Transshelf loaded with the jack-up rig Constellation I ready for departure

Project Summary

The GlobalSantaFe jack-up rig Constellation I needed to be moved from its construction yard in Singapore to Trinidad. Because of the long legs (167 m), the dry transport option was selected with its inherent higher transit speed and reduced motions in seaways. Since this would be the first time a Friede & Goldman JU 2000 class rig was dry transported and the stability after loading was marginal, it was considered prudent to have a qualified naval architect on site in case the actual numbers would show a significant deviation from the theoretical numbers.

On March 22, 2004, the rig was towed to and accurately positioned over the submersed heavy-lift ship Transshelf. The ship slowly deballasted, and with a controlled small trim and list, the 19,000 t heavy Constellation I was slowly lifted out of the water. The final sailing condition showed adequate stability and after seafastening of the rig, the ship departed.  

Scope of Work

The project scope included:

• Provide design environmental criteria for the transport;

• Verify transportation weight and center of gravity in office, and on-site;

• Study sensitivity of VCG variations on the stability of the heavy-lift ship;

• Simulate deballasting operation with varying trim conditions;

• Standing by on-site during the actual load-out of the rig.

Project Photographs

Heavy-lift ship Transshelf submersed and ready to receive the rig.	Constellation I slowly towed towards the Transshelf using local tugs.	Rig bow slowly rises out of the water when the ship is deballasted.	After loading, the rig is seafastened for the voyage.