Annex A

Previous Page | Next Page

Advice on Stowage Practices

1. General

1.1 The stowage practices described in this annex have been found to achieve satisfactory results, provided that account is taken of the recommendations of chapters 1 to 6. Although specific conditions may dictate a departure from these guidelines, the basic principle as detailed in 1.2 should nevertheless be adhered to.

1.2 The basic principle for the safe carriage of timber deck cargo is, as indicated earlier, a stow as solid and compact as practicable. The purpose of this is to:

1. prevent slack in the stow which could cause the lashings to slacken;
2. produce a binding effect within the stow; and
3. 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:

1. the strength of all lashing elements should be at least equal to that recommended in the Code; and
2. 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:

1. lashings becoming slack due to compaction of the cargo during the voyage, unsuitable devices for tightening the lashings systems and/or inadequate strength of the lashings;
2. movement of the cargo across the hatch covers due to insufficient friction, particularly in ice and snow;
3. inadequate strength of the uprights due to poor material properties and/or excessive forces;
4. heavy rolling or pitching of the ship;
5. impact from heavy seas.

1.5 Great care should be taken to keep the ship in an upright condition during the 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:

1. Hog lashings are normally used over the second and third tiers and may be set "hand tight" between stanchions. The weight of the upper tiers when loaded on top of these wires will further tighten them (see figure 1).
2. 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 (see figure 2).
3. Wiggle wires which are fitted in 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 footwire into the wiggle wire in order to keep the lashings tight at sea (see figures 3 & 4).
4. 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 at sea (see figure 5).

1.7 Systems for securing timber deck cargoes are shown in figures 3,4,5,6 and 7.

2. Packaged Timber and Cants

2.1 Timber packages are usually bundled by bandings fastened mechanically (hard bundled) or by hand (soft bundled). The packages may not have standard dimensions and they are not always flush at both ends. The stowage problem is compounded by differences in the lengths of packaged timber when the packages are stowed on board the ship. Moreover, the master of the ship often has no influence on the order in which the packages are delivered.

2.2 Packages which contain random lengths likely to disrupt the compaction of the stow should not be loaded on deck. Other packages of random lengths capable of compact stowage may be loaded on deck in a fore and aft direction but not on exposed surfaces or in the stowage outboard of the hatch coamings (see figures 8 and 9).

2.3 Packages for deck stowage should be solidly made up. They should have bands adequate to prevent slackening or disintegration of the package during the voyage, which could cause a loosening of the stow as a whole. Slack bands on the top surface of the deck cargo are dangerous foot traps.

2.4 Cants are usually bundled by banding, but the irregularities caused by varying thicknesses and curved sides make compact bundling very difficult to achieve. Because of these factors, considerable broken stowage is encountered as well. The tendency is for the package to assume a rounded cross section within the bands due to the curved sides of the individual pieces (see figure 10).

2.5 A solid stow of packaged timber is not always possible as the packages of timber have different measurements, may be partially soft bundles, and gaps may exist between the packages. It is essential, however, that the upper tier and outboard packages be stowed as compactly as possible and the upper tiers chocked as necessary.

2.6 The methods used to stow cargoes of loose timber for transport cannot always be applied to the transport of packaged timber as:

1. packaged timber cannot be stowed to give a compactness as tight as that achieved with loose timber. Lashings may therefore be less effective;
2. packaged timber cannot be stowed between the uprights as densely and with so few gaps as loose timber. The uprights may consequently have to sustain greater loads when packaged timber is being carried and may absorb the forces generated by the cargo when it is moving.

2.7 Before commencing to load on the deck or hatches a firm and level stowage surface should be prepared. Dunnage, where used, should be of rough lumber and should be placed in the direction which will spread the load across the ship’s underdeck structure and assist in draining.

2.8 Due to the system of athwartship lashing, the stowage of packages should generally be in the fore and aft direction; the wings of the upper two tiers should always be in the fore and aft direction. It is advisable to have one or more non-adjacent tiers stowed athwartships when above the level of the hatches in order to produce a binding effect within the cargo. Also, athwartship packages should be carried above the hatches to interlock the load. If packages with great differences in length are to be loaded, the longest package should be stowed fore and aft outboard. Short packages should be confined to the inner portions of the stowage. Only packages flush at both ends can be stowed athwartships (see figures 11, 12 and 13).

2.9 The timber should be loaded to produce a compact stow with a surface as level as practicable. Throughout the loading, a level and firm stowage surface should be prepared on each working tier. Rough dunnage, if used, should be spread over at least three adjacent packages to produce a binding effect within the stow, particularly in the wings.

2.10 Any gaps occurring around packages in which the cargo may work at sea, such as in the vicinity of hatch coamings and deck obstructions, should be filled with loose timber, efficiently chocked off or effectively bridged over. For this purpose a supply of timber chocking material should be made available to the ship.

2.11 Packages at the outboard edges of the stow should be positioned so that they do not extend over the padeyes and obstruct the vertical load of the athwartship lashings. The end of each deck stow should be flush in order to minimize overhangs to resist the influence of green seas and to avoid the ingress of water.

2.12 Large heavy boards and squares of timber, when loaded on deck in combination with packages, should preferably be stowed separately. When placed in upper tiers, heavy pieces of timber tend to work loose at sea and cause some breaking of packages. In the event that boards and squares are stowed on top of packages they should be efficiently restrained from movement.

2.13 When the final tier is loaded on a large number of tiers, it may be stepped in from the outer edge of the stow about 0.5-0.8 m (a half package).

3. Logs

3.1 If logs are loaded on deck together with packaged timber, the two types of timber should not be intermixed.

3.2 Logs should generally be stowed in a fore and aft direction to give a slightly crowned top surface such that each log is adequately restrained from movement when the system of securing is in place and set up taut.

3.3 In order to achieve a compact stow, the butt of each log or sling of logs should not be in the same athwartship plan as those adjacent to it.

3.4 In order to achieve a more secure stowage of logs when stowed on deck, a continuous wire (hog wire) should utilized at each hatch meeting the specification of chapter 4 of this Code. Such hog wire should be installed in the following manner:

1. at approximately three-quarters of the height of the uprights, the hog wire should be rove through a padeye attached to the uprights at this level so as to run transversely, connecting the respective port and starboard uprights. The hog lashing wire should not be too tight when laid so that it becomes taut when overstowed with other logs;
2. a second hog wire may be applied in a similar manner if the height of the hatch cover is less than 2 m high. Such second hog wire should be installed at approximately 1 m above the hatch covers;
3. the aim of having the hog wires applied in this manner is to assist in obtaining as even a tension as possible throughout, thus producing an inboard pull on the respective uprights.
   
   

4. Pulp Wood and Pit-Props

4.1 When these items are stowed in the manner described below, good compaction of the deck cargo can be obtained.

1. In the deck area clear of the line of hatches, the cargo should be stowed in the athwartship direction, canted inboard by some cargo laid fore and aft in the scuppers.
2. At the centre of the stow, along the line of hatches, the cargo should be laid in the fore and aft direction when the wing cargo has reached hatch height.
3. At the completion of loading, the cargo should have a level surface with a slight crown towards the centre.

4.2 To prevent the cargo from being washed out from below its lashings, it is recommended that nets or tarpaulins be used as follows:

1. the ends of each continuous section of deck cargo, if not stowed flush with the superstructure bulkhead, may be fitted with a net or tarpaulin stretched and secured over the athwartship vertical surface;
2. over the forward end of each continuous section of deck cargo and in the waist of the ship the top surface may be fitted with a net or tarpaulin stretched and secured across the breadth of the cargo and brought down the outboard vertical sides to securing points at deck level.

Previous Page | Next Page