Danube River Salvage Project- 6500 CBM LPG Vessel Re-launch
admin:admin time:2011-09-13
On Sep. 2 Eversafe Marine Engineering company successfully re-launched a 6500 m3 LPG Vessel with marine airbags (ship launching balloons) in a Romanian shipyard.
Project information :
That vessel measures by 116 m long and 18 m wide with 3650 tons light weight plus 450 tons ballast water.
Something wrong happened to the 6500 m3 LPG Vessel side launching. That vessel stranded in Danube river, partly on slipways and broken slipping sledges. The vessel gets 9 degree transverse inclination and 1 degree inclination in lengthways direction. The heights from ground to vessel bottom are 0.3-0.8 m. The existed 25 cm high slipways have 8 m center spaces. In high tide time the water can reach 2.7 m and 0.7 m high respectively at vessel stern and bow.
Difficulties:
The vessel sits on slipways and broken slipping sledges with inclinations in two directions that is the main difficulty. To be worse vessel has very narrow bottom shape. Broken wood and flat bar in the space of slipways are absolute menace to rubber air bags. The water carry lots of mud to vessel neighborhood everyday which also make troubles for the project. To re launch vessel with slipway by side launching method people need to replace damaged slipways when vessel is lifted. It will take more than three weeks to finish the replacement or reparation work since most works have to be done in limited space (under vessel ) underwater. If people try to re launch vessel in lengthways direction the slipways are obstacles for airbag rolling. Also the landform in vessel lengthways direction is not good for airbag ship launching.
Plan:
To re-launch the vessel people need to remove all broken sledges first. Marine airbags are the ideal tool to lift vessel to do the cleaning job since they have huge contact area with vessel and can be installed easily. According to calculation total 26 pieces marine airbags will lift vessel and adjust vessel to be parallel to slope. Since vessel have inclinations in two directions winches will be employed to fix vessel in two directions.
When vessel is lifted by airbags people can replace broken sledges and slipways for the launching or launch it with rolling airbags. Comparing with other re-launching plans shipyard thinks using airbags to roll vessel out is the best choice because it saves most time and money. Pulling force will surely be needed to make vessel move in lengthways direction. To enable airbags can roll over slipways and ensure no slipway breakage Eversafe engineers made an ingenious design which employing sand sacks to stuff ground and slipways.
Perform:
In seven days Eversafe Marine delivered 26 pieces marine airbags which were transported to Romania by air. Eversafe engineers arrived at shipyard at August 21. Winches were first installed to fix vessel in two directions. It took seven days to lift vessel and remove all broken sledges from vessel bottom. Some practical difficulties slow down the process: incline vessel bottom made it difficult to install airbags in right position; limited space and mud baffled people to do cleaning.
When finishing the cleaning job people began to stuff ground under vessel and future launching area with sand sacks and steel plates. It is another hard working because of the water and mud. To get a 150 tons pull force shipyard combined a tug with bulldozer with pulleys. When the preparation work was ready pull back winches were removed. At that time the vessel was steady on airbags which agreed with calculation well.
At 7 P.M. of Sep. 2 the re-launching work started. With increasing pulling force the vessel began to move in lengthways direction very slowly. Marine airbags rolled forward arduously at the beginning. About three or four minutes later vessel’s stern began to slip from airbags at the same time vessel moved forward post. Soon vessel’s stern got floated but bow was still riding on airbags. At last vessel floated totally. From pulling start to vessel float the whole process took about 10 minutes.
It is a hard project. Every forward step need careful design and hard working. From shipyard people to Eversafe engineers all people did a good work. This special project of marine airbags re-launching a vessel from a 7 degree slope which full of sand sacks and woods gives people illumination for marine salvage works.
The famous “Blue Danube” song sings,
Young blood
fresh courage,
O how happy,
it unites laughter!
Love and passion
fills the breast --
it's the greatest in the world.
That is exactly what we want to say for this Danube salvage project.
