Interesting findings in that 12 container ships have been pinpointed as likely to have the same failure as the Napoli.
Synopsis:
During the morning of 18 January 2007, when on passage in the English Channel, the
4419 TEU container ship MSC Napoli encountered heavy seas, causing the ship to pitch
heavily. The ship was making good a speed of 11 knots and the height of the waves was
up to 9m. At about 1105, the vessel suffered a catastrophic failure of her hull in way of her
engine room. The master quickly assessed the seriousness of the situation and decided to
abandon ship. Following the broadcast of a distress call at 1125, the 26 crew abandoned the
vessel in an enclosed lifeboat. They were later recovered by two Royal Navy helicopters.
There were no injuries.
MSC Napoli was subsequently taken under tow towards Portland, UK but, as the disabled
vessel approached the English coast, it became evident there was a severe risk she might
break up or sink, and she was intentionally beached in Branscombe Bay on 20 January 2007.
A number of containers were lost overboard when the vessel listed heavily after beaching.
The investigation has identified a number of factors which contributed to the failure of the hull
structure, including:
• The vessel’s hull did not have sufficient buckling strength in way of the engine room.
• The classification rules applicable at the time of the vessel’s construction did not
require buckling strength calculations to be undertaken beyond the vessel’s amidships
area.
• There was no, or insufficient, safety margin between the hull’s design loading and its
ultimate strength.
• The load on the hull was likely to have been increased by whipping effect.
• The ship’s speed was not reduced sufficiently in the heavy seas.
In view of the potential vulnerability of other container ships of a similar design, the MAIB
requested the major classification societies to conduct urgent checks on the buckling strength
of a number of ship designs. Over 1500 ships were screened, of which 12 vessels have been
identified as requiring remedial action; a further 10 vessels were identified as being borderline
and require more detailed investigation; and the screening of 8 container ships was still in
progress at the time of publication. Remedial action has either been completed, planned,
or is being arranged; where necessary, operational limitations have been agreed or strongly
advised until the remedial work has been completed.
Recommendations have been made to the International Association of Classification Societies,
which are intended to increase the requirements for container ship design, consolidate
current research into whipping effect, and to initiate research into the development and use
of technological aids for measuring hull stresses on container ships. Recommendations have
also been made to the International Chamber of Shipping with the aim of promoting best
practice within the container ship industry, and to Zodiac Maritime Agencies, with reference to
its safety management system.
Full Report:
http://www.maib.gov.uk/publications/inv ... napoli.cfm