As usual the Australian report is a good one
and should be required reading for anyone interested in marine safety.
This casualty is a poster child for what's wrong
with tanker and bulk carrier regulation.
The Malaysian ship had loaded iron ore at Port Hedlund
for discharge at Port Kembla,
under a single voyage cabotage exemption.
The Giga 2 had 2 diesel generators and one T/A.
Due apparently to a crew screw up,
one of the D/A's was out of operation.
The other D/A had insufficient capacity to support
the discharge, so they had to hire a portable generator.
But the lack of power was to come into play.
Under Class rules, you are supposed to be able
to operate the ship with one generator off line;
but, post-1980, the electrical loads used to determine
how much capacity that requires are hopelessly optimistic.
So in reality, this requirement is rarely met.
When I was operating tankers,
we found that to meet the redundancy requirement,
the generators had to be at least 25 pct larger
than the minimum allowed by Class.
As a bulk carrier is discharged,
she must take in ballast to keep the height of the hatch coamings
below the limit imposed by the unloader.
The combination of insufficient electrical power,
some valves that were in bad shape,
prevented the Giga 2 ballasting to keep up with the discharge,
and the terminal threatened to throw her off the berth.
There was still xxxx tons in No 5 hold.
The decision was made to ballast the empty No 4 hold.
The ship's manual in Japanese said this was allowable
provided the depth of water in No 4 was no more than 14 m.
This was done by running hoses thru the manholes,
but the job went slowly since all the manhole nuts and studs
were badly corroded.
As the No 5 holds was discharged it became clear that
the ladder into No 5 was badly corroded and needed repair.
Two terminal workers were sent down to inspect
and clear out the space directly below the ladder.
The ladder was in such bad shape that they
were given a safety rope, which ended up saving a life.
Just as the two men started coming back up,
the bulkhead between 4 and 5 failed
and water flooded into No 5.
One man was able to hang on to the ladder and get back to deck.
The other was not, but fortunately he had tied
the safety rope around his chest.
The Shift Supervisor rushed to the ship,
went down, managed to grab on ot the rope,
and with help get the unconscious man back on deck.
(Where was the ship's crew?)
They were able to get him breathing again.
The Australian found the bulkhead to be severely wasted.
The deep webs had detached from the upper stool.
The corrugated bulkhead itself had an original thickness of 17.5 mm.
39 pct of the 116 thickness emeasurements they took,
were below the max permissable wastage of 13.125 mm (25 pct).
The ship's class is NKK.
At her 3rd Special Survey, Class took 12 thickness readings
on the 4/5 bulkhead (frame 193) of which 9 were between
13.9 mm and 14.22 mm, just within ``permissable'' levels.
The bulkhead was designated a ``suspect area'' to be examined annually.
NKK says this was done in may 1995, September 1995,
and the intermediate survey in ??? 1996.
No action or recommendations were made as a result of these surveys.
There was a pre-time charter survey in September 1996,
but since the bulheads had been blasted and painted,
the surveyor decided no thickness measurements were required.
When the Giga 2 reached Singapore in December,
NKK took its own set of measurements.
The measurements taken at the top of the bulkhead showed
little wastage, and those at the bottom were almost all
above the magic 13.1 mm number.
According to these measurements, the bulkhead was still legal.
Nonetheless, NKK required all the ship's bulkheads to be replaced.
It turned out from the water depths in the tanks after the collapse,
No 4 had been filled to more than 14 m.
The Australian's best guess is 17m.
NKK used some clearly specious reasoning
to conclude that it was over 18.5 m.
NKK performed an finite element analysis that
``proved'' that the bulkhead would not have failed at 14 m
but would have failed at 18 m.
Therefore the whole thing was the Chief Mate's fault.
Both the Chief Mate and a terminal superintendent
were adamant that the air-pressure based remote gauging unit
in the cargo control room showed less than 14 m.
Also there was a high level alarm set at 13 m which did not go off.
The Australians found that the gauging system was off
and believe that a small leak in the system led to the bad reading,
but they were not able to find that leak.
They faulted the CM for not checking the remote reading manually.
In CTX's view this is just another case of a marginally designed and built ship
being allowed to deteriorate by owners, class, flag state
to the point where she is patently unsafe.
If the ship had been properly designed and maintained,
she never would have had to ballast No 4.
If a hold is legally allowed to be flooded to 14 m,
then with any kind of decent safety margins,
17 or 18 meters should be no problem.
If the bulkhead had been properly maintained,
this almost certainly would have been the case.
The port states must take some blame as well.
The Australians clearly could see the steel was in very bad shape.
Providing some one who is just going down a ladder a safety rope
is extremely unusual, and I have never seen or heard of a tank worker
tieing a rope around his chest just as a precaution.
Noentheless NKK proclaimed that its inquiry had shown
that Class had done nothing wrong.
This was never really challenged.
The flag state, Malaysia, appears not to have been involved at all.
The Aussis went back to loading the next ship.
The NKK quote is a reference to the Shin Kamagawa hull failure.
Forgetting about the fact that the Shin Kamagawa
Hold 1 should not have flooded in the first place,
the quote is both specious and revealing.
It is specious in that after the Derbyshire
rules requiring the 1/2 bhd
to be specially strengthened were put in place.
Failure of 1/2 to fail does not imply
that other bulkheads wont fail.
It is revealing in that, if No 4 were designed to be flooded,
why could we assume that flooding would stop at 14 m?