Gorgon Umbilical Crossing Turning Bollards

Location: Karratha, Western Australia

Client: Chevron Australia

Contractor: Subsea 7

Scope of Work: Provision of Umbilical Turning Bollards


Subcon was subcontracted by Subsea 7 to provide eight 3 Tonne Umbilical Turning Bollards. These curved bollards were bespoke designs produced by the Subcon design team in Perth.

The bags were manufactured in our Perth facility and pre-filled with grout prior to being deployed using an ROV operable lift frame, which was also designed by Subcon engineers. The bags were allowed to free-flood during deployment so that the grout would set post setdown.

Subcon supplied eight custom designed grout bag deflectors and a certified lifting frame suitable for subsea installation of the bags by ROV. The bags were manufactured with a built-in radius of 10.5m to match the minimum bend radius (MBR) of the umbilical. The frame was designed to match the MBR and facilitate rapid release by the ROV.

Subcon manufactured a total of ten bags to allow for proof loading and break load testing of two units by a NATA approved test facility. The bags were then delivered, pre-filled with cement, to reduce handling and offshore deployment time. Traceability was maintained by assigning the bags with batch numbers that corresponded to the test samples. The bags were manufactured from UV stabilized, high tenacity, PVC laminated, polyester scrim. One way, flush mounted boat valves were used to seal the bags for transport in order to prevent the egress of cement dust and ingress of moisture until the bags were deployed. The valves were opened prior to deployment to allow flooding and subsequent setting of the cement.

“It becomes a real benefit to us when suppliers like Subcon can take some of our issues off our hands for us and provide a solution, not just a product”;

Subsea7.

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