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Cargo Work
Cargo Handling Safety
Safety while working with cargo gear
Derricks are long hollow steel booms rotating on
swivels (heel), they each have a part rope guy and a steel pendant which is
used for heaving and positioning the derrick and also to keep the derrick in
place. The rope is used in a tackle and can absorb sudden shocks, which come on
the derrick while in operation. On the opposite side to the cargo being worked
a preventer guy made of wire rope is fitted which is kept slightly slack than
the rope guy, This enables the rope guy to stretch before any load comes on the
preventer guy. This preventer is the last shock and strain absorber, if the
preventer is weak or is damaged it can part with disastrous consequences. So
maintaining the preventer and fixing it right is of utmost importance.
When the two derricks are used together such that one
derrick is positioned just above the loading area on the jetty and the other is
positioned above the un loading area within the hold, and the gynfall (load
lifting) wires are joined together, the arrangement is called a UNION PURCHASE.
This is the fastest method of working cargo, however the loads that this
arrangement can lift are less than the individual SWL of the derrick.
Additionally there is a risk of the angle subtended at the hook point between
the two-gynfall wires going beyond 120degrees when the gynfall wires together
act as a pulling force on the derricks laterally and can part the rope guys and
or the preventer wire.
Thus while the Union Purchase may be the fastest
method it requires careful rigging of the derricks as well as experienced winch
men to handle the operation together with the duty officer keeping an alert
watch on the working of the same.
Cargo blocks are maintained during the voyage, but due
to various reasons especially with bush bearings sheaves, the bearing may burn out. Prior breakdown however the block
would give an indication by a shrill metallic sound, the crew and duty officer
on deck is to be alert on deck and the moment a noise is heard the cargo work
is to be stopped and the cause investigated.
After each shift of cargo handling – when the
stevedores take a break all the cargo gear is to be examined for any wear and
tear, if required the defective items are to be replaced. If new blocks are
being put to use, they should be greased before fitting them. The test
certificates and the cargo-rigging plan should be checked to see that the
correct item is being fitted. Often a cargo block breaks down and on examining
it is seen that it had a SWL 5T marked on it. Instantly a 5T block is brought
from the store and fitted, it could be that the block that had been fitted
earlier was of a lesser SWL – so it is always better to check the rigging plan.
The handling of the cargo gear also needs to be
supervised and any extreme rough handling should be stopped. Where the gyn fall
wire rubs against the hatch coaming or gunwale suitable padding should be
place.
The derricks should be properly rigged and the
preventer wire should, if it has been rigged properly, stretch when the load is
in between the two derricks (in case of union purchase). With no load the
preventer should be with some slack.
The cargo hook should have a locking clip to prevent
the sling from slipping out of the hook.
Cargo handling areas should be cordoned off so that no
person is found walking or standing under a cargo load. Free passage may be
used of the non-working side of the cargo hatch.
A helmet is no safety for a load if it falls – helmets
are satisfactory if some loose small objects fall.
For heavy individual loads a swinging derrick is often
used either a single derrick is used where the guy ropes are removed and other
winch wires (also called steam guys) are used to control the movement of the
derrick.
A number of other types of rigging have over the years
been tried out some with great success and some with little.
Jumbo derricks were derricks attached to a Mast and
could lift as the name suggests heavy loads, the forward Jumbo derrick was
generally for extra heavy loads while the aft derrick was for slightly lesser
loads. In preparing for operation the Jumbo derricks required four winches – 1
for topping the derrick, one for lifting the load and two for swinging the
derrick. As such prior using the Jumbo derrick was rigged and the lashings were
then removed. The rigging entailed that four light derricks were inoperable
since their winches were requisitioned, so efficient planning on the part of
the chief officer was required.
Stulken derricks had a single boom but the rigging was
such that a single operator could control the movement of the derrick, another
advantage was that these derricks could service two adjacent holds by being
capable of being plumbed for either hold.
Velle derricks (with Thomson rig) were also very
popular for ships, which often loaded heavy loads such as containers; in this
the control again was unified into a single man operation.
The above derricks were however very difficult to rig
if the wire had to be changed, and often the crew would spend an entire day
rigging one derrick.
Cargo cranes are used on many ships and especially on
bulk cargo carriers. These may be light cranes for general cargo ships or
heavy-duty cranes for lifting huge grabs or containers.
Ships, which have slots for containers but also load
general cargo, are often fitted with cranes with SWL up to 40 tonnes. If a
single crane is incapable of being used to lift such heavy containers then two
cranes are ‘twinned’ to handle the load. The control is unified and both the
cranes work in tandem.
Hatch Covers
Hatch covers especially the Macgregor rolling hath
covers should be opened by a responsible person and after opening the hatch
covers should be locked to prevent their rolling and closing on their own due
to excessive trim.
Partially opening of hatch covers should be avoided
unless there is a means of locking them into place.
Prior opening a hatch cover the eccentric wheels
should be examined to see whether any have not been made upright for opening.
All loose gear on top of the hatch cover should be removed. Under no
circumstances should a hatch cover be opened with a load on it. Also the hatch
cover recess should be physically checked to see that not obstruction is
present and that no stevedore is napping in the recess.
Similarly a hatch cover should not be closed with load
on it and any deck cargo loaded onto hatch cover should be done only after the
hatch cover has be battened down (eccentric wheels turned down, cleats and
wedges locked.
Prior closing it should also be ensured that the track
way is clear of all ropes, portable light wires and any other obstruction and
that the locking has been removed.
Tween deck hatch covers once they are opened are to be
fenced off, generally stanchions (Height – 1.2m) are provided which have to be
rigged and the wire/ chains fitted. Nobody is to be allowed to work unless
these are rigged.
Cargo
Lighting
Portable lights are required to be rigged in holds
where there is no provision for fixed lighting system.
These lights are commonly called cargo cluster lights
and have 4 or more light bulbs fixed to a common pan shaped metal holder. A
wire mesh covers the front of the ‘pan’ and the inside of the ‘pan’ is painted
white to reflect the light.
The light is attached to a short length of small dia rope
to facilitate its being fixed at the coaming.
The lights are to be checked in the afternoon and
should be rigged and in place by sunset. The lights should be switched when
there is adequate light in the hold in the morning and should be un-rigged and stored
neatly.
They should be switched on only after the gangs come
for the work and should be promptly switched off once all have left the hold.
Often the cargo lights are not removed and the hatch covers are closed
especially when closing due to rain. This is fraught with danger, for the lead
is cut and the cluster light falls into the hold, the bulbs are hot and may
cause a fire, also the cut lead has power in it and may cause a short circuit
for the system or may electrocute any person close by.
An experienced crew should supervise the rigging of
cargo lights since if loading jute or other flammable cargo the distance off
from the cargo should be maintained. Also the shore people may tend to drag a
light inside the hold to facilitate loading, this should be supervised.
The electric cord should never lift the lights rather
the ropes attached for the same should be used.
In holds where fixed lighting is available the light
fittings should be inspected prior switching on and then only the lights are to
be switched on. Water seepage especially during rain may cause short circuits
and may eventually lead to fires.
All lights should be switched off when no longer
required.