Page 87 - 6634

Figure 6.8 - Relative hull responses of the three designs

During the concept selection phase, efforts are concentrated on the main

dimensions and weights under the consideration of design standards and

performance requirements without a high degree of engineering detail. Finalized

dimensions and main properties of the floating structures will be determined in the

front-end engineering and design (FEED) stage through various analyses.

Floating drilling vessels are classified in two basic categories: (1) ship

shape, e.g., drillships with hulls similar to ships and barges that are self- propelled
or towed to location and (2) semisubmersibles (semis) (fig. 6.9).

6.2.1 Semi-submersible platforms

Concerning the group of the mobile offshore structures, the semi-
submersibles can be considered as typical offshore units .

87