Green Marine use Orcaflex to carry out cable analyses including developing procedures and lay tables for use offshore during the deployment or recovery of a cable. These analyses are tailored to the site and environmental conditions and the deployment vessel.
As part of Microsoft’s Project Natick Green Marine were responsible for installing a 125m cable extension to an existing subsea cable. This was carried out with Green Marine’s MultiCat Green Isle. In a separate operation, the Natick device was taken to site, the cable extension was recovered and connected to the device.
In order to safely recover the existing cable and lay the extension, a lay table was developed using Orcaflex to co-ordinate the position of the vessel and the length of cable recovered/deployed. Lay tables ensure that at every stage of the recovery the cable tension is known and can be kept within tolerable limits. Exceeding these limits can result in the cable failing. The engineering team developed tables for each step of the cable handling operations.
A separate Orcaflex analysis was carried out to investigate the loads during the deployment of the connector which joined the device cable tail to the pre-laid cable extension. The engineering team developed a procedure which ensured that no twists were created between the cables during the lowering of the device.