Semi submersible drilling rig generation

Jackups are mobile, self-elevating drilling platforms that are equipped with moveable legs. Jackups are towed to a drilling site by tug boats before the unit lowers its legs to the seabed and then jacks up t. Semisubmersibles are classified into five generations, distinguished mainly by their age, environmental rating, variable deck load, and water-depth capability. Third-generation, conventionally-moored semisubmersibles rigs are suitable for drilling in water depths ranging from 1,200 to 3,400 feet. [pdf]