June 2016
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World Coal
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49
Harold A. Walker and Donna F. Walker, PICOR, USA,
explore the dangers
of hatches and hatch covers on ocean-going coal vessels and how a new
technology could avoid such risks, reduce costs and improve safety.
C
oal and other fossil fuels are under international
political pressure due to the acceptance by many
politicians and environmental groups of the
negative effect carbon dioxide emissions have
on the environment. This pressure will result in a difficult coal
market for the short term but increasing demand for energy
will require the total energy supply to increase in the long
term. Those with an investment horizon in excess of ten years
would do well to plan and build before then.
Ocean-going bulk carriers transport around 1 billion tpy of
coal. These vessels are built in many sizes – generally
determined by where they will be operating. Handysize vessels
are generally designed to carry 40 000 t – 45 000 t, panamax
vessels are designed to traverse the Panama and Suez Cannels
and carry 60 000 t – 80 000 t, and vessels designed to travel
round the Cape of Good Hope and Cape Horn generally carry
over 80 000 t. Ocean transportation of coal is extremely
economical but there is room for improvement.
Loading and unloading vessels
Coal loaded onto ocean-going bulk carriers is generally
loaded by clamshell buckets or other types of equipment
through hatches above holds, which contain the coal during
shipment. At the destination port, most ocean-going bulk
carriers are unloaded by clamshell buckets or some other
device through the same hatches. During unloading, it is
necessary to lower mobile equipment into the holds to
physically move some of the coal into an area that can be
reached by the unloading equipment. While this process is
accepted as normal, it does have some consequences that
