MV Rocknes
Encyclopedia
M.V. Rocknes was a 166 metres (544.6 ft)-long rock discharge vessel that hit a shallow and suddenly capsize
d south of Bergen, Norway, killing 18 members of its 30-person crew. At the time of its sinking, it was the worlds largest dynamically positioned flexible fall pipe rock dumping vessel. The ship was repaired during 2004 and 2005 and renamed Nordnes.
”Rocknes” was owned by Kvitnes Shipping Company Ltd. of St. Johns, a part of the Hartmann group of Cadenberge, Germany. The ship was on a long-term charter
to Van Oord ACZ, an international contractor specializing in dredging, rock dumping, and offshore and coastal construction.
, The Netherlands. The actual conversion was led by a design team formed by Van Oord ACZ. Post-conversion, the ship remained a capable bulk carrier, albeit with a 3000 MT (2,952.6 LT; 3,306.9 ST) reduction in cargo capacity and a loss of 0.6 kn (1.2 km/h; 0.73067287043665 mph) of sailing speed.
Conversion was scheduled for a maximum of 112 days, and was completed in 124 days, 12 days later than planned.
In order to create an economically feasible vessel of this size, the vessel must be designed with a high deadweight tonnage
and a relatively high sailing speed to allow large quantities of rock, with densities ranging from 1.4 MT (1.4 LT; 1.5 ST) per cubic meter or 1.1 MT (1.1 LT; 1.2 ST) per cubic yard, to be rapidly transported to deeper waters farther from shore.
Because of the density of the rock, the ship must include large void spaces located ahead of, astern of, and to either side of the cargo holds in the hull to provide sufficient buoyancy
.
The holds themselves are loaded from above through hatch
es by shore-based equipment. They are designed with sloping sides and bottoms to allow them to be self- and self-unloading via a conveyor belt
running the length of the holds along the centerline of the ship at their lowest point.
The conveyors transport the rock to the forward part of the ship, into a rock hopper, then into flexible fall pipes that extend out of the ship's bottom through a moon pool
. The ends of the fall pipes are fitted with purpose-built, state of the art remotely operated vehicle
s (ROVs) which ensure that the fall pipes are accurately guided along the cable or pipeline, ensuring highly precise deposition of protective rock ballast. These ROVs can also be used for dredging
, trench
ing, and jetting tools.
The large quantity of heavy equipment mounted above the main deck of the ship raises its center of gravity
and reduces its transverse stability.
d south of Bergen, Norway
, killing 18 of 30 crew.
by Blueprint for Disaster
Capsize
Capsizing is an act of tipping over a boat or ship to disable it. The act of reversing a capsized vessel is called righting.If a capsized vessel has sufficient flotation to prevent sinking, it may recover on its own if the stability is such that it is not stable inverted...
d south of Bergen, Norway, killing 18 members of its 30-person crew. At the time of its sinking, it was the worlds largest dynamically positioned flexible fall pipe rock dumping vessel. The ship was repaired during 2004 and 2005 and renamed Nordnes.
”Rocknes” was owned by Kvitnes Shipping Company Ltd. of St. Johns, a part of the Hartmann group of Cadenberge, Germany. The ship was on a long-term charter
Charter
A charter is the grant of authority or rights, stating that the granter formally recognizes the prerogative of the recipient to exercise the rights specified...
to Van Oord ACZ, an international contractor specializing in dredging, rock dumping, and offshore and coastal construction.
Conversion
Conversion of the ship was commissioned on 3 May 2003 in response to the increasing demand for offshore rock dumping. The ship was converted from the self unloading bulk carrier M.V. Kvitnes at Keppel Verolme Shipyard, BotlekBotlek
thumb|right|[[Satellite]] [[image]] of the [[Rhine]]-[[Meuse River|Meuse]] [[river delta|delta]] showing the Botlek .The Botlek originally was the name of a stretch of the Nieuwe Maas river, part of the Rhine-Meuse delta near the Dutch cities of Vlaardingen and Spijkenisse in the province of...
, The Netherlands. The actual conversion was led by a design team formed by Van Oord ACZ. Post-conversion, the ship remained a capable bulk carrier, albeit with a 3000 MT (2,952.6 LT; 3,306.9 ST) reduction in cargo capacity and a loss of 0.6 kn (1.2 km/h; 0.73067287043665 mph) of sailing speed.
Conversion was scheduled for a maximum of 112 days, and was completed in 124 days, 12 days later than planned.
Design challenges
Its large size (largest in the world at the time of its construction) created unique design challenges.In order to create an economically feasible vessel of this size, the vessel must be designed with a high deadweight tonnage
Deadweight tonnage
Deadweight tonnage is a measure of how much weight a ship is carrying or can safely carry. It is the sum of the weights of cargo, fuel, fresh water, ballast water, provisions, passengers, and crew...
and a relatively high sailing speed to allow large quantities of rock, with densities ranging from 1.4 MT (1.4 LT; 1.5 ST) per cubic meter or 1.1 MT (1.1 LT; 1.2 ST) per cubic yard, to be rapidly transported to deeper waters farther from shore.
Because of the density of the rock, the ship must include large void spaces located ahead of, astern of, and to either side of the cargo holds in the hull to provide sufficient buoyancy
Buoyancy
In physics, buoyancy is a force exerted by a fluid that opposes an object's weight. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus a column of fluid, or an object submerged in the fluid, experiences greater pressure at the bottom of the...
.
The holds themselves are loaded from above through hatch
Trapdoor
A trapdoor is a door set into a floor or ceiling .Originally, trapdoors were sack traps in mills, and allowed the sacks to pass up through the mill while naturally falling back to a closed position....
es by shore-based equipment. They are designed with sloping sides and bottoms to allow them to be self- and self-unloading via a conveyor belt
Conveyor belt
A conveyor belt consists of two or more pulleys, with a continuous loop of material - the conveyor belt - that rotates about them. One or both of the pulleys are powered, moving the belt and the material on the belt forward. The powered pulley is called the drive pulley while the unpowered pulley...
running the length of the holds along the centerline of the ship at their lowest point.
The conveyors transport the rock to the forward part of the ship, into a rock hopper, then into flexible fall pipes that extend out of the ship's bottom through a moon pool
Moon pool
A moon pool is a feature of marine drilling platforms, drillships and diving support vessels, some marine research and underwater exploration or research vessels, and underwater habitats, in which it is also known as a wet porch...
. The ends of the fall pipes are fitted with purpose-built, state of the art remotely operated vehicle
Remotely operated vehicle
A remotely operated vehicle is a tethered underwater vehicle. They are common in deepwater industries such as offshore hydrocarbon extraction. An ROV may sometimes be called a remotely operated underwater vehicle to distinguish it from remote control vehicles operating on land or in the air. ROVs...
s (ROVs) which ensure that the fall pipes are accurately guided along the cable or pipeline, ensuring highly precise deposition of protective rock ballast. These ROVs can also be used for dredging
Dredge
Dredging is an excavation activity or operation usually carried out at least partly underwater, in shallow seas or fresh water areas with the purpose of gathering up bottom sediments and disposing of them at a different location...
, trench
Trench
A trench is a type of excavation or depression in the ground. Trenches are generally defined by being deeper than they are wide , and by being narrow compared to their length ....
ing, and jetting tools.
The large quantity of heavy equipment mounted above the main deck of the ship raises its center of gravity
Center of gravity
In physics, a center of gravity of a material body is a point that may be used for a summary description of gravitational interactions. In a uniform gravitational field, the center of mass serves as the center of gravity...
and reduces its transverse stability.
Sinking
MV Rocknes hit a shallow and suddenly capsizeCapsize
Capsizing is an act of tipping over a boat or ship to disable it. The act of reversing a capsized vessel is called righting.If a capsized vessel has sufficient flotation to prevent sinking, it may recover on its own if the stability is such that it is not stable inverted...
d south of Bergen, Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...
, killing 18 of 30 crew.
In the media
The sinking of the Rocknes was broadcast on Discovery ChannelDiscovery Channel
Discovery Channel is an American satellite and cable specialty channel , founded by John Hendricks and distributed by Discovery Communications. It is a publicly traded company run by CEO David Zaslav...
by Blueprint for Disaster
Blueprint for Disaster
Blueprint for Disaster is a Canadian documentary television series that premiered in 2004 on Discovery Channel Canada. Produced by Temple Street Productions, the program investigates why and how various disasters have happened. Toronto-based Voice Artist Adrian Bell provided the narration for the...
External links
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- The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.