Application Of Cargo : LOADING, DISCHARGING & STOWING CARGO
The aim of ship’s officers and crewmembers on board should be to prevent damage or deterioration whilst the cargo is under their care and to deliver it, as far as possible, in as good condition and order as it was when received aboard. If unacquainted with a certain type of cargo you should ascertain as to its nature and any necessary precautions. Therefore, the Master and officers of all vessels require a good working knowledge of the various kinds of cargo they are likely to carry: their peculiar characteristics, liability to damage, decay, or deterioration, their measurement, and the usual methods of packing, loading and discharging, stowage, dunnaging, etc., as the Master is responsible for the safe loading of his vessel and the proper stowage of the cargo.
The actual handling of the cargo in loading and discharging is done by stevedores, who are experienced men appointed for this purpose when a vessel arrives at a port. This does not release the Master from the responsibility for the safety of the ship and cargo, and he must supervise the work of the stevedores for general safety.
Therefore, during stowage the first consideration must be given to safety, i.e. the cargo must be stowed so that the ship will be stable and seaworthy, and it must be secured in such a manner that it cannot shift if the vessel encounters bad weather. The type of vessel, the cubic capacity of her compartments destined for the cargo and the appliances on board or on shore for loading or discharging, as well as the nature of the cargo, affect the question of how to stow the cargo in the best possible manner. The ship must be made neither stiff nor too tender. The next consideration is for the safety of the cargo itself: it must not be damaged by shifting; certain commodities become easily tainted by others, water might find its way into the hold and condensation or sweating must be prevented. Valuable cargo may be stolen or broached.
Finally, the Chief Officer must bear in mind the various destinations of the goods the ship carries, and arrange things, as far as he can, to see that the cargo for a certain place can be lifted out without disturbing the other cargo. The Chief Officer must watch closely the ship’s stability (i.e. what the ship’s trim is or how she is sitting).
Since a ship is supported by fluid pressure she will incline in any direction
according to the position of the weights placed on her. The trim, therefore, is the angle that a ship is making, fore and aft, with the water. The levels are read by numbers painted on the ship’s stem and stem. These are called draught marks. Another word is heel. This means a list or inclination from
one side to another, caused by loading. The Chief Officer must watch the load
lines. They are welded or punched on and then painted. Loading, discharging, stowage, lashing, securing, etc. are the operations and activities specific for each type of ship and cargo and these will be discussed in the following text (adapted from www.goradiaindustries.co.in ).
Before containerisation, apart from bulk, most cargoes were handled as general cargoes. Even vehicles were handled as general cargo before the advent of vehicle carriers and ro-ro vessels. Most ships had their own handling facilities in the form of derricks. Now the majority of cargo is shipped in containers. Thus there in no need for ships to have their own cargo handling gear and they rely entirely on shore facilities. Much of the general cargo carried now is of a type that cannot be readily packed into containers. General cargo is loaded from the dock by traditional dockside cranes except where the weight precludes this. To speed up loading, much of the cargo is unitised. The process of unitising consists of strapping together individual items of cargo to form a single unit. Ships designed to carry heavy cargoes usually have their own cargo handling gear in the form of heavy duty derricks or cranes.
Most cargo vessels used to have ‘tween decks (in between decks) in the holds but not many cargo ships are fitted with these now.
Cargo Stowage Plan (Plan krcanja)
CONVENTIONAL CARGO VESSELS. Conventional cargo vessels are constructed with several hatch openings on the weather deck into the holds below. In the deck arrangement of a conventional cargo ship, cargo is lowered through the main deck hatch opening into one of the between deck levels in the hold. It is landed in the hatch square and moved forward, aft, or into the wings by machine or by hand, where it is stowed. The hatches are numbered in order from bow to stern and the various deck levels are normally designated as upper tween deck, lower tween deck, and hold.
BREAK-BULK VESSEL STOWAGE PLANS. The break-bulk vessel cargo stowage plan is a complete diagram of a vessel’s cargo space showing the location (both on and below deck) of all cargo aboard ship. a. General. The stowage plan looks like a vessel when viewed from the side. It contains information about cargo stowed in the vessel’s hold, tween decks, and forecastle deck. The cargo shown in the tween decks is shown from the birdseye view. Only the lower hold is shown from the side or profile view. The cargo stowage plan is prepared by the loading terminal after the ship has been loaded and is used to facilitate the subsequent loading and discharge of cargo at all ports along the voyage. The cargo stowage plan contains—
- A summary of cargo to be discharged at each port.
- A summary and location of heavy lifts.
- Information on the capacity and location of heavy lifts.
- Information on the capacity and location of the ship’s boom.
- General information such as the location of special items of cargo
(protected, controlled, sensitive, mail, high-value, and so forth).