|
Bulkers With
Double Skin
While double hull tankers
have proved their merit beyond doubt, studies are in hand to improve the level of safety
in the design and construction of bulkers. Accordingly SOLAS Chapter XII – Additional
Safety Measure for Bulk Carriers has been brought into force from 1 July 1999. This
has stipulated two main recommendations which are to be followed within a time bound
program according to the age of the ship, as follows: -
-
All new building single side skin bulkers of
length 150m and more, carrying cargo of density 100 kg/m3 and above, such as
grains, and timber, should have the strength to withstand flooding of any one cargo hold.
-
For existing ships carrying cargo of density
1780 kg/m3 and above, such as iron ore, pig iron, bauxite, cement etc. the
transverse watertight bulkhead between the two foremost cargo holds and double bottoms of
the foremost cargo holds, should be able to withstand pressure of water ingress and the
related dynamic effect.
A single skinned bulker is
subject to all three forms of attack viz., corrosion, fatigue and mechanical damage. The
most vulnerable area is the watertight bulkhead between forward hold and the second hold,
including the double bottom of the ship at this location. The critical age for the bulkers
is considered between 14 to 18 years, where most of the damage has been observed
statistically. These bulkers now constituting a large tonnage of the world fleet will
require substantial investment in hull work, if they are to be kept going in service. A
question will always be asked, whether the recommendation made in SOLAS Chapter XII and
Enhanced Survey Program made mandatory, is enough to make bulkers a safe house.
Studies are in hand and
various theories are being propounded and we may see emergence of Double Skin
Bulkers in not so distant a future.
|
