Organization of cargo handling operations
As you know merchant sea ports are intended to perform economic and administrative functions. Main administrative functions are ensuring of safe navigation and proper order within the port. Economic functions are loading and discharging operations, servicing of inbound and outbound vessels, forwarding and warehousing operations.
Cargo handling is in my opinion the most important function of the port. To transport cargo from water modes of transport to shore modes is the basic reason why such an institute as cargo port was established. During ages all activities concerning sea trade developed greatly. Cargo handling is not exclusion. Originally the cargo operations were effected on a very low level. Cargo was loaded and discharged by ordinary workmen – stevedores by means of the most simple equipment: slings, nets, winches, derricks. Nowadays this is very complicated and high organized process. The whole process consists of several stages. Prior to loading stage plan and cargo plan is drawn up. Stevedores headed by foreman effect stowage of the cargo and sufficient securing and lashing of the cargo. Three very important documents should be taken into consideration during this stage. Mates receipts are issued for each consignment showing the quality and the quantity of the cargo taken onboard, B’s/l are issued and signed by the master on the basis of these documents. And the last one is charter party, that regulates the rate/speed of cargo handling operations. Prior to discharging stevedores require stowage and cargo plan as far the discharging shall be effected very carefully in roper order, consignments for different consignees shall not be mixed.
Cargo handling operations are effected by stevedores by means of various cargo facilities. They are port cranes, floating cranes, gantry cranes, bridge cranes for general cargo, cranes equipped with grabs, elevators, conveyors and suction plants for bulk cargo, pipelines for liquid cargo. Sometimes they can even be effected automatically.
The labor in the stevedoring company or department in the port who is responsible for cargo handling operations may be divided into: stevedores – ordinary workmen, foremen – who are responsible for the work and safety of groups of stevedores called gangs, chief foreman is responsible for all work onboard the ship, superintendent is responsible for handling of all ships in the dock.
As far as nowadays many vessels call in the ports every day and each of them require to loaded and discharge, and such operations may be done only by means of cargo handling facilities and adequate personnel all cargo handling operations are arranged in strict schedule by planning department of the port. Commercial department is in charge of finances and profit of cargo handling complexes.
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LOADING
Before the commencement of loading the ship all necessary preparations should be made both in the port and on board the ship to be loaded. First of all, the cargo plan must be drawn up. In Russian ports this document is usually drawn up at the Chief Controller's Office since this office directs cargo work in the port, while in foreign ports the Ship Agent and the Master draw up the cargo plan.
Before loading the Chief Stevedore (or Boss Stevedore as he is called sometimes), who is in charge of loading the ship, secures the necessary number of stevedore gangs, obtains port cargo handling facilities, if necessary, and supplies the tackles which the stevedores need. He also supervises the correct tonnage allotment for the holds. In the process of loading the Chief Stevedore checks up if cargoes are properly stowed and trimmed, for proper stowage of cargo ensures the stability of the ship loaded. It is also his duty to see that the cargo should be properly
secured from shifting.
On board the ship the Cargo Officer sees to that all necessary preparations for loading should be made. Under his supervision the crewmen clear the hatches. They roll back the tarpaulins from the hatches, remove hatchcovers, remove beams The crewmen also get ready the ship's winches, derricks and cranes, if any.
Different kinds of cargo require different equipment and appliances. So, for loading cases steel slings, nets and pallets are necessary; bags require nets and canvas slings; heavy lifts are loaded either with heavy duty derricks (or «jumbo» derricks as they are also called), the lifting capacity of which is over 5 tons, or with ship's or quay cranes; for loading flowing cargoes elevators and grabs are used; for loading containers there are gantry cranes and container bridges having container claws; for loading RO-RO vessels or various sorts of vehicles (such as autotrucks, forklift trucks, trailers and others) are used; as to tankers, they are loaded with the help of pipelines and hoses.
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STOWAGE
Stowage is the placing of cargoes either in ship's hold or on her deck. The method of stowage must ensure the following:
1. The preservation of crew and ship from danger of injury arising from the manner in which the cargo is stowed.
2. To protect the cargo from damage, loss or deterioration, and to ensure its «sound delivery».
3. The economy of cargo space that depends on the vessel's earning capacity.
4. The highest possible rate of port speed, i.e. the rate at which the vessel is capable to load or discharge (unload) her cargo.
A plan showing the disposition of cargoes throughout the ship should be drawn up in all cases. It is called the stowage or cargo plan.
The cargo plan should be drawn up carefully. It will make the distribution of cargo pieces in the holds easier and it will help to avoid cargo claims. When loading for more than one port, a different colour should be used to indicate the cargo for each separate port.
While stowing the cargo the stevedore and the cargo officer should ensure the ship's stability and seaworthiness. Cargo must be stowed and fastened reliably to avoid shifting if the ship rolls and pitches during a storm. A reliable fastening the cargo prevents possible damage from chafing, breaking and crushing.
Special attention should be paid to the stowage of barrels. For this kind of cargo bottom stowage is preferable in order that leakage may find access to the bilges without risk of damage to other cargo.
The method of stowage depends on the kind of the cargo. Light cargoes are stowed on top of heavy ones, the latter being given bottom stowage.
The stevedores and ship's cargo officers use such a term as «broken stowage», which is used to express space which is lost and unoccupied by cargo between and round the packages; space occupied by dunnage; space at sides, ends and on top of cargo, also in way of pillers, bulkheads, stiffeners, etc.
This loss of space varies according to the nature of the cargo carried with free flowing cargoes like grain, sand, etc., provided they are properly trimmed, the loss is small.
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With bag cargo and handy cases of uniform dimensions, such as tea packages, canned goods, very full stowage is possible.
On the other hand, irregularly shaped packages, varying in size and form, large packages, such as machinery, boilers, large reels and motor cars, cylindrical containers, etc., the loss of space is very high, and it sometimes reaches 25 per cent.
The loss of cargo space can be avoided by:
1. Compactness of stowage.
2. Selecting packages which by their sizes and form are suitable for filling broken stowage.
3. Always keeping a supply of such packages specially shipped for this purpose, close and ready at hand in the holds, for the use when wanted.
4. Special selecting the cargo suitable for filling beam spaces.
DUNNAGE
Dunnage is the material used for protecting cargoes from possible damage.
Correct dunnaging of cargoes is extremely important.
Dunnaging serves the following purposes, according to the nature of the cargo carried:
1. to protect it from contact with water from the bilges, leakage from other cargo, from the ship's side or from double bottom tanks;
2. to protect it from contact with moisture or sweat which condenses on ship's sides, frames, bulkheads, and falls down on the cement caps, from which it finds its way into bilges;
3. to prevent chafage of packages.
For ordinary cargoes the permanent ceiling is sufficient provided it is dry, clean and free from oil stains.
Where the condition of permanent ceiling is bad, additional dunnaging and matting are necessary.
Dunnage must be dry, clean, sound and free from stains which may contaminate the cargo in contact with it.
The use of dunnage retaining the odour of a previous cargo should be avoided. The types of dunnage materials best suited to any particular cargo are as follows: boards, battens, cardboard, cardwood, tarpaulins, mats, plywood.
The selection of dunnage for some cargoes depends on a kind of a cargo.
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With a bagged cargo size is the criterion for selection. Wide boards are preferable to smaller sizes, for, by placing the former closely together a flooring is formed which does not prevent air circulation and it prevents the sagging of the bags between the boards.
The considerable top weight of a bagged cargo will cause bottom bags to tear by sagging through narrow, widely spaced and badly laid dunnage.
A general cargo may be dunnaged efficiently almost with any types of wooden boards or battens provided they fulfil the requirements of cleanliness. The boards or battens, however, should be selected in accordance with the sizes of the packages or bales necessary for a compact stow.
Appropriate wooden dunnage may be laid prior to the commencement of loading a bagged cargo, for, with most bagged cargoes a complete tier is first laid over the floor of the hold.
General cargo, however, due to different shapes and sizes, will break up and misplace any previously laid dunnage. It is better therefore to have a liberal supply of dunnage available in the compartment and use it as required when stowing the packages.
Double dunnage should also be laid. The first tier is arranged athwartships in order to provide water courses toward the bilges, and the upper tier fore and aft.
DISCHARGING
Discharging (unloading) is accomplished under the supervision of a stevedore and it is performed by dockers usually headed by a foreman. When the ship is to be unloaded the Second Mate (Cargo Officer) gives a Cargo plan and Bill of Lading to the stevedore. According to these documents the latter begins unloading the ship.
The crewmen get ready winches and cranes, derricks, shackles, blocks, slings, sling hooks, chain slings, timber dogs, falls of tackle, guys.
All these appliances should be preliminary inspected for possible signs of wear. When the stevedore made sure that cargo gear was all right, he should arrange some wire nets, trays, pallets, wire slings, rope slings and canvas slings for unloading cargoes from the holds. The unloading operation is the process of lifting the cargo pieces from the holds and lowering them down on the quay. The number of cargo units placed either on a pallet, tray or any sling is called a draft.
Fork-lift trucks and lorries deliver cargoes to the warehouses. Sometimes the cargoes may be unloaded directly from the ship's holds into lighters. If there are some extra weights in the holds they may be unloaded by heavy lift cranes, heavy derricks, gantries or even by floating cranes. The cranes mentioned above (except floating ones) are of lifting capacity up to 10 tons. The floating cranes can handle heavy cargo pieces up to 300 tons. The condition of cargo pieces should be noted on the spot4. Damaged packages, torn sacks and leaky barrels are put aside immediately.
WAREHOUSES AND SHEDS
Cargoes which must be carried by ships are usually delivered to a port prior to ship's arrival. So on ship's mooring they waste no time and loading operations may begin immediately. Cargoes are of different types and value and most of them are to be stored in special warehouses and sheds. This storing protects cargoes from any damage caused by sun rays, snow, rain and by some other factors. Only a few kinds of machinery and equipment packed in boxes can be placed on quays without roof protection. Warehouses and sheds are used for storing cargoes during any periods of time before they are conveyed to the quays and loaded on board ship. There are single-floor-, two-floor-, and multifloor sheds and warehouses in a modern port. In the warehouses special care should be taken to ensure even distribution of natural and artificial lighting. Walls, roofs and columns should be painted in light colours. Floors must be strong and they must withstand considerable weight to the packages stowed. The construction of warehouses and sheds must be such as to avoid the difficulty in arranging the flow of cargoes from the various floors without interruption.
Clearances between the packages stowed in the space of the warehouse must be quite sufficient for free shifting and trimming the cargo. Perishable goods such as fish, meat, fruits, vegetables, paultry, butter and some other goods are kept in port cold-stores. Port's warehouses and sheds are linked with quays by railways and asphalt roads. This makes transportation of goods from the warehouses to the ships easy and convenient.
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