Vosta Launches Dredge in Singapore on Ship-Launching Airbags
In October 2013 Vosta LMG B.V. launched cutter suction dredge Cassiopeia V at ASL shipyard in Singapore for Japanese dredging company Penta-Ocean Construction Co. Harking back to the days when ships were rolled of the slipway on wooden logs the dredge was launched on large rubber tubes known as ship launching airbags.
Vosta Project Manager Chris Roodenberg said the airbags have an advantage because they’re easy to transport and position when empty. Once in place they are inflated to lift the vessel from its docking blocks or cradles. By adjusting air volume and pressure operators can adapt them to the ship’s weight and height. Roodenberg said rubber also has the advantage because it is soft and won’t damage hull bottoms and coating systems.
Approximately 10 launching airbags were used for Cassiopeia V with additional bottom plates in the ladder well and spud carrier to prevent the airbags from getting trapped or damaged.
Cassiopeia V is s self-propelled cutter suction dredge with a flexible spud carrier system anchor booms barge loading installation and a traveling deck crane. It has three dredge pumps – one single-walled on the cutter ladder and two double-walled inboard. The suction diameter is 900 mm (35 inches) and the discharge diameter is 850 mm (33.5 inches).
It is diesel electric driven and propelled by two azimuth thrusters. Roodenberg said the power distribution is very flexible. “When the vessel is dredging the electric power can be used for the dredging equipment. While sailing this power can be used for propulsion. Furthermore electric motors can supply high torque at low speed” he said.
The azimuth thrusters are propeller units that can rotate 360 degrees at maximum thrust. Roodenberg said this makes the vessel very maneuverable. Because the thrusters are driven by electric motors the main generator engines can feed them. They can also be disassembled while afloat for repairs.
Cassiopeia V has a dredging depth of 32 meters (105 feet).
The dredge will work internationally. Roosenberg said Penta-Ocean has a strong market position in Far East Asia. The self-propelled dredge can mobilize easily over deep waters. It is designed for cutting compacted sand and rock. It can pump sediments through a pipeline for reclamation work at large distances and into hopper barges.
