Jack-up vessel “Vidar”, Germany

The ship converts into a jack-up platform due to the hydraulic lowering of four movable legs with a length of 90 m and a diameter of 4.80 m. The jack-up system can lift a total weight of 25,000 t out of the water. It consists of 48 corrosion-resistant cylinders delivered by Montanhydraulik, the respective rig fixation systems and guide frames as well as the corresponding electrical control system.

The hydraulic construction is characterised by two mobile guide frames per leg, which are positioned opposite one another. Their movement is regulated by means of synchronous control. Muns Techniek developed the control system in order to ensure the synchronous lifting and lowering of the four legs via the necessary lift, without the platform having to be stopped for the fixation procedure.

Six cylinders respectively move via the frames, each of which has a diameter of 800 mm and a length of between 7.40 m and 10.40 m, weighing about 22 tons. At a nominal pressure of 350 bar the cylinders develop a tensile force of 14,000 kN.

The legs of the jack-up vessel are extended to the sea bed at a speed of 1 m/min. In doing so, the hydraulic system not only provides the lifting function, but also a high degree of insensitivity of the ship to impacts. As soon as all four legs reach firm ground, the ship lifts itself out of the water.

Hydraulics: Hydraulic cylinders:
  • hydraulic performance: 8,500 kW
  • max. oil flow: 18,000 l/min
  • operational pressure: 320 bar
  • 48 traction cylinders: 800 x 360 x 3,000 mm
  • max. cylinder speed, leg up/down, floating: 1.2 m/min
  • max. cylinder speed, leg up/down, floating: 1 m/min
  • piston rod coating: ceramic with integrated displacement measurement system