DRY DOCKING FALRIG 77 AND FALRIG 78

Project Summary

With limited dry dock capability in the Gulf of Mexico, the possibility of dry docking the submersible drilling rig FALRIG 77 on a

Crowley 400 class submersible barge was investigated. Given the draft of the rig, including its mud skirt, the required barge

submersion draft was well over its original design limit. Structural analysis of the barge bulkheads however showed that the barge

could safely be submersed to the required draft. Structural analyses of the barge deck and rig bottom frames showed that the

cribbing block loads were acceptable.

Late December 1996, the FALRIG 77 was loaded onto the BARGE 400-7 in Mobile, Alabama, for maintenance and repair of the mat

structure. Upon completion of the work, the rig was safely lowered back into the water and floated off.

The project scope included:

This project was a joint venture between Argonautics Marine Engineering, Inc. and Technical Salvage Advisors, Inc. After successful

completion of the FALRIG 77 dry docking, Falcon Drilling Company decided to also dry dock its rig FALRIG 78.

specialists in marine heavy-lift transportation engineering

naval architects

marine surveyors

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Est. 1992

■	Structural analysis barge bulkheads, subjected to hydrostatic pressure;
■	Structural analysis barge main deck, subjected to large local block loads;
■	Design cribbing arrangement, using available wood blocks;
■	Structural analysis of rig bottom frames, subjected to large block loads;
■	Structural analysis of the unsupported rig overhang;
■	Design ballast procedures for loading and offloading;
■	On-site assistance during the offloading of the rig.

Drilling rig FALRIG 78 after completion of repairs ready to be lowered back into the water

Cribbing blocks

Detail rig mat overhang

Ballasting barge under water

Rig floated off and towed away