The gravity base

The gravity base is a rectangular, cellular-reinforced, concrete structure which, in this example, comprises four separate ballast compartments. The gravity base is designed to sit on the seabed, and to resist the uplift and lateral forces imposed by the Buoy, umbilicals and tethers. A short steel skirt may be fitted to increase the sliding resistance of the base on the seabed.

Other typical specifications are as follows. Dry weight of 2,800 tonnes; size of 20 metres square and 7.5 metres high. The specification is determined by the requirements outlined above.