Appendix 4

 ADVANCED PROVISIONS AND CONSIDERATIONS APPLICABLE TO SEMI-STANDARDIZED CARGOES

This appendix contains advice that may be considered for the stowage and securing of semi-standardized cargoes in addition to the other provisions of chapter 4, annex 4 and annex 13 of this Code.

The provisions in section 1 below may be used for the following conditions:

• .1 worst case accelerations are used for the design of securing arrangements of semi-standardized cargoes, i.e. the most severe external forces within the particular deck or otherwise defined region of the vessel are applied;

• .2 uniform securing arrangements are used for types of cargo items considering stepped weight classes, whereby arrangements always cover the highest weight within a class and the most unfavourable position of the centre of gravity;

• .3 the range of lashing angles is well defined by the pattern of securing points in the vessel, as well as on vehicles. The assessment uses worst case angles, i.e. the worst combination of vertical and horizontal angles within the given ranges; and

• .4 securing equipment is regularly inspected when used for recurrent application.

 1 Performance factor for short voyages

For cargo securing arrangements considered in section 7.1 case .3 (short duration voyages up to 72 hours), the forces and moments on the right side of the balance equations in section 7.3 may be multiplied by the F_P performance factor of 1.15, as illustrated below:

Transverse sliding: F_y ≤ (μ · m · g + f_y1 · CS₁ + … + f_yn · CS_n)· F_P

Longitudinal sliding: F_x ≤ (μ · (m · g – f_z · F_z) + f_x1 · CS₁ + … + f_xn · CS_n )· F_P

Transverse tipping: F_y · a ≤ (b · m · g + 0.9 · (CS₁ · c₁ + CS₂ · c₂ + … + CS_n · c_n)) · F_P

 2 Asymmetrical securing arrangements

For asymmetrical lashing arrangements and for cargoes resting on supports with different coefficients of friction, separate sliding of the item's fore and aft ends should be considered in the transverse direction. The calculations for each end should be based on the part of the item's weight resting on each support and the characteristics of the cargo securing devices attached to each end.

 3 Safety factor

In the case of elementary securing arrangements, where no more than two devices per impact direction are used and loads are evenly distributed by proper orientation to the centre of gravity of the cargo item, the calculated CS of securing devices may be obtained by:

The specific conditions for the use of the reduced safety factor should be outlined in the ship's Cargo Securing Manual.

 4 Friction coefficients

In addition to the friction coefficients in table 5 in section 7.2, the following friction coefficients (μ) may be applied.

Table 8 – Additional friction coefficients

 5 Effect of parking brake and wheel chocks

For wheel-based cargoes, the effect of parking brakes as well as the effect of wheel chocks may be taken into account when dimensioning securing arrangements against movement in the rolling direction. Usually parking brakes have a braking capacity corresponding to a force equal to 0.2 · g · GVM (kN), where GVM is the gross vehicle mass of the item in tonnes and in most cases the parking brake is applied on one axle only. If a wheel is chocked it can be considered not to roll and the friction in the rolling direction should be taken as the lesser of the friction between the tyre and the ship's deck, and the chock and the ship's deck.