Packaged Timber
Being packaged this form of timber carriage is much more speedy and economical, and can be easily and quickly handled by fork lifts and mechanical means. Packaged timber is presently increasingly carried in unit loads of uniform size, and specialized vessels having suitable gear for unit loads are increasing in number. Several ports have separate terminals marked off for the working of such unit loads and the saving in terms of port stay and turnaround are great. Overall, the advantages of packaged timber are increased efficiency of handling, use of less manpower at both the loading ends, faster turnaround of the vessel, and lesser damage and breakage.
Timber Deck Cargo
Timber is not only carried in holds but also on deck. When timber is carried on deck there are great chances of its shifting, and with it not only the less of the cargo but damage to the vessel itself. It should therefore always be compactly, stowed and secured with adequate lashings. Some of the important procedures that must be observed when loading such cargoes are as follows: -
a) The packages should be securely bound and in solid form.
b) One tier of dunnage should be laid with the planks close up on each other and placed athwartships. This helps to spread the weight of the cargo over the deck.
c) After every tier of cargo all loose space should be properly filled in or checked, to minimize the chances of shifting.
d) The packages should be stowed such that the lashing arrangements are not blocked or obscured.
e) Packages of different weight and size are to be stowed separately or with suitable separation if stowed together, so as to prevent chances of damage.
f) As far as possible the packages should be stowed in a fore-and-aft direction so as to prevent shifting, also so as to enable proper lashings to be taken.
g) Necessary arrangements should be made to tighten the lashings during the voyage, as this might be necessary due to vibrations or movement of the vessel.
h) As far as possible only uniform sized packages should be loaded on deck and irregular packages stowed (in holds), so that
lashing and securing of the cargo on deck end be easier.
Whenever timber is stowed on deck it must comply with the regulations of the IMO code of safe practice for ships carrying timber deck cargoes. This code applied to all vessels of 24 metres (79 feet) or more in length and deals with following:
1) Stowage
The cargo should be compactly stowed and should not interfere with the navigation of the vessel, and with any arrangements that may be necessary for temporary steering of the vessel. The stow should also permit free access to accommodation and machinery spaces and should not endanger the safety of the crew in their normal duties. If the stow requires uprights these should be placed not more than 3 metres apart, and must extend to above the outboard top edge of the cargo. The uprights must be properly secured at their base and arranged such that each pair end be secured with athwartship lashings. Where practicable permanent ports of the ships structure can also be used as uprights.
2) Lashings
The entire deck stow should be provided with lashings which can be taken athwartships and secured to permanent eye pads or similar structures. Every lashing should be independent and should be provided by arrangements for shortening or lengthening adjustments turnbuckles as required during the course of the voyage. They should also be provided with sliphooks for releasing in the
event of an emergency. The lashings should be of 19mm chain or wire rope of equal strength and should be examined at least once in 12 months. If wire lashings are used they must be provided with a short length of chain so that their lengths can be regulated. The lashing spacing as shown in Figure 1.
3) Compactness
The stow should be as compact and tight as possible, with each tier properly chocked before loading the next tier. All spaces in the wells of vessels should be stowed as solidly as possible, this is more so in the case of vessels assigned timber loadlines, where the deckline is virtually raised to the level of the superstructure deck.
4) Logs, Pit Props And Wood Pulp
Logs should be stowed as compact as possible in a fore and aft direction and should be interlocked. They should be stowed to facilitate the rigging of lashings and uprights as in the cease of packaged timber. Pit props and wood pulp, although must meet the same stowage requirements, are usually loaded as per local practice.
5) Height Of Deck Stow
The height of cargo on deck would depend mainly upon the load bearing capacity of the deck. But in any case the height of the timber deck stow should not interfere with the navigation of the vessel. If the vessel is loading in a seasonal winter zone during winter or is expected to unload or pass through such a zone during the course of the voyage, the height of cargo on deck should not exceed the extreme breadth of the vessel.
6) Safety Of Crew
Safe access to crew accommodation should be provided by way of walk-ways with guard rails of 1 m height. Also an additional lifeline, along the centreline of the vessel, should be provided.
Stability
Careful attention is to be paid to the stability of the vessel when loading timber cargoes. It should be remembered that during the voyage timber deck cargo would absorb considerable moisture by way of rain, ice or snow. Due allowance must be given to this and the vessel should have adequate initial GM to allow for this factor. It would therefore be seen that the amount of timber carried on deck would have an important bearing on the ultimate safety of the ship. It is felt that as a general rule, on vessels fully loaded with timber, not more than of the weight of timber carried should be stowed on the open deck.
Among the stability information carried on ships the Master and Officers are also to have suitable information to enable them to foresee the stability characteristics of the vessel in relation to the deck loads, under all conditions of the intended voyage. In planning the loading and voyage with timber deck cargo the guidance information contained in the vessels stability booklet must be observed.
MODULE 5 - BULK CARGOES
Hazards
In general, the hazards may be considered to fall into three categories: -
1) Improper weight distribution resulting in structural damage
a) Excessive concentration of weight on deck or inner bottom.
b) Improper distribution of weights between holds.
2) Improper stability or reduction in stability a) Too stiff a vessel resulting in violent rolling and possible cargo shifts and structural damage.
b) reduction in stability as a result of:-
i) A transverse shift of the cargo surface as in the case of “DRY” cargoes and cargoes which do not become fluid when wet.
ii) A transverse shift of “WET” cargoes which become fluid and give rise to free surface effects.
3) Chemical Reaction: A few cargoes like fine copper ore, Metal turnings and borings are subject to spontaneous heating.
“DRY” bulk cargoes include “ores and similar