Passive damping lifts support vessel safety
The SE Hydraulics damping systems enable ARRCs to be deployed quickly and safely, often in very harsh operating conditions.
Specialised UK engineering company SE Hydraulics and American motion and control specialist Parker Hannifin have partnered to develop a passive damping system to protect crew members on Regional Support Vessels.
Used in conjunction with the davit mechanisms on each of four RSVs, the damping systems enable Autonomous Rescue Recovery Craft (ARRCs) to be deployed quickly and safely, often in very harsh operating conditions.
The multi-role RSVs are used as part of BP’s North Sea operations to deliver essential supplies of food and fuel to the production and drilling rigs, to remove waste, and to provide critical safety cover.
A key factor in the operation of the ARRCs is the ease with which they can be launched, with specially designed davit systems enabling them to deployed quickly in seas of up to 7m. Unlike lifeboat davits on most vessels, those on the RSVs are in regular use, so have to withstand considerable wear and be easy to maintain in particularly harsh operating environments.
The passive damping systems developed by SE Hydraulics with support from Parker effectively prevent harmonic oscillations from occurring by using two mechanical arms or fingers per ARRC. These arms form an integral part of the launch system and face outwards onto the inflatable sponson of the ARRCs, providing resistance to the rolling motion and rising and falling as each ARRC is deployed or recovered.
Chris Blevins, director of SE Hydraulics, explained, ‘There is a self contained passive damping systems for each of the two ARRCs on every Regional Support Vessel. We have used Parker hydraulic components throughout, with each mechanical arm being controlled by a directly connected and vertically mounted pair of cylinders, linked back to twin accumulators mounted within a compact hydraulic and electrical control module on a lower deck. This design allows pressure to rise and fall in a carefully controlled manner, with the force on each side of the cylinder, and therefore on the position of the arm, being regulated by the accumulators to provide a balancing resistance against the rolling action of the ARRCs as they are suspended in the davit falls.’
The first of the damping systems, fitted to the Caledonian Vigilance, have now been operating successfully for over two years in the extremely harsh conditions of the North Sea.
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