Offshore ship-to-ship lifting with target tracking assistance

1. A method for a first vessel having a crane thereon and a second vessel, the method comprising:

tracking an optical target mounted on the second vessel with a target tracking device positioned on the first vessel, wherein the target tracking device comprises a base mounted at a first position offset at a distance from a boom of the crane, a rotating mount mounted on the base and rotatable relative to the base, and an optical viewer mounted to the rotating mount and configured to recognize the optical target, wherein the base of the target tracking device is fixed at the first position connected to a deck of the first vessel during rotational movement of the crane such that movement of the optical viewer is independent of the rotational movement of the crane, and the optical target is mounted at a second position offset at a distance from an object to be lifted or landed;

producing data using the target tracking device in response to the tracking of the optical target;

determining a relative motion between the first vessel and the second vessel based on the data produced using the target tracking device;

determining one or more of a lifting capacity of the crane or an available hook height of a hook of the crane at a designated location, based on the relative motion, prior to moving the boom toward the designated location; and

lifting or landing the object from or to the designated location.

2. The method of claim 1 , wherein the data produced using the target tracking device indicates a distance between the target tracking device and the optical target.

3. The method of claim 2 , wherein the data produced using the target tracking device indicates a relative angle between an axis and a line of sight from the target tracking device to the optical target, and the method further comprises displaying information on a display, the information indicating the relative motion between the first vessel and the second vessel, wherein the display is a heads-up display.

4. The method of claim 1 , wherein the designated location indicates the object on the first vessel to be lifted.

5. The method of claim 1 , wherein the designated location indicates a landing location on the second vessel for the object.

6. The method of claim 1 , further comprising selecting a second target that defines a travel path of the hook of the crane.

7. The method of claim 6 , further comprising displaying the travel path on a heads-up display.

8. The method of claim 3 , further comprising:

determining a horizontal distance between a base of the crane and the designated location based on the data produced using the target tracking device; and

displaying on the heads-up display one or more of the available hook height or the lifting capacity of the crane at the designated location prior to moving the boom toward the designated location, the designated location being adjacent the optical target located on the second vessel.

9. The method of claim 1 , further comprising compensating for the relative motion between the first vessel and the second vessel in response to the data produced using the target tracking device.

10. The method of claim 1 , wherein the object is an end of a ship-to-ship walkway.

11. The method of claim 1 , wherein the rotating mount is rotatable about a first axis, the optical viewer is rotatable relative to the rotating mount and is rotatable about a second axis that extends perpendicularly to the first axis, and the optical target is mounted at the second position offset at a distance from a deck of the second vessel.

12. A method for a first vessel having a crane thereon and a second vessel, the method comprising:

tracking an optical target mounted on the second vessel with a target tracking device positioned on the first vessel, wherein the target tracking device comprises a base mounted at a first position offset at a distance from a boom of the crane, a rotating mount mounted on the base and rotatable relative to the base, and an optical viewer mounted to the rotating mount and configured to recognize the optical target, wherein the base of the target tracking device is fixed at the first position connected to a deck of the first vessel during rotational movement of the crane such that movement of the optical viewer is independent of the rotational movement of the crane, and the optical target is mounted at a second position offset at a distance from an object to be lifted or landed;

in response to the tracking, producing data using the target tracking device that indicates:

a distance between the target tracking device and the optical target; and

a relative angle between an axis and a line of sight from the target tracking device to the optical target;

determining a relative motion between the first vessel and the second vessel based on the data produced using the target tracking device; and

determining one or more of a lifting capacity of the crane or an available hook height of a hook of the crane at a designated location, based on the relative motion, prior to moving the boom toward the designated location; and

lifting or landing the object from or to the designated location.

13. The method of claim 12 , further comprising displaying information on a display, the information indicating the relative motion between the first vessel and the second vessel.

14. The method of claim 13 , wherein the display is a heads-up display.

15. The method of claim 14 , further comprising selecting a second target that defines a travel path of the hook of the crane.

16. The method of claim 15 , further comprising displaying the travel path on the heads-up display.

17. The method of claim 14 , further comprising:

determining a horizontal distance between a base of the crane and the designated location based on the data produced using the target tracking device; and

displaying on the heads-up display one or more of the available hook height or the lifting capacity of the crane at the designated location prior to moving the boom toward the designated location, the designated location being adjacent the optical target located on the second vessel.

18. The method of claim 12 , further comprising:

compensating for the relative motion between the first vessel and the second vessel in response to the data produced using the target tracking device; and

performing the compensating while performing the lifting or the landing of the object.

19. The method of claim 12 , wherein the optical target is an optical grid.

20. A system, comprising:

a crane;

a controller coupled to the crane;

an optical grid; and

a camera, wherein the camera comprises a base mounted at a first position offset at a distance from a boom of the crane, a rotating mount mounted on the base and rotatable relative to the base, and an optical viewer mounted to the rotating mount and configured to recognize the optical grid, wherein the base of the camera is fixed at the first position connected to a deck of a first vessel during rotational movement of the crane such that movement of the optical viewer is independent of the rotational movement of the crane, and the optical grid is mounted at a second position offset at a distance from an object to be lifted or landed, wherein the camera is configured to track the optical grid and produce data in response to the tracking of the optical grid, the controller is configured to receive the data from the camera, and in response to receiving the data:

determine a relative motion between the optical grid and the camera based on the data produced using the camera, and

determine one or more of a lifting capacity of the crane or an available hook height of a hook of the crane at a designated location, based on the relative motion, prior to moving the boom toward the designated location.

21. The system of claim 20 , wherein the optical grid comprises a plurality of alternating shapes that are recognizable and distinguishable by the camera, the rotating mount is rotatable about a first axis, the optical viewer is rotatable relative to the rotating mount and is rotatable about a second axis that extends perpendicularly to the first axis, and the optical grid is mounted at the second position offset at a distance from a deck of a second vessel.