6. Catamaran Floatover

When the platform substructures do not have openings wide enough for installation vessels to move in, catamaran floatover method is the choice of platform integration. Two floatover vessels and the topsides form a catamaran. The mating operation procedure are the same as the HIDECK, except the involvement with two vessels. Catamaran floatover methodology has been successfully applied in both inshore and offshore platform integration. In general, the catamaran is formed at the location near the mating site, therefore the topsides will be transported from the yard to the selected location by a third vessel and then the topsides is transferred to the floatover vessels. This extra step operation need to be well prepared through intensive engineering efforts. Discussion in this chapter covers the operation details with the examples of CGBS inshore integration and the spar offshore integration. For these operations, floatover vessels do not need specially designed equipment besides grillages and sea-fastenings. Two other catamaran floatover methods using special equipment: the Versatruss and TML methods are also presented in this chapter.