In-line mooring connector and tensioner

1. An in-line [subsea] mooring chain tensioner comprising:

a chassis having a first, upper end and an opposing, second, lower end;

a connector on the second end of the chassis configured to engage an anchor line;

a first opening in the first end of the chassis sized and configured to permit the passage of a mooring chain;

a second opening in the chassis proximate the second end configured to direct a mooring chain exiting the chassis in a generally downward direction, off-axis the chassis;

a first chain stopper within the chassis moveable from a first position that engages a mooring chain passing from the first opening through the second opening to a second position that permits movement of the chain through the chassis;

a chain jack removably mounted within the chassis and comprising

a base plate having a generally U-shaped central opening;

a pair of hydraulic cylinders attached to the base plate with one cylinder on either side of the central opening and a hydraulic actuator extending from each cylinder;

a moveable plate having a U-shaped central opening connected to the hydraulic actuators and parallel to the base plate;

a second chain stopper mounted on the moveable plate and moveable from a first position that engages a mooring chain passing through the U-shaped central opening to a second position that permits movement of the chain through the central opening.

2. The in-line mooring chain tensioner recited in claim 1 wherein the chassis is open on at least one side so as to permit removal of the chain jack.

3. The in-line mooring chain tensioner recited in claim 1 wherein the first and second chain stoppers are hydraulically actuated.

4. The in-line mooring chain tensioner recited in claim 3 wherein the first and second chain stoppers are configured for hydraulic actuation by a subsea remotely operated vehicle.

5. The in-line mooring chain tensioner recited in claim 3 wherein the first and second chain stoppers are configured for hydraulic actuation via an umbilical line from a surface vessel.

6. The in-line mooring chain tensioner recited in claim 1 wherein the hydraulic cylinders of the chain tensioner are configured for hydraulic actuation by a subsea, remotely operated vehicle.

7. The in-line mooring chain tensioner recited in claim 1 wherein the hydraulic cylinders of the chain tensioner are configured for hydraulic actuation via an umbilical line from a surface vessel.

8. The in-line mooring chain tensioner recited in claim 1 further comprising a chain cruciform proximate the first opening in the first end of the chassis.

9. The in-line mooring chain tensioner recited in claim 1 further comprising a chain cruciform proximate the second opening in the chassis.

10. The in-line mooring chain tensioner recited in claim 1 further comprising a sensor responsive to the tension load on the chassis.

11. The in-line mooring chain tensioner recited in claim 1 further comprising a sensor responsive to the position of the hydraulic actuators.

12. The in-line mooring chain tensioner recited in claim 1 further comprising a first sensor responsive to the position of the first chain stopper and a second sensor responsive to the position of the second chain stopper.

13. The in-line mooring chain tensioner recited in claim 1 further comprising a housing within the chassis surrounding the first chain stopper on at least two sides.

14. The in-line mooring chain tensioner recited in claim 13 wherein the base plate of the removable chain jack bears against the housing when the chain jack moves a chain passing through the in-line chain tensioner.

15. The in-line mooring chain tensioner recited in claim 14 wherein the hydraulic cylinders of the chain jack surround the housing on at least two sides thereof.

16. The in-line mooring chain tensioner recited in claim 1 further comprising a gate configured to close the U-shaped opening in the base plate around a chain passing through the chain tensioner.

17. The in-line mooring chain tensioner recited in claim 1 further comprising a gate configured to close the U-shaped opening in the moveable plate around a chain passing through the chain tensioner.

18. An in-line [subsea] mooring chain tensioner comprising:

a chassis having a first, upper end and an opposing, second, lower end;

a connector on the second end of the chassis configured to engage an anchor line;

a first opening in the first end of the chassis sized and configured to permit the passage of a mooring chain;

a second opening in the chassis proximate the second end configured to direct a mooring chain exiting the chassis in a generally downward direction, off-axis the chassis;

a first chain stopper within the chassis moveable from a first position that engages a mooring chain passing from the first opening through the second opening to a second position that permits movement of the chain through the chassis;

a chain jack removably mounted within the chassis and comprising

a base plate having a generally U-shaped central opening;

a second chain stopper mounted on the base plate and moveable from a first position that engages a mooring chain passing through the U-shaped central opening to a second position that permits movement of the chain through the central opening,

a pair of hydraulic cylinders attached to the base plate with one cylinder on either side of the central opening and a hydraulic actuator extending from each cylinder;

a moveable plate having a U-shaped central opening connected to the hydraulic actuators and parallel to the base plate;

a third chain stopper mounted on the moveable plate and moveable from a first position that engages a mooring chain passing through the U-shaped central opening to a second position that permits movement of the chain through the central opening.

19. The in-line mooring chain tensioner recited in claim 18 wherein the first chain stopper is configured for mechanical actuation by a remotely operated vehicle and both the second chain stopper and the third chain stopper are hydraulically actuated.

20. An in-line [subsea] mooring chain tensioner comprising:

a chassis having a first, upper end and an opposing, second, lower end;

a first connector on the first end of the chassis having means for engaging a removable chain jack;

a second connector on the second end of the chassis configured to engage an anchor line;

a first opening in the first end of the chassis sized and configured to permit the passage of a mooring chain;

a second opening in the chassis proximate the second end configured to direct a mooring chain exiting the chassis in a generally downward direction, off-axis the chassis;

a first chain stopper within the chassis moveable from a first position that engages a mooring chain passing from the first opening through the second opening to a second position that permits movement of the chain through the chassis;

a chain jack removably engaged to the first connector on the first end of the chassis and comprising

a base plate having a generally U-shaped central opening;

a pair of hydraulic cylinders attached to the base plate with one cylinder on either side of the central opening and a hydraulic actuator extending from each cylinder;

a moveable plate having a U-shaped central opening connected to the hydraulic actuators and parallel to the base plate;

a second chain stopper mounted on the moveable plate and moveable from a first position that engages a mooring chain passing through the U-shaped central opening to a second position that permits movement of the chain through the central opening.

21. A method for tensioning a subsea anchor line comprising:

providing a mooring connector in an anchor line between a first lower portion and a second upper portion comprised of chain, said mooring connecter having means for attaching a removable chain jack;

attaching a removable chain jack to the mooring connector from a surface vessel while the anchor line is under tension;

moving the upper portion of the anchor line relative to the lower portion of the anchor line and the mooring connector by actuating the chain jack;

locking the upper portion of the anchor line to the mooring connector;

detaching the removable chain jack from the mooring connector; and,

recovering the removable chain jack at the surface vessel.