Gustomsc Resources B.v.

Seaway Heavy Lifting Engineering B.v.

Willem Johannes Alain Wassink

Johan Albert Commandeur

Govert Hendrik Teunis Zijderveld

Sjoerd Maarten Hendriks

Willem Jacob Van Der Velde

The invention relates to a monohull drillship (), comprising an elongated hull () extending in the length direction () of the drillship. Said hull () is provided with at least one open moon pool () arranged to be located at the waterline () during use of the drillship. The drillship () is arranged for multiple-activity operations, e.g. simultaneous drilling and casing handling, in such a manner that drilling equipment can be passed through said at least one moon pool () at at least two locations (), i.e. at at least two so-called well centers, which are spaced apart from each other in at least a direction () substantially transverse to the length direction () of the hull of the drillship.

Monohull drillship

Vessel including a hull of a substantially closed surface has at deck level a lifting crane, ballast tanks within the hull and a ballast control unit for admitting water to the ballast tanks for changing the draft of the vessel. The hull has a narrow lower section having first width over a height from keel level to a widening level, and a top section having a larger width than the lower section, extending from the widening level upwards towards deck level. The control unit is adapted to ballast the vessel to have a relatively shallow draft level in a transit mode, so that the wide top section is above water level, while the vessel is traveling, and to ballast the vessel to a relatively deep draft level in a lifting mode so that the widening level is below water level, at least when the vessel is substantially stationary and the crane is in its lifting position.

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Vlaardingen, Netherlands

Willem Johannes Alain Wassink