The and the topsides of the Perdido were constructed separately and then assembled in its final position in the Gulf of Mexico. The Perdido's hull or spar was constructed by in . A barge shipped the 22,000 tonne spar 13,200 kilometres (8,200 miles) from the to the Gulf of Mexico. After floating the spar, it was towed to its final home above the Alaminos canyon 320 kilometres (120 miles) fr.
[pdf] Located approximately 196 miles east of Newfoundland, Canada, the Hibernia rig is the world’s largest offshore rig and the first iceberg-resistant gravity structure. It operates in the North Atlantic with a total tonnage of 496,040 tons.
[pdf] 
A drillship has greater mobility and can move quickly under its own propulsion from drill site to drill site in contrast to semi-submersibles and jackup barges and platforms. Drillships have the ability to save time sailing between oilfields worldwide. .
A drillship is a merchant vessel designed for use in exploratory offshore drilling of new oil and gas wells or for scientific drilling purposes. In recent years the vessels have been used in deepwater and ultra-deepwater. .
A drillship can be used as a platform to carry out well maintenance or completion work such as casing and tubing installation, subsea tree installations, and well capping. Drillships are often built to the design specifications set by the oil production. .
There are different types of units such as the , , , platform and of course drillships. All drillships have what is called a ”moon pool”. The is an opening on the base. .
The first drillship was the , designed by Robert F. Bauer of Global Marine in 1955. The CUSS I had drilled in 400-foot-deep waters by 1957. Robert F. Bauer became the. .
Drillships are just one way to perform various types of drilling. This function can also be performed by , jackups, .
• • • • •
[pdf] 
