The winches have three different operating modes:
1. Tugger (horizontal heaving/lowering) with a 20 ton capacity
2. Constant tension (CT) with a 20 ton capacity
3. Lifting with a 12.5 ton capacity
For the CT mode an accuracy of +/- 5% (of the maximum pulling force) is required. The CT mode must also have a load limit function with a required accuracy of +/- 5%. The heaving pulling power can be set at a lower value than the lowering pulling power within this context. A wireless remote control panel is used for its operation. The panel has joysticks. This ensures that the speed of the two winches can be infinitely controlled between 0 and 18 m/minute on the first layer. The winches must also be equipped with load pins. They are required to measure the true pulling power in the cable and to display this on a display.
The winches are intended for installation on-board the Aegir Deepwater Construction Vessel. The winches are used to assist a load in the Aegir’s main crane. This may sometimes be for positioning offshore installations and systems. At other times, they may be used to handle deck equipment. An application can be: One of the winches is switched to the tugger mode. The other winch is placed opposite this in the CT mode. The load can be moved to and fro with a joystick using the tugger winch. The CT winch will ensure a constant tension in the cable. The winch must lower when the pulling force in the cable becomes higher than the set load limit value because of an (external) load.
For this project, Hydrauvision based itself on winches based on hydraulic motors of the Hagglunds Viking type. These hydraulic motors have a high mechanical performance, which means that the required CT accuracy can be achieved relatively easily. Both winches have advanced PLC control that is used to operate all requested functions.
The required safety aspects have been taken into account in the design. They mainly play an important part with regard to lifting winches. The load pins are installed in the winch bases. They provide feedback to the PLC about the true pulling force. This controls the pulling power accurately using proportional pressure-controlling valves. Hydrauvision developed a radio-controlled control panel for the central control. Both winches can be operated and controlled simultaneously with this. The winches are equipped with Lebus split sleeve drums. This is a patented groove pattern where the cables run in parallel for approximately 70% of the rotation. This in contrast with drums with conventional spiral grooves. The winches are equipped with removable protection panels for the sake of safety.