The form of
cargo-handling equipment employed is basically determined by the nature of the
actual cargo and the type of packing used. The subject of handling facilities
raises the important question of mechanization.
BULK CARGO
HANDLING EQUIPMENT
So far as dry
bulk cargoes are concerned,
handling facilities may be in the form of power-propelled conveyor belts,
usually fed at the landward end by a hopper (a very large container on legs) or
grabs, which may be magnetic for handling ores, fixed to a high capacity travel1ing
crane or travel1ing gantries. These gantries move not only parallel to the
quay, but also run back for considerable distances, and so cover a large
stacking area, and are able toplumb the ship's hold. These two types of
equipment are suitable for handling coal and ores. In the case of bulk sugar or
when the grab is also used, the sugar would be discharged into a hopper,
feeding by gravity a railway wagon or road vehicle below. Elevators (US) or
silos are normally associated with grain. They may be operated by pneumatic
suction which sucks the grain out of the ship's hold.
LIQUID CARGO
HANDLING EQUIPMENT
The movement of
liquid bulk cargo, crude oil and derivatives, from the tanker is undertaken by means
of pipelines connected to the shore-based storage tanks. Pumping equipment is
provided in the tanker storageplant or refinery ashore, but not on the
quayside. In view of the dangerous nature of such cargo, it is common practice
to build the special berths a small distance from the main dock system on the seaward
side. Oil cargo is discharged from the ship’s tanks, via the cargo piping
system to the main ship’s manifold usually situated amidships, on either port or
starboard side. From there by means of shore-based loading arms oil is
transferred to the shore manifold and is then distributed to shore-based storage
tanks on the oil terminal. The loading arm hose must be flanged oil-tight to
the ship’s manifold so that oil spills can be avoided.
GENERAL CARGO
HANDLING EQUIPMENT
With regard to general
cargo (goods, merchandise, commodities), also referred to as break bulk cargo, almost
90% of all such cargo in most liner cargo trades today is containerized.
Meanwhile the system of dockers handling cargo will continue, but doubtless every
effort will be made to expand the a1ready extensive use of various types of
mechanized cargo-hand1ing equipment. General cargo is handled by cranes on the
quay, floating cranes or by the ship's own cargo gear (deck cranes, derricks, etc.).
Attached to such lifting gear is a shackle which links the crane or derrick with
the form of cargo-handling equipment being used. For most lifts a hook is used.
There are numerous types of tools or loose gear that can be attached to the shipboard
or shore-based lifting gear. They include the sling or strop, which is probably
the most common form of loose gear. Such equipment, generally made of rope, is ideal
for hoisting strong packages, such as wooden cases or bagged cargo, which is
not likely to sag or be damaged when raised. Similarly, snotters or canvas
slings are suitable for bagged cargo. Chain slings, however, are used for heavy
slender cargoes, such as timber or steel rails. Can or barrel hooks are suitable
for hoisting barrels or drums. Cargo nets are suitable for mail bags and
similar cargoes that are not liable to be crushed when hoisted. Heavy lifting
beams are suitable for heavy and long articles such as locomotives, boilers or
railway passenger coaches. Cargo trays and pallets, the latter being wooden or
of steel construction, are ideal for cargo of moderate dimensions, which can be
conveniently stacked, such as cartons, bags, or small wooden crates or cases.
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