Case Study 2470 Dry Tow

Sedco 709 Dry Tow

Rig Name: Sedco 709
Rig Type: Semi-Submersible
Owner name: Transocean
Classification Society: ABS
Pertinent code: Sname
Pertinent code: ABS Modu

Model 3D
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Project description
Structural assessment for moving Sedco 700 and Sedco 709 in tandem, on board Dockwise’s Blue Marlin Vessel was undertaken for dry tow purpose to repair facility in Far East. Additional assessment was also made to put Sedco 709 on repair barge on route to South Africa protected water where the Special Periodical Survey and associated repair was conducted. Operating and storm condition were checked in accordance with owner and warranty surveyor’s requirements.

FEA Model


R.E. Scope of work
Rig Engineering was tasked with screening of suitable barge, vessel and dumb barge for the use of construction / repair works and dry tow purpose leading to final assessment and sea fastening of vessel to deck. FEA model of the hull, column and bracings were made and loaded with local and global loads provided by owners and barge’s owners. Strength check of internal dividing bulkhead, ring frame, all major structural connection were done and suitable cribbing plan issued for construction. Reactions to deck were supplied to barge owners and dry transporting company, for structural adequacy check on their vessels. Technical reports were then submitted to owners and class as required.
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1. As built of structure to create 3D FEA model.
2. Static and environmental loads of rig.
3. Barge detailed information and stability characteristic.
Key word: Sedco 709 Rig Engineering, dry tow, semi sitting on repair barge, pontoon strength check, hull blocking assessment, global strength check R during tow and storm condition while on transportation vessel, barge or repair barge