Subsea 7 Utilises Autonomous Surface Vessel in Mediterranean Pipelay Operation - 23/01/2018


ASV Global has announced the successful deployment of one of its C-Worker 7 class of autonomous surface vessels for Subsea 7. The 7m autonomous surface vessel was used to support a pipelay operation off the coast of Egypt. Fitted with a survey suite comprising a multibeam echosounder and sidescan sonar, the C-Worker 7 carried out touchdown monitoring in support of the 'Seven Antares' pipelay vessel.   

A spokesperson from Subsea 7 said the C-Worker 7 has proven to be a very capable vessel providing an excellent stable survey platform controlled by the Pipelay Vessel. Richard Daltry, technical Director at ASV Global stated his company is supporting Subsea 7 in their quest to increase operational efficiency through the use of autonomous surface vessel technology. “This operation marks a huge step in realising the potential of this technology and goes a long way to prove its operational readiness, particularly in a demanding offshore environment”, he added.

Surveying shallow waters

The C-Worker 7 operated for a total of 37 days. Use of the autonomous C-Worker 7 replaced the need for an additional survey vessel resulting in significant cost savings. The C-Worker 7 also provided greater operational flexibility due to its endurance and improved availability compared to an equivalent manned vessel. In addition, use of the C-Worker 7 resolved the technical challenge of surveying in very shallow waters whilst also removing the risk to personnel working at sea in small craft.  

Sensor calibrations

A custom payload frame was designed to house the specified survey suite. The modular frame slotted into the C-Worker 7’s moonpool to mount and deploy the sensors. Extensive testing confirmed that repeated sensor deployment was achieved within millimetre accuracy ensuring that no further survey sensor calibrations were required. Vessel trials and testing took place in the Solent, UK before the vessel was mobilised from ASV’s UK headquarters.

Throughout the operation the C-Worker 7 was controlled and monitored using the ASView control system from a control station set up onboard the Seven Antares. Subsea 7 Survey personnel piloted the C-Worker 7 and operated the survey sensors to ensure data accuracy and quality.

Last updated: 13/12/2018