M.V. Rocknes was a 166-metre rock fallpipe ship. Rocknes was on a long-term charter to Van Oord ACZ.
It capsized, after hitting a shallow spot, on January, 19th, 2004, south of Bergen, Norway, killing 18 members of its 30-person crew.
The ship was converted from the self unloading bulk carrier M.V. Kvitnes at Keppel Verolme, The Netherlands. During the conversion some 3000 ton steel was added, which heightened the ship's centre of gravity.
MV Rocknes hit a shallow and capsized within seconds, south of Bergen, Norway. Capsizing of M.V. Rocknes, photos taken in a timeframe of a few seconds.
MV Rocknes hit a shallow and capsized within seconds, south of Bergen, Norway.
Capsizing of M.V. Rocknes, photos taken in a timeframe of a few seconds.
ROOT CAUSES OF THE ACCIDENT
More insight on the stability of the Rocknes can be found in Non-official comments
The root causes of the accident can be summarised:
1. Stability: Rocknes had a too low initial metacentric height, although the vessel was loaded to its marks. The low metacentric height is believed to origin from using a too high density for the cargo of rock (see official report and Non-official comments). Rocknes' stability was a major issue, seen the retrofit with a large deck construction.
Personal note: if density of the cargo was so important, it could have been measured by taking the ullages of the cargo in the holds. The stones were sometimes sprayed with water prior to loading, sometimes not... The grades of stone varied.... All this indicates a variable cargo density. Reasons enough to measure cargo density, since stability was critical.
2. Manoeuvrability: since Rocknes left port with a too low metacentric height (meaning: unstable; not seaworthy), the vessel had a poor course stability. This was known among the local pilots, and they acted accordingly, commanding only small rudder angles.
3. Pilotage: Rocknes needed to make a tight passage at Vatlestraumen. This change of course was performed less than perfect, and Rocknes strayed to one side of the channel and hit a shallow spot.
4. Hydrographics: the shallow patch was found recently, during a hydrographic survey, and assessed to be dangerous. The design on the nautical charts was changed to reflect the new assesment. This information was not broadcasted properly, and old charts were still used on Rocknes.
The dangerous situation was also hard to spot on the scale used on this chart. All details were displayed within a few millimetres. Rocknes had a ship's breadth to spare with a normal passage.
5. Damage stability: two ballasttanks were ruptured, and one slightly holed. There is discussion if Rocknes would have capsized with this damage, provided a better initial stability.
Sure thing is that the ship would have taken longer to capsize, hence more chances to warn crew and to save lifes.
More data can be found on: http://epub.sub.uni-hamburg.de/epub/volltexte/2008/1798/
Rocknes was pushed towards a shallow part, to prevent it from sinking. Four crewmemebrs were rescued by opening the hull with cutting torches.
The vessel was later uprighted by pulling with winches from shoreside. After the succesful salvage, Rocknes was towed to Remontowa shipyard in Poland, repaired, and returned to service again as fallpipe vessel Nordnes.
All details of the salvage can be found on: http://www.rocknessalvage.com/rocknes/default.asp.
Nordnes, back in service.
Marc Van de Velde