The ‘Code’ in this Section refers to IMO Resolution A.715(17) – Code of Safe Practice for Ships Carrying Timber Deck Cargoes, 1991.
1.1 The stowage practices described in this appendix have been found to achieve satisfactory results, provided that account is taken of the recommendations of the Chapters 1-6 of the Code of Safe Practice for Ships Carrying Timber Deck Cargoes, 1991. Although specific conditions may dictate a departure from these guidelines, the basic principles as detailed in 1.2 below should nevertheless be adhered to.
1.2 The basic principle for the safe carriage of timber deck cargo is, as indicated earlier, to make the stow as solid and compact as practicable. The purpose of this is to:
- Prevent slack in the stow which could cause the lashings to slacken;
- Produce a binding effect within the stow; and
- Reduce to a minimum the permeability of the stow.
1.3 Lashings prevent deck cargo from shifting by increasing the friction due to pre-stress forces and counteracting forces on the stow in the direction of possible shifting. The lashings should meet the following criteria:
- The strength of all lashing elements should be at least equal to that recommended in the Code; and
- The necessary tension should be maintained during the whole voyage.
1.4 The shifting of timber deck cargo is due mainly to the following causes which may occur singly or together:
- Lashings becoming slack due to compaction of the cargo during the voyage, unsuitable devices for tightening the lashing systems and/or inadequate strength of the lashings;
- Movement of the cargo across the hatch covers due to insufficient friction, particularly in ice and snow;
- Heavy rolling or pitching of the ship;
- Impact from heavy seas.
1.5 Great care should be taken to keep the ship in an upright condition during loading as even a slight list will impose a considerable load on the retaining uprights. The necessity for prudent ship handling during the voyage cannot be overstressed; imprudent ship handling can nullify even the best of stowages.
1.6 The lashings should be in accordance with Chapter 4 of the Code and may comprise the following types:
- Wire rope lashings which are used in addition to chain lashings. Each of these may pass over the stow from side to side and loop completely around the uppermost tier. Turnbuckles are fitted in each lashing to provide means for tightening the lashing at sea .
- Wiggle wires which are fitted in the manner of a shoelace to tighten the stow. These wires are passed over the stow and continuously through a series of snatch blocks, held in place by foot wires. Turnbuckles are fitted from the top of the foot wire into the wiggle wire in order to keep the lashingstight at sea .
- Chain lashings which are passed over the top of the stow and secured to substantial padeyes or other securing points at the outboard extremities of the cargo. Turnbuckles are fitted in each lashing to provide means for tightening the lashing.