Twin hull semi-submersible derrick barge

Abstract

The derrick barge comprises a pair of laterally spaced elongated hulls having a plurality of upstanding columns spaced therealong supporting a working platform and a heavy duty derrick or crane in spaced relation above the hulls. The hulls buoyantly support the vessel including its deck load in the floating condition with the hulls having freeboard. The hulls have ballast compartments to submerge the hulls and portions of the stabilizing columns to a distance of approximately one-half the effective height of the stabilizing columns to maintain the vessel in a semisubmerged floating condition with the platform and derrick elevated above the waterline. However, the vessel also may be ballasted or deballasted to submerge or emerge to a greater or lesser extent from the semisubmerged condition such that the distance between the mean water surface and either the underside of the deck or top side of the hull is not less than 0.75 of the mean wave height. The columns stabilize the vessel in the semisubmerged condition about roll and pitch axes. The heavy duty derrick is located adjacent the stern portion of the vessel with its vertical axis of rotation intersecting the vessel centerline. This novel twin hull column stabilized derrick barge arrangement has excellent motion minimizing characteristics under wave action in operations at sea.

Description

Claims

1. A column stabilized semisubmersible barge for marine construction, pipelaying and like other offshore operations, said barge consisting of a pair of elongated hulls disposed in substantially parallel spaced side-by-side relation with each of said hulls spaced from and lying on an opposite side of the longitudinal centerline of said barge, and said barge further comprising:

a working platform spaced above said hulls a predetermined height and normally lying in a generally horizontal plane;

means for supporting said platform in fixed spaced relation above said hulls including at least three pairs of upstanding columns connecting with each of said hulls and said platform; each of said columns having a substantially constant cross sectional area over the effective height of the column between the platform and associated hull;

each of said hulls having, over substantially the entire length thereof, a substantially rectangular transverse cross section with its breadth greater than its height;

a plurality of longitudinally spaced structural truss means interconnecting and reinforcing the structural relationship of the hulls, platform and columns, with such truss means including substantially transversely extending members structurally interconnecting uppermost portions of the hulls;

said barge being generally rectangular in plan with the length of said barge along its longitudinal centerline and roll axis being at least about 2.0 times greater than the width of said barge along its transverse centerline and pitch axis;

at least three of said columns being located on each of said two hulls on opposite sides of the barge's roll axis with pairs of such columns being located near opposite ends of each of said hulls on opposite sides of the barge's pitch axis and another pair of said columns being located at an intermediate position on each of said hulls;

each of said columns having an oblong cross section with a dimension extending in the direction of the barge's longitudinal axis greater than the column's dimension extending transversely of this barge axis;

the centroid of the cross section of each column on said hulls lying outboard of the longitudinal centerline of the associated hull;

the configuration and cross-sectional areas of said columns throughout effective height thereof and the distances of said columns from the barge's longitudinal roll axis and transverse pitch axis being such that said columns provide sufficient righting moments about roll and pitch axis when the barge is in high draft semisubmerged operating positions and also being such that said columns providing righting moment about the transverse pitch axis which is greater than righting moment provided about the longitudinal roll axis when the barge is in semisubmerged column stabilized operating positions;

said hulls having ballast compartments;

means for ballasting said barge when required to alter its draft between a low draft hull-supported floating condition in which the hulls have freeboard with said transversely extending members structurally interconnecting uppermost portions of the hulls being disposed above the mean waterline and a high draft semisubmerged column stabilized floating and operating condition in which the mean waterline is located along intermediate portions of said columns above said hulls and below the underside of said platform;

crane means mounted on said barge for transferring loads between spaced positions on said platform, said crane means being of sufficient size and capacity for various marine construction, pipelaying and other like offshore operations;

said means for ballasting including means for adjusting vessel angle of heel change caused during semisubmerged barge and crane means operations to provide a reduction of the barge's angle of heel about its roll axis when required during semisubmerged column stabilized barge and crane means operations; and

said means for ballasting including means for adjusting vessel angle of trim change caused during semisubmerged barge and crane means operations to provide a reduction of the vessel's angle of trim about its pitch axis when required during semisubmerged column stabilized barge and crane means operations.

2. A barge according to claim 1 wherein said height of the barge platform above said hulls and the effective height of said columns is at least 20 feet.

3. A barge according to claim 1 wherein said crane means includes a rotatable crane having a lifting boom, with said rotatable crane positioned inboard of the center of the columns on the hulls.

4. A barge with means according to claim 1 wherein said crane means includes a rotatable crane having a lifting boom, with the rotatable crane's center of gravity positioned inboard of the centroids of said columns located on said hulls.

5. A barge according to claim 1, wherein each of said rectangular twin hulls includes at least two separate ballast compartments spaced transversely within each hull and a plurality of separate ballast compartments spaced longitudinally within each hull.

6. A barge according to claim 1, wherein said vessel ballast means includes means for transferring ballast from one of said rectangular twin hulls directly to the other of said rectangular twin hulls for controlling heel of said barge about its roll axis when required during semisubmerged column stabilized barge and crane means operations.

7. A barge according to claim 1, wherein: each of said rectangular twin hulls includes at least two separate ballast compartments spaced transversely within each hull and a plurality of separate ballast compartments spaced longitudinally with each hull; and said barge ballast means also includes means for transferring ballast from at least one compartment in one hull directly to at least one compartment in the other hull for controlling the heel of said barge about its roll axis when required during semisubmerged column stabilized barge and crane means operations.

8. A barge according to claim 1, wherein the outboard sides of said oblong columns are substantially in vertical alignment with the outboard sides of the associated rectangular twin hulls.

9. A barge according to claim 1, wherein said crane means inclues a rotatable crane having a lifting boom suitable for transferring loads between positions longitudinally spaced along said platform for various marine construction, pipelaying and other like offshore operations, with said rotatable crane's center of gravity positioned inboard of the centroids of said columns on said twin hulls; and said barge ballasting means includes conduits, pumps and valves for ballasting each hull and for ballasting between said hulls to control the barge's attitude of heel when required about the roll axis and the barge's attitude of trim when required about the pitch axis in correlation to position of said crane means and operation thereof with a load.

10. A barge according to claim 1, wherein said crane means includes a rotatable derrick mounted near one end of the barge.

11. A vessel according to claim 10, wherein said rotatable derrick has an axis of rotation lying in a vertical plane containing the roll axis of the barge.

12. A column stabilized semisubmersible barge for marine construction, pipelaying and like other offshore operations, said barge consisting of a pair of elongated hulls disposed in substantially parallel spaced side-by-side relation with each of said hulls spaced from and lying on an opposite side of the longitudinal centerline of said barge, and said barge further comprising:

a working platform spaced above said hulls a predetermined height and normally lying in a generally horizontal plane;

means for supporting said platform in fixed spaced relation above said hulls including at least three pairs of upstanding columns connecting with each of said hulls and said platform; each of said columns having a substantially constant cross sectional area over the effective height of the column between the platform and associated hull;

each of said hulls having an oblong transverse cross section with a breadth greater than its height and having top and bottom substantially planar parallel surfaces extending substantially the entire length of each hull, whereby such hulls configuration provides increased mass resistance to movement of said hulls and vessel through water in a vertical direction when the vessel is in high draft semisubmerged column stabilized operating condition;

a plurality of longitudinally spaced structural truss means interconnecting and reinforcing the structural relationship of the hulls, platform and columns, with such truss means including substantially transversely extending members structurally interconnecting uppermost portions of the hulls;

said barge being generally rectangular in plan with the length of said barge along its longitudinal centerline and roll axis being at least plural times as great as the width of said vessel along its transverse centerline and pitch axis;

at least three of said columns being located on each of said two hulls on opposite sides of the barge's roll axis with pairs of such columns being located near opposite ends of each of said hulls on opposite sides of the barge's pitch axis and another pair of said columns being located at an intermediate position on each of said hulls;

at least one of said columns on each said hull having an oblong cross section with a dimension extending in the direction of the longitudinal vessel axis greater than the column's transversely extending dimension; the centroid of the cross section of such oblong columns lying outboard of the longitudinal centerline of each associated hull;

the configuration and cross-sectional areas of said columns throughout effective height thereof and the distances of said columns from the barge's longitudinal roll axis and transverse pitch axis being such that said columns provide sufficient righting moments about roll and pitch axes when the barge is in high draft semisubmerged operating positions and also being such that said columns provide righting moment about the transverse pitch axis which is greater than righting moment provided about said longitudinal roll axis when the barge is in semisubmerged column stabilized operation position;

said hulls having ballast compartments;

means for ballasting said barge when required to alter its draft between a low draft hull-supported floating condition in which the hulls have freeboard with said transversely extending members structurally interconnecting uppermost portions of the hulls being disposed above the mean waterline and a high draft semisubmerged column stabilized floating and operating condition in which the mean waterline is located along intermediate portion of said columns above said hulls and below the underside of said platform;

each of said oblong twin hulls including at least two separate ballast compartments spaced transversely within each hull and a plurality of separate ballast compartments spaced longitudinally within each hull;

crane means mounted on said barge for transferring loads between spaced positions on said platform, said crane means being of sufficient size and capacity for various marine construction, pipelaying and other like offshore operations;

said means for ballasting including means for adjusting barge angle of heel change caused during semisubmerged barge and crane means operations to provide a reduction of the vessel's angle of heel about its roll axis when required during semisubmerged column stabilized barge and crane means operations;

said means for ballasting including means for adjusting barge angle of trim change caused during semisubmerged barge and crane means operations to provide a reduction of the vessel's angle of trim about its pitch axis when required during semisubmerged column stabilized barge and crane means operations.

13. A barge according to claim 12 wherein the height of the barge platform above said hulls and the effective height of said columns is at least 20 feet.

14. A barge according to claim 12 wherein said crane means includes a rotatable crane having a lifting boom, with said rotatable crane positioned inboard of the center of the columns on the hulls.

15. A barge with crane means according to claim 12 wherein said crane means includes a rotatable crane having a lifting boom, with the rotatable crane's center of gravity positioned inboard of the centroids of said columns located on said hulls.

16. A barge according to claim 12 wherein said barge ballast means includes means for transferring ballast directly from one hull to the other hull to control heel of said barge about its roll axis during semisubmerged column stabilized barge and crane means operations.

17. A vessel according to claim 12 wherein the centroid of all of said columns lies outboard of the longitudinal centerline of each associated hull.

18. A barge according to claim 17 wherein all of said columns have such an oblong cross section with greater dimension extending in direction of the barge's longitudinal axis.

19. A barge according to claim 18 wherein the outboard sides of said oblong columns are substantially in vertical alignment with the outboard sides of the associated twin hulls.

20. A vessel according to claim 12 wherein each of said hulls is generally rectangular in cross section.

21. A vessel according to claim 12 wherein the length of said barge compared to width of said barge is at least about 2.0 to 1.

22. A vessel according to claim 12 wherein said vessel has a length which is at least about 2.0 times as great as its width; each of said columns has an oblong cross section with a dimension extending in the direction of the longitudinal vessel axis greater than the column's dimension extending transversely of the vessel; the centroid of the cross section of each column on each hull lies outboard of the longitudinal centerline of the associated hull; each of said hulls is generally rectangular in cross section; and said transversely extending members structurally interconnect said hulls at the uppermost portions thereof.

23. A vessel according to claim 22 wherein said barge ballasting means includes means operable to transfer ballast from at least one compartment in one hull directly to at least one compartment in the other hull to control the heel of said barge about its roll axis when required during column stabilized semisubmerged barge and crane operations.

24. A barge according to claim 12, wherein said crane means includes a rotatable crane having a lifting boom suitable for transferring loads between positions longitudinally spaced along said platform for various marine construction, pipelaying and other like offshore operations, with said rotatable crane's center of gravity positioned inboard of the centroids of said columns on said twin hulls; and said barge ballasting means including conduits, pumps and valves for ballasting each hull and for ballasting between said hulls to control the barge's attitude of heel when required about the roll axis and the barge's attitude of trim when required about the pitch axis in correlation to position of said crane means and operation thereof with a load.

25. A barge according to claim 12 wherein said crane means includes a rotatable derrick mounted near one end of the barge.

26. A vessel according to claim 25 wherein said rotatable derrick has an axis of rotation lying in a vertical plane containing the roll axis of the barge.

27. A column stabilized semisubmersible barge for marine construction, pipelaying and like other offshore operations, said barge consisting of a pair of elongated hulls disposed in substantially parallel spaced side-by-side relation with each of said hulls spaced from and lying on an opposite side of the longitudinal centerline of said barge, and said barge further comprising:

a working platform spaced above said hulls a predetermined height and lying in a generally horizontal plane;

means for supporting said platform in fixed spaced relation above said hulls including at least three pairs of upstanding columns connecting with each of said hulls and said platform;

each of said columns having a substantially constant cross sectional area over the effective height of the column between the platform and associated hull;

each of said hulls having an oblong transverse cross section with a breadth greater than its height and having top and bottom substantially planar parallel surfaces extending substantially the entire length of each hull;

a plurality of longitudinally spaced structural truss means interconnecting and reinforcing the structural relationship of the hulls, platform and columns with such truss means including substantially transversely extending members structurally interconnecting uppermost portions of the hulls;

said barge being generally rectangular in plan with the length of said barge along its longitudinal centerline and roll axis being substantially greater than the width of said barge along its transverse centerline and pitch axis;

at least three of said columns being located on each of said two hulls on opposite sides of the barge's roll axis with pairs of such columns being located near opposite ends of each of said hulls on opposite sides of the barge's pitch axis and another pair of said columns being located at an intermediate position on each of said hulls;

the configuration and cross-sectional areas of said columns throughout effective height thereof and the distances of said columns from the barge's longitudinal roll axis and transverse pitch axis being such that said columns provide sufficient stabilizing righting moments about roll and pitch axes when the barge is in high draft semisubmerged operating positions and also being such that said columns provide righting moment about the longitudinal roll axis which is less than righting moment provided about said transverse pitch axis when the vessel is in semisubmerged column stabilized operating position;

said hulls having ballast compartments;

means for ballasting said barge when required to alter its draft between a low draft hull-supported floating condition and a high draft semisubmerged column stabilized floating and operating condition in which the mean waterline is located along intermediate portion of said columns above said hulls and below the underside of said platform; crane means mounted on said barge for transferring loads between spaced positions on said platform, said crane means being of sufficient size and capacity for various marine construction, pipelaying and other like offshore operations;

said means for ballasting including means for adjusting vessel angle of heel change caused during semisubmerged barge and crane means operations to provide a reduction of the barge's angle of heel about its roll axis when required during semisubmerged column stabilized barge and crane means operations; and

said means for ballasting including means for adjusting vessel angle of trim change caused during semisubmerged barge and crane means operations to provide a reduction of the vessel's angle of trim about its pitch axis when required during semisubmerged column stabilized barge and crane means operatons.

28. A barge according to claim 27 wherein the height of the barge platform above said hulls and the effective height of said columns is at least 20 feet.

29. A barge according to claim 27 wherein said crane means includes a rotatable crane having a lifting boom, with said rotatable crane positioned inboard of the center of the columns on the hulls.

30. A barge with means according to claim 27 wherein said crane means includes a rotatable crane havng a lifting boom, with the rotatable crane's center of gravity positioned inboard of the centroids of said columns located on said hulls.

31. A barge acording to claim 27 wherein said crane means includes a rotatable crane having a lifting boom suitable for transferring loads between positions longitudinally spaced along said platform for various marine construction, pipelaying and other like offshore operations, with said rotatable crane's center of gravity positioned inboard of the centroids of said columns on said twin hulls; and said barge ballasting means includes conduits, pumps and valves for ballasting each hull and for ballasting between said hulls to control the barge's attitude of heel when required about the roll axis and the barge's attitude of trim when required about the pitch axis in correlation to position of said crane means and operation thereof with a load.

32. A barge according to claim 31, wherein: each of said hulls is generally rectangular in cross section and said barge has a length which is at least plural times as great as its width; the centroid of the cross section of each column on each hull lies outboard of the longitudinal centerline of the associated hull; and each of said columns has an oblong cross section with a dimension extending in the direction of the longitudinal barge axis greater than the column's dimension extending transversely of the barge.

33. A barge according to claim 27, wherein each of said hulls includes at least two separate ballast compartments spaced transversely within each hull and a plurality of separate ballast compartments spaced longitudinally within each hull.

34. A barge according to claim 27, wherein said barge ballast means includes means for transferring ballast directly from one hull to the other hull to control heel of said barge about its roll axis when required during semisubmerged column stabilized operations.

35. A barge according to claim 27, wherein the centroid of the cross section of at least one column on each hull lies outboard of the longitudinal centerline of the associated hull.

36. A barge according to claim 35 wherein at least one of the columns on each said hull has an oblong cross section with a dimension extending in the direction of the longitudinal barge axis greater than the column's transversely extending dimension.

37. A barge according to claim 27, wherein the centroid of all of said column lies outboard of the longitudinal centerline of the associated hull.

38. A barge according to claim 37 wherein all of said columns have such as oblong cross section with greater dimension extending in direction of the barge's longitudinal axis.

39. A barge according to claim 38 wherein the outboard sides of said oblong columns are substantially in vertical alignment with the outboard sides of the associated hull.

40. A barge according to claim 27, wherein each of said hulls is generally rectangular in cross section.

41. A barge according to claim 27, wherein said vessel has a length to width ratio of at least about 2.0 to 1.

42. A barge according to claim 27, wherein at least the upper end of said columns is modified in cross section to provide mechanical connection between the columns and the platform.

43. A barge according to claim 42, wherein said modified column cross section includes a frustoconical section.

44. A barge according to claim 43 wherein at least the lower end of said columns is modified in cross section to provide mechanical connection between the columns and the associated hulls.

45. A barge according to claim 44 wherein said modified column cross section includes a frustoconical section.

46. A barge as in claim 27 wherein the centroids of the water plane areas defined by the cross sections of the columns are located outboard of the centerlines of the hulls an extended distance from the centerline of the barge on opposite sides of the longitudinally extending roll axis to develop larger moments of inertia of the water plane area about the roll axis (than would otherwise be the case if the longitudinal centerlines of said hulls and their associated columns were coincident).

47. A barge as in claim 27 wherein: said trusses include transversely extending members connecting one hull to the other at the uppermost portions of said hulls.

48. A barge as in claim 27 wherein the barge has six columns including three columns on each hull, with one middle pair of columns located adjacent the barge's transverse pithc axis and with two other pairs of columns on opposite sides of the barge pitch axis in generally symmetrical relation thereto near opposite ends of the associated hulls.

49. A barge as in claim 27 wherein: the barge has a total odd number of pairs of columns and the middle pair of columns is located adjacent the barge's pitch axis, with the remaining pairs of columns being disposed in equal numbers on opposite sides of the axis and with two pairs of columns located near opposite ends of said hulls.

50. A barge as in claim 27, wherein: the barge has a total even number of pairs of columns and the middle two pairs of columns are located on opposite sides of and near the transverse pitch axis; the remaining pairs of said columns being located outwardly of said middle pairs of columns and including two pairs of end columns on the hull near opposite ends of said hulls.

51. A barge according to claim 27, wherein said crane means includes a rotatable derrick mounted near one end of the barge.

52. A vessel according to claim 27, wherein said rotatable derrick has an axis of rotation lying in a vertical plane containing the roll axis of the barge.

53. A barge as claimed in claim 27, including means for anchoring the barge in the high draft semisubmerged column stabilized barge and crane means operating positions, said means including mooring winches located near opposite ends of the barge.