Various commodities carried by general cargo ships - stowage methods and precautions

Various commodities carried by general cargo ships - stowage methods and precautions

Stowage methods and precautions

Cargoes should be stowed and secured in a manner that will avoid exposing the ship and persons on board to unnecessary risk. The safe stowage and securing of cargo depends upon proper planning, execution and supervision by properly qualified and experienced personnel.

The planned procedures for the handling of cargo should be agreed with berth or terminal operators in advance of loading or unloading. In the case of dry bulk cargo (excluding grain), procedures should follow the IMO Code of Practice for the Safe Loading and Unloading of Bulk Carriers, with the associated IMO Ship/Shore Safety Check List. For grain there is more detailed guidance in the International Code for the Safe Carriage of Grain in Bulk.

Loading, stowage and securing of cargo other than bulk cargo is to be carried out in accordance with the ship's approved Cargo Securing Manual.

Handling various commodities on board general cargo ships need extra caution . Below is our guideline prior shipment of different cargoes ( reference only ). One must also be guided by practice of good seamanship.

Bagged Cargo (paper bags)

These should be stowed on double dunnage. Ideally the first layer should be stowed athwartships on vessels equipped with side bilge systems. Steelwork should be covered by brown paper or matting to prevent bags making contact.Torn bags should be refused on loading. Canvas rope slings should be made up in the hatchway centre to avoid dragging and bursting bags. Hooks should never be used with paper bag cargoes.When stowing, bag on bag stow is good for ventilation, whereas bag on half bag is poor for ventilation but good for economical use of space.

Barrels

Stowed ‘bung’ uppermost on wood beds, in a fore and aft direction. ‘Quoins’ are used to prevent movement of the cargo when the vessel is in a seaway. Barrels should never be stowed more than eight high.

Fig: Bulk coal loader incorporating centralised dust control system

Coal (bulk)

Check that bilge suctions are in working order and that limber boards are tight fitting. Remove all spar ceiling, stow in the ’tween deck, and cover with a tarpaulin or other similar protection. Plug ’tween deck scuppers. Remove all dunnage and make arrangements for obtaining temperatures at all levels if engaged on a long voyage. Ensure that the coal levels are well trimmed and provide the compartment with surface ventilation whenever weather conditions permit.

Copra

As it is liable to spontaneous combustion, it should be kept dry and clear of steelwork surfaces, which are liable to sweat. Copra beetle will get into any other cargoes which are stowed in the same compartment.

Cotton

Bales are liable to spontaneous combustion, so that the hold must be dry and clean, free of oil stains etc. Adequate dunnage should be laid and all steelwork covered to prevent contact with cargo.Wet and damaged bales should be rejected at the loading port.

Hoses and fire appliances should be on hand and readily available during the periods of loading, fire wires being rigged fore and aft.

Edible Oils

Deep tank stow, for which the tank must be thoroughly cleaned, inspected, and a certificate issued by a surveyor.

Heating coils will be required, and these should be tested during the period of preparation of the space. All inlets and outlets from the tank should be blanked off. Shippers’ instructions with regard to carriage temperatures should be strictly adhered to. A cargo log of these temperatures should be kept. Extreme care should be taken on loading to leave enough ‘ullage’ for expansion of the oil during passage. Overheating should never be allowed to occur, as damage to the oil will result.

Flour

Susceptible to damage from moisture or by tainting from other cargoes, it should never be stowed with fruit, new timber or grain. Should a fire occur during passage,‘dust explosions’ are liable from this cargo.

Fruit

Usually carried in refrigerated spaces, especially over long sea passages, it may also be carried chilled under forced ventilation.However, regular checks should be made on ventilation system and compartment temperatures. This cargo gives off CO2 and will consequently require careful ventilation throughout the voyage.

Glass (Crates)

Crates of glass should never be stowed flat, but on their edge, on level deck space. Plate glass should be stowed athwartships and window glass in the fore and aft line, each crate being well secured by chocks to prevent movement when the vessel is at sea. Overstowing by other cargoes should be avoided.

Vehicles

These should be stowed in the fore and aft line, on level deck space.They should be well secured against pitching and rolling of the vessel by rope lashings. Fuel tanks should be nearly empty. Close inspection should be made at the point of loading, any damage being noted on acceptance.

Methods of cargo carriage for different commodities onboard

In general, commodities are either moved in bulk or as general cargo. Bulk and general cargoes are defined relative to their means of transport and the cargo mix onboard. If, for example, a ship carries a homogeneous cargo lot which is not packed in any form, this is a bulk cargo: oil carried directly in tanks, grain carried directly in holds or pig iron loaded directly, in holds.

When cargoes are packed and mixed onboard, it is referred to as general cargo. Most finished goods are shipped as general cargo, while raw materials in bigger lots are usually bulk cargoes.

The distinction between bulk cargoes and general cargoes is not strict. There are examples of more than one bulk cargo being carried onboard the same ship, in different holds or sections. Similarly, there are general cargoes which fill up the whole carrier, e.g. shiploads of sugar in bags. This is referred to as unit loads of general cargoes (which does not necessarily involve pallets or containers). The opposite, where the ship carries different cargoes packed differently is referred to as general break bulk cargoes. Such cargoes may consist of pallets, unpacked machinery, drums, crates and so on.

The table below clarifies the difference between the physical form of a cargo and the way it is shipped.

Cargo shipment

Commodities, dry as well as liquid, may be shipped in unit loads, in break bulk or as bulk cargo. It should be noted that terminology with regard to the above is not fully consequent, and that additional terms are in use. The term "parcel bulk" in chemical carriers is one example of this; up to 30 different chemicals may be transported simultaneously onboard the same ship.

There exists a third; “hybrid” form of moving cargoes, involving slurry techniques. Dry bulk cargoes may be transformed into slurries and moved in a form similar to that of liquid bulk. This has been applied to coal and iron ores, where the ores or the coal are mixed with water and transported by means of pipelines.

On a world wide basis, almost all the liquid commodities, measured in tons, are moved in bulk. Important dry goods, like grain, coal, ores, tapioca, copra and salt are similarly moved in homogeneous unpackaged lots. Such bulk cargoes can be handled in many different ways. Liquids are moved in pipelines, grain are mostly loaded by conveyors or chutes and unloaded pneumatically, while ores and coal are mostly moved with conveyors or grabs.

The cargo characteristics will influence the choice of ship needed for a specific job. Different ships are constructed to carry different bulk cargoes.

Similarly, the cargo access equipment have been constructed to cater for different commodities. The equipment available for cargo handling at the intended ports of loading and discharge will also be reflected in the type of ship needed for a specific job. If, for example, no cranes are available in the discharging port, a ship equipped with cranes will have to be chosen for the transport task.

Summarized below some more details on general cargo ship cargo handling procedure and operational info:

Cargo handling procedure for general cargo ship

Various commodities carried by general cargo ships - stowage methods and precautions

Methods of cargo carriage for different commodities onboard

Machinery system main info pages