Shipbuilders’ Feedback on IACS Harmonised Common Structural Rules (April Version) China Association of the National Shipbuilding Industry (CANSI) Extract 2: Grab

Contents Technical Issues on CSR-H Consequence Assessment by CANSI Weight Estimation

Technical Issues on CSR-H Vertical acceleration Grab requirement Extent of high tensile steel Shear strength Hull girder ultimate strength Fatigue results

Grab requirement (1/5) For Bulk carriers, the additional class notation GRAB[X] is mandatory for ships having one of the additional service features BC-A or BC-B. The unladen grab weight X is taken not less than: CSR-BCCSR-H (2012.7)CSR-H (2013.2) 20t >70,000DWT40t L>=250m35t 200m<=L<250m30t otherwise20totherwise20t

Grab requirement (2/5) It could be summarized that 5t increasing for unladen grab will induce about 1mm increasing for inner bottom plating, Hopper plate and lower stool plate. L(m)STRUCTURE ITEM CSR-BCCSR-H (2012.7)CSR-H (2013.4) GRAB(t) t net (mm) GRAB(t) t net (mm) GRAB(t) t net (mm) 250m (120K BC and above) Inner bottom plate 25* (normal) Hopper plate Lower stool plate m (70K BC ~120K BC) Inner bottom plate Hopper plate Lower stool plate Note: the spacing is 850mm and the material is HT36

Grab requirement (3/5) Although some reduction from July version to April version, it is still too high. The statistics for the unladen grab weights of Chinese discharge ports is in the process. But it should be pointed out that:  The selection grab is determined by the type of bulks. If unreasonable selection, the efficiency of loading/unloading will decrease.  The type of grabs: Mechanical type Hydraulic type, no need to consider grab falling  The additional class notation does not negate the use of heavier grabs, but the owner and operators are to be made aware of the increased risk of local damage and possible early renewal of inner bottom plating if heavier grabs are used regularly or occasionally to discharge cargo.

Grab requirement (4/5) From 2006 when CSR coming into force, how are the status for those BC with GRAB[20]? If heavy grabs in ports for BCs with lower grab notation:  a suitable grab will be the choice  reasonable loading/unloading sequence not rough operation In ILO code of practice – safety and health in ports, it is said that:  When grabs are used to handle bulk cargo: there should be ample room at loading and unloading points for workers to avoid the swinging grab; if heavy goods such as ore are being handled, special supervision should be provided for trimmers; the attachment and changing of grabs on the lifting appliance should be left to the engineers in charge of the appliance.

Grab requirement (5/5) For Grab requirement, CANSI’s questions are:  The following texts should be added: The additional class notation does not negate the use of heavier grabs, but the owner and operators are to be made aware of the increased risk of local damage and possible early renewal of inner bottom plating if heavier grabs are used regularly or occasionally to discharge cargo.  Is it reasonable for the simplified formula for plating thickness with grab requirement in CSR-H?  How to consider the relationship between the type of bulks and the corresponding grab?  Rules should give the minimum or average safety requirement not the max. requirement. GRAB [25] is acceptable!