Accidents and the lessons learned
Three of the world`s biggest tankers blow up within two weeks
On 12th December 1969 the Marpessa, a new giant
tanker of over 100,000 gross tons, was off Africa, returning to the
Arabian Gulf in the Middle East to pick up her second cargo of
crude oil. Suddenly, a massive explosion occurred in one of her
centre tanks, killing two of her crew and injuring others. Because
of damage to the lines on deck that carried water, it was
impossible to put out the fire. Marpessa began to
flood, and with her bulkheads giving way under the enormous
pressure of water, she sank on 15th December. When two other huge
tankers suffered similar explosions in the same area within the
next two weeks, Mactra and Kong Haakon
VII, it was apparent that this was no coincidence. All three tankers were cleaning their tanks at the time of the
explosions. It was decided that the equipment used to wash the
insides of the tanks with water had somehow ignited the dangerous
mixture of air and gas left when the crude oil had been pumped out.
Perhaps it was just a spark caused by metal grinding on metal, but
one theory held that the massive tanks of these vessels could
create their own weather conditions. It is possible that the
equivalent of a thunderstorm had occurred, with catastrophic
results. As a result, tank-cleaning equipment was modified. In
addition, an inert gas - carbon dioxide from the ship`s engines,
which will not support a fire - is pumped into the hold during tank
cleaning.
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