs) / WIBM SWBMs Hog SWBMs Sag SWBMd Hog SWBMd Sag WIB Hog WIB Sag BMt Hog BMt Sag ex BM Hog ex BM Sag ex Rate Hog ex Rate Sag L= B= Alternate 3,276,079 3,457,132 2,425,942 -2,561,134 5,883,074 -2,561,134 181,053 7% 0% 215.50 32.26 Homogeneous 1,655,565 -1,594,959 1,860,349 -1,843,328 2,425,942 -2,561,134 4,286,291 -4,404,462 204,784 -248,369 8% 10% SWBMs Hog SWBMs Sag SWBMd Hog SWBMd Sag WIB Hog WIB Sag BMt Hog BMt Sag ex BM Hog ex BM Sag ex Rate Hog ex Rate Sag L= B= Alternate 2,486,707 -1,093,815 2,723,060 -1,206,708 2,434,312 -2,540,115 5,157,372 -3,746,823 236,353 -112,893 10% 4% 217.00 32.26 Homogeneous 1,475,650 -1,827,652 1,718,496 -2,120,588 2,434,312 -2,540,115 4,152,808 -4,660,703 242,846 -292,936 10% 12% Table P2 Panamax Size Single Side Skin SWBM of Single SS BC with hold flooded SWBM of Single SS BC with hold + TST/BHT/DBT flooded Wave Induced BM (WIBM) Total BM (SWBMd + WIBM) Increase of BM with DDS flooded (SWMBd - SWMBs) (SWMBd - SWMBs) / WIBM I:\DE\47\INF.10.DOC DE 47/INF.10 ANNEX Page Result of Calculation - Handy Size BC Table H1 Handy Size Single Side Skin SWBM of Single SS BC with hold flooded SWBM of Single SS BC with hold + TST/BHT/DBT flooded Wave Induced BM (WIBM) Total BM (SWBMd + WIBM) Increase of BM with DDS flooded (SWMBd - SWMBs) (SWMBd - SWMBs) / WIBM SWBMs Hog SWBMs Sag SWBMd Hog SWBMd Sag WIB Hog WIB Sag BMt Hog BMt Sag ex BM Hog ex BM Sag ex Rate Hog ex Rate Sag L= B= Alternate 1,891,081 -835,215 2,101,137 -943,725 1,542,800 -1,640,200 3,643,937 -2,583,925 210,056 -108,510 14% 7% 181.00 32.20 Homogeneous 753,162 -1,587,795 997,656 -1,750,785 1,542,800 -1,640,200 2,540,456 -3,390,985 244,494 -162,990 16% 10% SWBMs Hog SWBMs Sag SWBMd Hog SWBMd Sag WIB Hog WIB Sag BMt Hog BMt Sag ex BM Hog ex BM Sag ex Rate Hog ex Rate Sag L= B= Alternate 1,609,252 1,828,110 1,509,870 -1,632,271 3,337,980 -1,632,271 218,858 14% 0% 180.00 32.20 Homogeneous -1,509,112 -1,652,004 1,509,870 -1,632,271 1,509,870 -3,284,275 -142,892 0% 9% Table H2 Handy Size Single Side Skin SWBM of Single SS BC with hold flooded SWBM of Single SS BC with hold + TST/BHT/DBT flooded Wave Induced BM (WIBM) Total BM (SWBMd + WIBM) Increase of BM with DDS flooded (SWMBd - SWMBs) (SWMBd - SWMBs) / WIBM _ I:\DE\47\INF.10.DOC ... same size of single -side skin bulk carrier Three kinds of sizes, i.e Capesize, Panamax and Handysize, are selected At this moment a typical design of a double- side skin bulk carrier is not available... the flooding condition due to collision of a double- side skin bulk carrier was hypothetically substituted by the flooding condition of single -skin bulk carrier where not only a cargo hold (CH)... girder bending moment of Capesize DSS bulk carrier increase some 15% of the wave bending moment, Mw, comparing the same size of SSS bulk carrier In case of Panamax bulk carriers it would increase