The boom in oil and gas field development has dramatically increased the demands for drillships.
Drillships have a moonpool in the center area of the ship for the purpose of drilling.
A moon pool also allows divers or small submersible craft to enter or leave the water easily and in a more protected environment.
Moonpools originated in the oil drilling industry, which uses them in drilling at sea or in lakes, to pass drilling equipment into the water from a platform or drillship. Drill pipes need to run vertically through the structure or hull, and the moon pool provides the means to do this.
This moonpool has an effect on the seakeeping performance of a drillship in the vicinity of the resonance frequency.
Because of the moonpool, drillships act in different resonance modes, called the sloshing mode and piston mode.
Moonpools are constructed in different shapes including circles, squares, rectangles and so on.
Among the different shapes of moonpools, rectangular shaped moonpools with and without a cofferdam are common in recently constructed compact drillship.