OCS entered the Offshore Wind (Renewable sector) with the Tra Vinh Project in Mekong River Delta, Vietnam for the client ‘Vestas’. OCS was appointed as the contractor responsible for overseeing the overall installation of the wind towers in the intertidal zone (2m to 6.5m) including Construction Management (including Barge rig up), Engineering and Offshore Execution.
OCS scope included the concept study and selecting of the suitable lifting crane. In this case it was concluded that a single boom crane (boom length 126m) was best suited for the purpose owing to the risk of transporting a dual boom crane. The highest lift was 170mT (Nacelle + Hub) at a height of 110m above sea level
OCS was also responsible to identify a suitable barge for this intertidal zone, where the water depth changes from 2m to 6.5m. In this case Crowley HDB 402 (400ft x 120ft x 25ft) barge was chosen based on its ability to ground when required, ballastable with a side sea chest which also aids in grounding, the high barge depth to cater for higher water depths and the length to cater for the long boom crane. An eight point mooring was designed, procured and rigged up on the barge by OCS.
OCS owned multicat shallow water tug complimented the barge as she was able to carry out the anchor handling operations upto a minimum water depth of 2.5m water depth which reduced the tide dependent down time to a large extent.