Stabilized hoist rig for deep ocean mining vessel

A structure for supporting a pipe string in pendulous suspension from the slip bowl of a hoist rig in a deep ocean mining vessel comprising, in combination:

• a first resilient bearing member disposed in load supporting relation intermediate the vessel and the hoist rig;
• a second resilient bearing member disposed in load supporting relation intermediate the hoist rig and the slip bowl;
• and,
• power means for angularly displacing the hoist rig with respect to the vessel to maintain vertical alignment of the hoist rig with the pipe string as the vessel rolls and pitches during pipe stabbing and removal operations performed during lowering and lifting of the pipe string.

In a seagoing vessel of the type including a well opening extending vertically through its deck and hull to permit lowering and lifting operations in the sea beneath the vessel, a platform disposed over the well opening for supporting a pipe string in pendulous suspension through the well opening, and a bearing member disposed intermediate of the platform and vessel and in load supporting engagement with the platform for permitting angular movement of the platform about its roll and pitch axes relative to the vessel, the combination of electromechanical control means operatively connected intermediate the platform and vessel for moving the platform angularly about its roll and pitch axes to maintain a predetermined angular displacement of the platform with respect to the axis of a pipe string supported by the platform as the vessel rolls and pitches, said electromechanical control means comprising:

• electromechanical transducer means for generating first and second electrical attitude signals proportional to the roll and pitch angular displacements, respectively, of the platform as measured with respect to a predetermined reference axis, the electromechanical transducer means including a vertical gyro mounted on the platform, the gyro having its vertical spin axis oriented in parallel with the local gravity field;
• electronic control circuit means for generating first and second position correction signals proportional to a predetermined function of the first and second attitude signals;
• respectively,
• first hydraulic actuator means having a first piston assembly operatively connected to angularly displace the platform about its roll axis relative to the vessel in response to the first position correction signal;
• and
• second hydraulic actuator means having a second piston assembly operatively connected to angularly displace the platform about its pitch axis relative to the vessel in response to the second position correction signal.

In a seagoing vessel of the type including a well opening extending vertically through its deck and hull to permit lowering and lifting operations in the sea beneath the vessel, a platform disposed over the well opening of supporting a pipe string in pendulous suspension through the well opening, and a bearing member disposed intermediate of the platform and vessel and in load supporting engagement with the platform for permitting angular movement of the platform about its roll and pitch axes relative to the vessel, the combination of electromechanical control means operatively connected intermediate the platform and vessel for moving the platform angularly about its roll and pitch axes to maintain a predetermined angular displacement of the platform with respect to the axis of a pipe string supported by the platform as the vessel rolls and pitches, said electromechanical control means comprising:

• electromechanical transducer means for generating first and second electrical attitude signals proportional to the roll and pitch angular displacements, respectively, of the platform as measured with respect to a predetermined reference axis, the electromechanical transducer means including first and second relative displacement roll and pitch transducer secured to the platform substantially along its roll axis and pitch axis, respectively, the transducers being oriented with respect to the platform to provide electrical signal outputs which are referenced to an arbitrary roll and pitch displacement of the platform with respect to the vessel, and further including a vertical gyro mounted on the vessel with its spin axis oriented in parallel with the local gravity field for providing roll and pitch output signals proportional to the roll and pitch angular displacement of the vessel relative to the local gravity field;
• electronic control circuit means for generating first and second position correction signals proportional to a predetermined function of the first and second attitude signals, respectively,
• first hydraulic actuator means having a first piston assembly operatively connected to angularly displace the platform about its roll axis relative to the vessel in response to the first position correction signal;
• and,
• second hydraulic actuator means having a second piston assembly operatively connected to angularly displace the platform about its pitch axis relative to the vessel in response to the second position correction signal.

In a seagoing vessel of the type including a well opening extending vertically through its deck and hull to permit lowering and lifting operations in the sea beneath the vessel, a platform disposed over the well opening for supporting a pipe string in pendulous suspension through the well opening, and a bearing member disposed intermediate of the platform and vessel and in load supporting engagement with the platform for permitting angular movement of the platform about its roll and pitch axes relative to the vessel, the combination of electromechanical control means operatively connected intermediate the platform and vessel for moving the platform angularly about its roll and pitch axes to maintain a predetermined angular displacement of the platform with respect to the axis of a pipe string supported by the platform as the vessel rolls and pitches, said electromechanical control means comprising:

• electromechanical transducer means for generating first and second electrical attitude signals proportional to the roll and pitch angular displacements, respectively, of the platform as measured with respect to a predetermined reference axis;
• electronic control circuit means for generating first and second position correction signals proportional to a predetermined function of the first and second attitude signals, respectively;
• bias means for generating artificial roll and pitch bias signals in response to manual control by an operator, the roll and pitch bias signals being selectively connected to the electronic control circuit means to permit manual control of the platform attitude by the operator,
• first hydraulic actuator means having a first piston assembly operatively connected to angularly displace the platform about its roll axis relative to the vessel in response to the first position correction signal;
• and
• second hydraulic actuator means having a second piston assembly operatively connected to angularly displace the platform about its pitch axis relative to the vessel in response to the second position correction signal.