Petrel's Mooring System Breakthrough
27 April 2006
Cape Town based Petrel Engineering was awarded a multi-million Rand contract by a Swiss company for the design and manufacture of an eight-point mooring system, hydraulic powerpacks and a knuckle boom crane.
The equipment is for installation on an accommodation barge being built for the company in a shipyard in Turkey. One of the stipulations in the scope of supply is that the mooring system will be built in class to Bureau Veritas requirements for the positioning notation POSA. Petrel completed the contract last month. The barge is destined for West Africa where it will be chartered to a major oil company to accommodate oil rig personnel. The vessel will be anchored alongside the oil rig and connected to it via a gangway. "The winches will have automatic electronic monitoring and control of tension wire length and vessel position, as extremely accurate positioning of the barge is crucial because of the close proximity of the vessel to the rig and the connecting structure", says Petrel's MD Michael Franzen. The control panel for the mooring system includes eight joysticks for individual winch control, as well as start/stop switches for the four pump motors. In manual mode it is possible to control each winch from the panels, with a readout of length and tension for each winch. In automatic mode the system monitors the rope tension and automatic haul or pay out wire on each winch to maintain tension within settable limits.
The eight winches each have a holding power of 80 tons and the pull of the 38mm diameter cable is 35 tons in auto-tensioning mode. The length of the cable on each winch is 1600 metres. The crane is used for loading and offloading goods and equipment from supply ships to the barge and then onto the rig. It is installed mid-ship and has a loading capacity of 9 tons at 13 metres. It is, therefore, capable of withstanding the impact of the dynamic loads which occur in such operations.
The mooring system and the crane are driven by two hydraulic powerpacks mounted below deck to protect them from exposure to the elements.
Franzen also adds that meeting the requirements and delivery times of, not only this project, but several others as well has indeed been a challenge. "However, the Petrel team thrive on challenges and have worked around the clock to meet these deadlines" Franzen says.
Petrel is an ISO9000 accredited company with nearly 60 years of experience in marine related industries. Petrel's standard products can be customised, in design, to clients' requirements and electrical, hydraulic and remote control systems are available for all its equipment.
