Method of constructing a twin hulled, column stabilized, semi-submersible derrick barge

• US 4,165,702 A
• Filed: 02/04/1977
• Issued: 08/28/1979
• Est. Priority Date: 07/08/1974
• Status: Expired due to Term

• Current Assignee: Santa Fe International Corp.
• Original Assignee: Santa Fe International Corp.
• Inventors: Goren, Yoram, Lloyd, Samuel H. III
• Primary Examiner(s): Frankfort, Charles E.
• Application Number:
  US05/765,583
• Time in Patent Office: 935 Days
• Field of Search: 114/51, 114/65 R, 114/61, 114/77 R, 114/77 A, 114/258, 114/259, 114/261, 114/264, 114/265, 212/3 R, 61/86, 61/87, 61/98, 405/195, 405/196, 405/205
• US Class Current: 114/65.00R
• CPC Class Codes: B63B 1/107 Semi-submersibles; Small waterline area multiple hull vessels and the like, e.g. SWATH
• CPC Class Codes: B63B 35/44 Floating buildings, stores, drilling platforms, or workshops, e.g. carrying water-oil separating devices construction methods for floating offshore platforms B63B75/00
• CPC Class Codes: B63B 39/03 by transferring liquids
• CPC Class Codes: B66C 23/52 Floating cranes floating dredgers E02F

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 bouyantly 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.

Claims

1. A method of constructing a column stabilized semisubmersible derrick barge comprising the steps of fabricating a pair of elongated hulls, disposing said hulls 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, fabricating a working platform, locating a plurality of columns between each of said hulls and said platform, connecting opposite end portions of said columns to said platform and said hulls, respectively, for supporting said platform in fixed spaced relation above said hulls at least in part by said columns, forming said barge such that the distance between the extremities of the barge along its longitudinal centerline is substantially greater than the distance between the extremities of the barge along its transverse centerline, providing at one end of said barge a mounting means for a heavy duty crane of a size having a rated capacity and a rotatable boom of sufficient length capable of performing lifting operations off both barge beams and off the end of said barge adjacent to the mounting means, providing ballast compartments in said hulls of a capacity to ballast said barge when in use to alter its draft between a low draft hull supported floating condition and a high draft semi-submerged column stabilized floating condition, forming said hulls to provide a combined displacement sufficient to float the barge when in use in said low draft condition with the hulls having freeboard, locating at least three of the aforementioned columns connected with each of the hulls on opposite sides of the roll axis of the barge, locating one such column near each of the opposite ends of each hull on opposite sides of the pitch axis of the barge, locating another of such columns at an intermediate position on each hull, and providing such columns configurations and areas and locating such columns at distances from the longitudinal roll axis and transverse pitch axis of said barge when in use to provide a significantly greater righting moment about the transverse pitch axis of the barge than the righting moment about the longitudinal roll axis thereof when said barge is in use in the high draft condition, and to maintain a barge attitude keeping the axis of rotation of the crane within a predetermined crane slew limiting angle for predetermined magnitudes of load and boom outreach and beyond which angle the crane cannot slew, and providing a plurality of longitudinally spaced structural means reinforcing the structural relationship of said hulls, platform and columns including providing substantially transversely extending members interconnecting the hulls adjacent uppermost portions thereof for restraining the hulls against relative lateral displacement when the barge is in use.

2. The method according to claim 1 including providing said crane on said barge at one end thereof.

3. The method according to claim 2 including locating at least one column on each hull adjacent the end of said barge at substantially the same longitudinal position at which said crane is mounted and at a distance from the transverse centerline of said barge at least substantially the same as the distance between said transverse centerline and the crane'"'"'s axis of rotation.

4. The method according to claim 2 including providing structural support means including support members directly connecting between the base of said crane and each of said pair of hulls for at least partially structurally supporting said crane from said hulls.

5. The method according to claim 2 including providing a boom of such length that its end reaches adjacent the end of said barge opposite the end at which said crane is mounted when said boom is disposed in the rest position.

6. A method according to claim 2 including providing said crane with an axis of rotation lying in a vertical plane located substantially along the longitudinal roll axis of the barge.

7. The method according to claim 1 wherein:

the anticipated crane load capacity and boom outreach length are such that when the crane is rotated in use in high draft condition of the barge with load and outreach of predetermined values the resultant moment with respect to the roll axis causes substantial heel of said barge about said axis which if uncorrected would exceed the maximum slew limiting angle of said crane and including providing ballast means for counteracting such angle of heel caused by such crane operations to provide a counter-righting moment for said barge about its roll axis sufficient to maintain the angle of heel of the barge during crane operations within said slew limiting angle of said crane.

8. The method according to claim 7 including providing ballast means operable to transfer ballast from one hull to the other hull in a manner to achieve such counterrighting moment to maintain the heel of said barge when in use within the crane slew limiting angle, with said ballast being transfereable as the crane slews during load operating conditions.

9. The method according to claim 7 including providing ballast means operable to transfer ballast between said hulls in relation to the moment caused by operation of the crane to provide sufficient counter-righting moment to maintain the heel of said barge within the predetermined crane slew limiting angle.

10. The method according to claim 7 including providing ballast means for counteracting the angle of trim caused when said crane boom extends outwardly away from the end of said barge in the direction of the barge'"'"'s longitudinal axis with load and boom outreach of high magnitude causing a high resultant moment with respect to the pitch axis of said barge so that the latter mentioned ballast means may provide a countermoment for reducing the angle of trim of the barge about its pitch axis.

11. The method according to claim 1 including forming one of said columns on each of said hulls of a cross section whereby the column dimension extending in the direction of the barge roll axis is greater than the transverse dimension of the column.

12. The method according to claim 1 including forming said barge so that it has a length-to-width ratio such that the barge length is at least a plural number of times as great as the barge width.

13. The method according to claim 1 including forming the upper and lower surfaces of each of said hulls to provide a non-streamlined configuration and increase added mass when the barge is in use thereby to increase resistance to movement of said hulls through water in a vertical direction when said barge is in said high draft column stabilized semi-submerged condition.

14. A method according to claim 1 including providing said columns with an effective height of at least twenty-three feet between said hulls and said working platform.

15. A method according to claim 14 including providing said columns with a substantially constant cross section throughout the effective height thereof.

16. A method according to claim 1 including providing a plurality of longitudinally spaced truss means interconnecting said working platform and hulls as part of said longitudinally spaced structural means reinforcing the structural relationship of said hulls, platform and columns.

17. A method of constructing a column stabilized semisubmersible barge for offshore construction, pipelaying and like uses comprising the steps of:

fabricating a pair of elongated hulls of oblong cross section and disposing said hulls in substantially parallel spaced side-by-side relation with end of said hulls spaced from and lying on an opposite side of the longitudinal centerline and roll axis of the barge;

fabricating and disposing at least three columns extending upwardly from each of said hulls;

fabricating a working platform;

connecting opposite end portions of said columns to said working platform and to said hulls respectively for supporting said working platform in fixed spaced relation above said hulls at least in part by said columns, and forming said barge so that the distance between the extremities of the barge along its longitudinal centerline is substantially greater than the distance between the extremities of the barge along its transverse centerline with the barge working platform having sides extending in the direction of its roll axis and ends extending substantially transversely thereto, and locating one such column near each of the opposite ends of each hull on opposite sides of the pitch axis of the barge while locating at least another of such columns at an intermediate position on each hull;

providing on said platform a heavy duty crane of size and capacity sufficient for offshore construction, pipelyaing and like operations and having a boom capable of performing loading and unloading operations over at least one barge side and over a major portion of the working platform extending longitudinally of the barge; and

providing such columns with configurations and areas and located at such distances from the barge longitudinal roll axis and barge transverse pitch axis so that when said barge is used in high draft semisubmerged operating condition the columns maintain the barge'"'"'s metacenter above the barge'"'"'s center of gravity during operations of said crane in accordance with the size and capacity of such crane and also so that the columns cause greater righting moment about the barge'"'"'s transverse pitch axis than about the barge'"'"'s longitudinal roll axis;

providing a plurality of longitudinally spaced means reinforcing the structural relationship of said hulls, platform and columns, including substantially transversely extending members interconnecting the hulls adjacent uppermost portions thereof;

providing ballast compartments in said hulls of sufficient capacity to ballast said barge to alter its draft between a low draft hull-supported floating condition with the hulls having freeboard and a high draft semisubmerged column stabilized operating condition; and

providing means for ballasting said hull compartments when required for counteracting the angle of barge heel caused by crane operations when the barge is in column stabilized semisubmerged operating condition so as to adjust the attitude of said barge about its roll axis sufficient to maintain barge angle of heel within suitable limits during crane operations.

18. A method according to claim 17 wherein the centroids of said columns are located outboard of the longitudinal centerline of the associated hull.

19. A method according to claim 18 including forming at least one of said columns on each of said hulls with an elongated cross section with the column dimension extending in direction of the barge'"'"'s longitudinal axis being greater than the transverse dimension of such column.

20. A method according to claim 19 including forming all of said columns with an oblong cross section with column dimension which extends in direction of the barge'"'"'s longitudinal axis being greater than the transverse dimension of such column.

21. A method according to claim 17 including forming a plurality of ballast compartments spaced transversely within each hull as well as a plurality of ballast compartments spaced longitudinally within each hull.

22. A method according to claim 21 wherein the centroids of said columns are located outboard of the longitudinal centerline of the associated hull.

23. A method according to claim 21 including forming at least one of said columns on each of said hulls with an elongated cross section with the column dimension extending in direction of the barge'"'"'s longitudinal axis being greater than the transverse dimension of such column.

24. A method according to claim 23 including forming all of said columns with an oblong cross section with column dimension which extends in direction of the barge'"'"'s longitudinal axis being greater than the transverse dimension of such column.

25. The method according to claim 17 wherein:

the crane'"'"'s rated and anticipated load capacity and boom outreach length are such that when the crane is rotated in oeprational use when the barge is in high draft semisubmerged column stabilized condition with crane load and outreach of predetermined values such crane operation will cause substantial heel of said barge about its roll axis which if uncorrected would exceed the maximum slew limiting angle of said crane, said ballast means for counteracting such angle of heel caused by such crane operations providing adjustment during crane operations of the barge angle of heel about the barge roll axis sufficient to maintain the barge'"'"'s angle of heel during such crane operations within said slew limiting angle of said crane.

26. The method according to claim 25 wherein said ballast means for conunteracting the angle of heel additionally includes ballast means operable to transfer ballast directly from one hull to the other hull during crane load operating conditions to achieve such adjustment of barge attitude to maintain the barge'"'"'s angle of heel within said crane slew limiting angle.

27. The method according to claim 17 including providing ballast means for counteracting change in the angle of trim of the barge caused when said crane is operated in the direction of the barge'"'"'s longitudinal axis causing a high resultant moment with respect to the pitch axis of said barge so that the latter mentioned ballast means may provide a counter-moment for reducing the angle of trim of the barge about its pitch axis.

28. The method according to claim 17 including providing said crane on said barge adjacent one end thereof.

29. The method according to claim 28 including locating at least one column on each hull adjacent the end of said barge at substantially the same longitudinal position at which said crane is mounted and at a distance from the transverse centerline of said barge at least substantially the same as the distance between said transverse centerline and the crane'"'"'s axis of rotation.

30. The method according to claim 28 including providing structural support means including support members directly connecting between the base of said crane and each of said pair of hulls for at least partially structurally supporting said crane from said hulls.

31. The method according to claim 28 including providing the crane with a boom of such length that its end reaches adjacent the end of said barge opposite the end at which said crane is mounted when said boom is disposed in the rest position.

32. A method according to claim 28 including providing said crane with an axis of rotation lying in a vertical plane located substantially along the longitudinal roll axis of the barge.

33. A method according to claim 17 including providing at one of the longitudinal ends of the barge a hinged shear leg for additional heavy lifting purposes.

34. A method according to claim 17 including providing said columns with an effective height of at least twenty-three feet between said hulls and said working platform.

35. A method according to claim 34 including providing said columns with a substantially constant cross section throughout the effective height thereof.

36. A method according to claim 17 including providing a plurality of longitudinally spaced truss means interconnecting said working platform and hulls as part of said longitudinally spaced means reinforcing the structural relationship of said hulls, platform and columns.

37. The method according to claim 17 including forming said barge so that it has a length-to-width ratio such that the barge length is at least a plural number of times as great as the barge width.

38. A method of constructing a column stabilized semisubmersible barge for offshore construction, pipelaying and like uses comprising the steps of:

fabricating a pair of elongated hulls of oblong cross section and disposing said hulls 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 and roll axis of the barge;

fabricating a plurality of columns of substantially constant cross section throughout their effective height and disposing a plurality of such columns on each of said hulls extending upwardly therefrom;

fabricating a working platform;

connecting opposite end portions of said columns to said platform and to said hulls respectively for supporting said working platform in fixed spaced relation above said hulls at least in part by said columns, and forming said barge so that it is generally rectangular in plan with a pair of sides and pair of ends and the distance between the extremities of the barge along its longitudinal centerline being at least plural times as great as the distance between the extremities of the barge along its transverse centerline, and locating a pair of end columns on each hull on opposite sides of the barge pitch axis and spaced therefrom while locating at least another of such columns at an intermediate position on each hull;

providing on said barge platform a heavy duty crane of size and capacity sufficient for offshore construction, pipelaying and like operations and having a boom capable of performing loading and unloading operations over at least one barge side and over a substantial longitudinally extending portion of said working platform in direction of the barge roll axis; and

providing such columns with configurations and areas and locations at such distances from the barge'"'"'s longitudinal roll axis and transverse pitch axis respectively so that when said barge is used in high draft semisubmerged operating condition the columns maintain the barge'"'"'s metacenter above the barge'"'"'s center of gravity including during operations of said crane consistent with the size and capacity of such crane and also so that the columns cause greater righting moment about the barge'"'"'s transverse pitch axis than about the barge'"'"'s longitudinal roll axis;

providing a plurality of longitudinally spaced means reinforcing the structural relationship of said hulls, platform and columns, including substantially transversely extending members structurally interconnecting the hulls and disposable above mean water line when the barge is floated with said hulls having freeboard;

providing ballast compartments in said hulls of sufficient capacity to ballast said barge to alter its draft between a low draft hull supported floating condition with the hulls having freeboard and a high draft semisubmerged column stabilized operating condition, and including a plurality of ballast compartments spaced transversely within each hull as well as a plurality of ballast compartments spaced longitudinally within each hull;

providing means for ballasting said hull compartments for altering the attitude of the barge about the roll axis and pitch axis respectively during operations of said crane when the barge is in column stabilized semisubmerged operating condition so as to offset when required change of barge angle of heel and barge angle of trim respectively due to such crane operations.

39. A method according to claim 38 including locating the centroids of said columns on each hull outboard of the longitudinal centerline of such hull.

40. A method according to claim 39 including providing at least one of said columns on each of said hulls with an elongated cross section with the column dimension extending in direction of the barge'"'"'s longitudinal axis being greater than the transverse dimension of such column.

41. A method according to claim 40 including providing all of said columns with an oblong cross section with column dimension extending in direction of the barge'"'"'s longitudinal axis being greater than the transversely extending column dimension.

42. A method according to claim 38 including providing at least one of said columns on each of said hulls with an elongated cross section with the column dimension extending in direction of the barge'"'"'s longitudinal axis being greater than the transverse dimension of such column.

43. The method according to claim 38 including providing said last-mentioned ballast means with means also operable to transfer ballast directly from one hull to the other hull to adjust barge attitude about the roll axis during such crane operations in semisubmerged condition.

44. The method according to claim 38 including providing said crane on said barge adjacent one end thereof.

45. The method according to claim 44 including locating at least one column on each hull adjacent the end of said barge at substantially the same longitudinal position at which said crane is mounted and at a distance from the transverse centerline of said barge at least substantially the same as the distance between said transverse centerline and the crane'"'"'s axis of rotation.

46. The method according to claim 44 including providing structural support means directly connecting between the base of said crane and each of said pair of hulls for at least partially structurally supporting said crane from said hulls.

47. A method according to claim 44 including providing said crane with an axis of rotation lying in a vertical plane located substantially along the longitudinal roll axis of the barge.

48. A method according to claim 38 including providing at one of the longitudinal ends of the barge a hinged shear leg for additional heavy lifting purposes.

49. A method according to claim 38 including providing said columns with an effective height of at least twenty-three feet between said hulls and said working platform.

50. A method according to claim 38 including providing ballast means also operable to transfer ballast directly between said hulls during crane load operating conditions to adjust barge angle of heel.

51. A method according to claim 38 including providing a plurality of longitudinally spaced truss means interconnecting said working platform and hulls as part of said longitudinally spaced means reinforcing the structural relationship of said hulls, platform and columns.

52. A method according to claim 38 including providing a boom of such length that its end reaches adjacent the end of said barge opposite the end at which said crane is mounted when said boom is disposed in the rest position.