Section 8 Strengthening for regular discharge by heavy grabs

8.1.1 For bulk carriers where cargoes are regularly discharged by heavy grabs and the thickness of the plating of the hold inner bottom, hopper and transverse bulkhead bottom stool is increased in accordance with the requirements of this Section, the ship will, at the Owner's option, be assigned the notation `strengthened for regular discharge by heavy grabs'.

8.1.2 It should be noted that damage to the plating cannot be excluded even when complying with these requirements and can result from the mishandling of the grabs during the discharge of cargo.

8.1.3 The grab weight given in Pt 3, Ch 9, 8.2 Inner bottom plating 8.2.1 does not preclude the use of heavier grabs. It is intended as an indication to the Builders, Owners and operators of the increased risk of local damage and the possibility of accelerated diminution of the plating thickness if grabs heavier than this are used regularly to discharge cargo.

8.1.4 The maximum unladen weight of the grab is to be recorded in the Loading Manual, see also Pt 3, Ch 4, 8.2 Loading Manual 8.2.4.(e).

8.1.5 The requirements in this Section are not applicable to Double Hull Oil Tankers or Bulk Carriers with a CSR notation. See Pt 1, Ch 2, 2.3 Class notations (hull).

8.2.1 The thickness of the inner bottom plating in the holds is to be not less than required by the greater of the following:

1. 

2. t

   =

   the Rule required thickness, in mm in accordance with Pt 4, Ch 7, 8 Double bottom structure for the intended class notation.

   where

   P	=	specified unladen grab weight for the hold, in tonnes, and is not to be taken as less than 25 tonnes
   s	=	spacing of inner bottom longitudinals, in mm
   k	=	higher tensile steel factor as defined in Pt 3, Ch 2, 1.2 Steel.

8.3.1 The thickness of the sloped bulkhead plating adjacent to the inner bottom knuckle is to be as required by Pt 3, Ch 9, 8.2 Inner bottom plating 8.2.1 but based on the actual spacing of stiffeners. The plating of increased thickness is to extend for a minimum distance corresponding to a vertical height of 1,5 m above the line of the inner bottom. Outboard of the plating of increased thickness, the thickness of the adjacent strakes is to be tapered to the Rule thickness for plating, as required by Pt 4, Ch 1, 8.4 Inner bottom plating and stiffening 8.4.1, at the top corner of the tank, see also Pt 4, Ch 7, 9.2 Sloped bulkhead plating 9.2.3 where, in addition, the `strengthened for heavy cargo notation' is desired.

8.4.1 The thickness of the bulkhead or stool plating adjacent to the inner bottom is to be as required by Pt 3, Ch 9, 8.2 Inner bottom plating 8.2.1 but based on the actual spacing of the bulkhead or stool stiffeners. The plating of increased thickness is to extend for a minimum distance corresponding to a vertical height of 1,5 m above the line of the inner bottom.