Abstract: A bell design crown block for a top mounted compensator includes a removable, tilting sheave block mounted within the outside perimeter of a crown block yoke. An actuator installed in the crown block actuates the tilt function. No hinge adaptor is required and the sheave block does not hang past or below the crown block yoke. When used in a floating platform application, idler sheaves are mounted on the crown block yoke and an optional interface beam may be provided for the active heave cylinder head.

Abstract: A drilling system comprises a drilling vessel comprising a rig floor, a derrick extending from the rig floor of the drilling vessel along a longitudinal axis. The derrick comprises a first end disposed at the rig floor and a second end longitudinally spaced from the first end, and a heave compensation system disposed at the second end of the derrick. The heave compensation system comprises a support structure comprising a first laterally extending frame coupled to the second end of the derrick, and a second laterally extending frame spaced from the first frame, a crown block coupled to the support structure and a transport assembly coupled to the second frame of the support structure. The transport assembly comprises a first lifting lug and a cylinder assembly supported by the first frame, wherein the cylinder assembly is releasably coupled with the crown block and configured to longitudinally displace the crown block relative to the support structure in response to a heave movement of the vessel.

Abstract: A method for removing a component of a heave compensation system includes decoupling a cylinder assembly from a crown block, the cylinder assembly configured to displace the crown block in response to a heave motion of a drilling vessel supporting the heave compensation system, coupling the cylinder assembly to a support structure via a cable, and using the cable to lower the cylinder assembly through an internal volume of a derrick of the drilling vessel to a rig floor of the drilling vessel.

Abstract: A bell design crown block for a top mounted compensator includes a removable, tilting sheave block mounted within the outside perimeter of a crown block yoke. An actuator installed in the crown block actuates the tilt function. No hinge adaptor is required and the sheave block does not hang past or below the crown block yoke. When used in a floating platform application, idler sheaves are mounted on the crown block yoke and an optional interface beam may be provided for the active heave cylinder head.