Journal of Ship Research, Vol 40, No 1 March 1996, pp 60-69.
This casualty attracted all kinds of academic attention
because it was a full scale experiment,
a VLCC hull failure in which the loading conditions were well known.
In this 1996 paper, Gordo, Guedes Soares, and Faulkner review
the attempts to analyse this problem and present their own.
In the as-built condition, the estimates of the hogging moment
required to cause progressive hull failure range from 18979 to 20630 million N-m,
with these author's estimate at 19164.
The moment which actually failed the ship was 17940 MM N-m.
If these numbers are right and the nearly 10 year old ship had not had any corrosion,
the Chief Officer probably would have gotten away with his mistake.
However, Gordo et al say
The last survey report found all cargo and ballast tanks in good condition
with the exception ballast tanks 3 where a greater degree of corrosion was found.
The location of these tanks is coincident with the location of the failure.
The last survey was in late 1979, early 1980 at Singapore.
or possibly in 1977 when the ship switched from DNV to BV,
We of course dont have the Class survey data,
nor do we know whether 3P and 3S were coated.
In 1977, the ship swithced from DNV to BV; we don't know why.
Anyway given the loading pattern, we only need a reduction
in strength from the as-built condition of about 10 pct
to generate a failure.
Class rules allow 25 pct reduction in wastage
before renewal is required,
and in practice wastage worse than this is often not caught.
It is not surprising that the hull failed.