Claims
- 1. A flotation member for laying pipeline on an underwater surface from a floating vessel having a pipeline work deck elevated above the mean waterline comprising:
- an elongated base structure comprised of a pair of transversely spaced hulls, at least a portion of said hulls converging toward one another in one of the fore and aft directions;
- a plurality of elements upstanding from said hulls with at least a portion of said elements comprised of a plurality of stabilizing columns located on opposite sides of the pitch and roll axes of the member;
- means for submerging said base structure and portions of said upstanding elements below the waterline to obtain a high draft floating condition, the displacement of the submerged base structure and portions of said upstanding elements being sufficient to maintain the member buoyant in a pipeline portion supporting condition with the mean waterline located intermediate the height of said columns;
- coupling means carried by said base structure adjacent its forward end for pivotally coupling the flotation member to the pipelaying vessel;
- and means carried by said flotation member for supporting a portion of a pipeline for translational movement therealong, said pipeline support means being located above said base structure at elevations of decreasing height relative to said base structure in a forward to aft direction along said flotation member, the pipeline support means being adapted to receive pipeline payed out from the elevated work deck of the pipelaying vessel.
- 2. Apparatus according to claim 1 including means for varying the submergence of the flotation member in the high draft condition to alter the natural period of the flotation member to preclude amplification of flotation member motion due to interaction of wave and flotation member motion.
- 3. Apparatus according to claim 1 wherein said stabilizing columns have a substantially uniform cross-sectional area throughout their height.
- 4. Apparatus according to claim 1 wherein said submerging means includes means for ballasting and deballasting said base structure.
- 5. Apparatus according to claim 4 wherein each of said hulls include a plurality of compartments, valve means associated with said compartments for introducing water ballast into and expelling water ballast from said compartments.
- 6. Apparatus according to claim 1 wherein said support means comprises a plurality of rollers disposed at longitudinally spaced positions along said stinger and lying substantially coincident with the longitudinal centerline of the stinger.
- 7. Apparatus according to claim 6 wherein at least a pair of said columns are carried by each of said hulls, a plurality of support struts extending between laterally adjacent columns, said rollers being disposed on said support struts.
- 8. Apparatus according to claim 1 including said vessel, said coupling means coupling said flotation member to the aft end of said vessel to position the flotation member for receiving pipeline payed out from said vessel.
- 9. Apparatus according to claim 8 wherein said vessel has a work area adjacent one side of the vessel for assembling pipe sections, said member being coupled to said vessel to lie in substantial longitudinal alignment with said one vessel side.
- 10. Apparatus according to claim 8 wherein said vessel has a work area substantially along the centerline of said vessel, said member being coupled to said vessel such that the centerlines of said vessel and said member lie in substantial longitudinal alignment one with the other.
- 11. Apparatus according to claim 8 wherein said vessel includes a base structure and a plurality of columns upstanding from said base structure, and means for ballasting and deballasting said vessel between high and low draft conditions, said vessel being column stabilized in the high draft condition.
- 12. Apparatus according to claim 11 wherein said vessel has a work area adjacent one side thereof for assembling pipe sections, said vessel hull structure including a pair of elongated hulls spaced one from the other on opposite sides of said vessel, and means carried by the aft portion of the one hull on the same side of said vessel as said work area and cooperable with said coupling means on said stinger for releasably connecting said flotation member to said vessel.
- 13. Apparatus according to claim 11 wherein said vessel has a work area substantially along the centerline of said vessel for assembling pipe sections, said vessel hull structure including a pair of elongated hulls spaced one from the other on opposite sides of said vessel, and means carried by the aft portions of said hulls and cooperable with said coupling means on said flotation member for releasably connecting said flotation member to said vessel.
- 14. Apparatus according to claim 8 wherein the natural period of said flotation member and the pipeline portion carried thereby substantially match the natural frequency of said vessel.
- 15. Apparatus according to claim 8 wherein said vessel and said flotation member and pipeline portion carried thereby have predetermined natural periods, and means for selectively ballasting and deballasting the flotation member to substantially match the natural period of the flotation member and pipeline portion carried thereby with the natural period of the vessel.
- 16. Apparatus according to claim 1 wherein at least a pair of said columns are carried by each of said hulls, said base structure being configured to float the member in a low draft condition with the base structure having freeboard, said submerging means including means for ballasting said hull to change the draft of the member from said low draft condition to said high draft condition.
- 17. Apparatus according to claim 1 wherein said base structure includes a keel spaced below said hulls, and means connecting said hulls and said keel one to the other.
- 18. Apparatus for laying pipeline on an underwater surface comprising;
- a floating vessel having a pipeline work deck elevated above the mean waterline;
- a flotation member having an elongated base structure;
- a plurality of elements upstanding from said base structure with at least a portion of said elements comprised of a plurality of stabilizing columns located on opposite sides of the pitch and roll axes of said flotation member;
- means for submerging said base structure and portions of said upstanding elements below the waterline to obtain a high draft floating condition, the displacement of the submerged base structure and portions of said upstanding elements being sufficient to maintain the flotation member buoyant in a pipeline portion supporting condition with the mean waterline located intermediate the height of said columns;
- means carried by said base structure adjacent its forward end pivotally coupling said pipelaying vessel and said flotation member one to the other;
- and means carried by said flotation member for supporting a portion of a pipeline for translational movement therealong, said pipeline support means being located above said base structure at elevations of decreasing height relative to said base structure in a forward to aft direction along said flotation member, the pipeline support means being adapted to receive pipeline payed out from the elevated work deck of said vessel;
- said flotation member comprising the sole means for supporting the pipeline as it is payed out from said vessel. .Iadd.19. Apparatus for laying pipe on an underwater surface comprising:
- a floating vessel including a pair of elongated hulls disposed in spaced side-by-side relation;
- a working platform including a generally horizontally disposed pipeline work deck on which pipe sections are joined end to end one with the other and from which work deck the pipeline is payed out from the aft end of said vessel;
- means for supporting said platform in fixed spaced relation a predetermined height above said hulls including columns connected to said hulls and said platform, at least three of such columns being connected with each of the hulls on opposite sides of the roll axis of the vessel, at least one column on each hull being disposed adjacent the aft end of said hull;
- said elevated pipeline work deck on said platform and said columns being relatively disposed such that pipeline is payed out from said pipeline work deck and from the aft end of said vessel at an elevation no lower than the juncture of the upper ends of the aftmost columns on said hulls and the underside of said platform;
- the distance between the extremities of said vessel along its longitudinal centerline being substantially greater than the distance between the extremities of said vessel along its transverse centerline;
- said hulls having ballast compartments for ballasting said vessel to alter its draft between a low draft hull supported floating condition with the hulls having freeboard and a high draft semisubmerged column stabilized floating and pipelaying condition with said pipeline work deck elevated above the mean waterline whereby pipeline payed out from said elevated pipeline work deck and from the aft end of said vessel, when the vessel lies in said high draft pipelaying condition, curves downwardly toward the water as it extends through the air between the aft end of the vessel and a location spaced from said vessel at which the pipeline enters the water;
- said columns having predetermined cross-sectional areas and being located on the hulls to provide righting moments about the pitch and roll axes of said vessel when in high draft condition; and
- means connected to the aft end of said vessel and extending generally longitudinally therefrom for supporting at least the downwardly curved portion of the pipeline payed out from said elevated pipeline work deck and the aft end of said vessel which extends through the air between the aft end of the vessel and the location spaced from said vessel at which the pipeline enters the water, said support means including means for maintaining the radius of curvature of the downwardly curved pipeline portion greater than the radius of curvature which would permit bending stresses on the pipeline in excess of its allowable bending stress, said maintaining means including a plurality of discrete supports longitudinally spaced one from the other along said support means and arranged such that a curved line through successive ones of said supports has a radius of curvature greater than the radius of curvature which would permit bending stresses on the pipeline in excess of its allowable bending
- stress. .Iaddend. .Iadd.20. Apparatus according to claim 19 including means for adjusting the elevation of said supports relative to said work deck. .Iaddend..Iadd.21. Apparatus according to claim 19 including means for adjusting the elevation of said supports relative to the mean waterline, and means carried by said vessel and coupled to said adjusting means for controlling the elevation of said supports relative to the mean waterline from said vessel. .Iaddend..Iadd.22. Apparatus according to claim 19 including means for pivotally connecting said support means and said vessel adjacent the aft end of said vessel. .Iaddend..Iadd.23. Apparatus according to claim 19 wherein said work deck is located at an elevation at least 15 feet above the mean waterline when said vessel lies in said high draft condition. .Iaddend. .Iadd.24. Apparatus according to claim 19 including means for pivotally connecting said support means and said vessel adjacent the aft end of said vessel, said work deck being located at an elevation at least 15 feet above the mean waterline when said vessel lies in said high draft condition. .Iaddend..Iadd.25. Apparatus according to claim 19 wherein said supports include at least a forwardmost pair of longitudinally spaced supports for supporting the pipeline portion which extends through the air and which pair of supports lie at an elevation above the mean waterline, at least one additional support located aft of the forwardmost pair of supports on said support means for supporting a portion of the pipeline below the mean waterline and which latter support lies at an elevation below the waterline. .Iaddend. .Iadd.26. Apparatus according to claim 19 wherein said elevated pipeline work deck extends substantially along the centerline of said vessel and said pipeline support means extends substantially longitudinally along the centerline of the vessel extended from the aft end of the vessel. .Iaddend..Iadd.27. Apparatus according to claim 19 wherein said elevated pipeline work deck extends longitudinally substantially along one side of the centerline of said vessel, said pipeline support means extending longitudinally from the aft end of the vessel and from said one side of the vessel. .Iaddend..Iadd.28. Apparatus according to claim 19 including a crane located adjacent said one end of the vessel, said vessel including structure below said crane defining an opening through which the pipeline passes as the pipeline is transferred from the vessel to the support means. .Iaddend. .Iadd.29. Apparatus according to claim 24 wherein each of said hulls has top and bottom substantially planar horizontally disposed surfaces extending substantially perpendicular to a vertical plane through the longitudinal centerline of said vessel with the transverse horizontal dimension of each hull being greater than its vertical dimension for a major portion of the length of said hulls so as to provide increased mass resistance to movement of said hulls through water in a vertical direction when said vessel lies in said high draft column stabilized semisubmerged pipelaying condition, said columns being substantially constant in cross section for substantially their entire height between said platform and said hulls, at least one of said columns on each said hull having a dimension in the longitudinal direction greater than its dimension in the transverse direction, said maintaining means including a plurality of discrete supports longitudinally spaced one from the other along said pipeline support and arranged such that a curved line through successive ones of said supports has a radius of curvature which would permit bending stresses on the pipeline in excess of its allowable bending stress. .Iaddend. .Iadd.30. Apparatus for laying pipe on an underwater surface comprising:
- a floating vessel including a pair of elongated hulls disposed in spaced side-by-side relation;
- a working platform including a generally horizontally disposed pipeline work deck on which pipe sections are joined end to end one with the other and from which work deck the pipeline is payed out from the aft end of said vessel;
- means for supporting said platform in fixed spaced relation a predetermined height above said hulls including columns connected to said hulls and said platform, at least three of such columns being connected with each of the hulls on opposite sides of the roll axis of the vessel, at least one column on each hull being disposed adjacent the aft end of said hull;
- said elevated pipeline work deck on said platform and said columns being relatively disposed such that pipeline is payed out from said pipeline work deck and from the aft end of said vessel at an elevation no lower than the juncture of the upper ends of the aftmost columns on said hulls and the underside of said platform;
- the distance between the extremities of said vessel along its longitudinal centerline being substantially greater than the distance between the extremities of said vessel along its transverse centerline;
- said hulls having ballast compartments for ballasting said vessel to alter its draft between a low draft hull supported floating condition with the hulls having freeboard and a high draft semisubmerged column stabilized floating and pipelaying condition with said pipeline work deck elevated above the mean waterline whereby pipeline payed out from said elevated pipeline work deck at the aft end of said vessel, when the vessel lies in said high draft condition, curves downwardly toward the water as it extends through the air between the aft end of the vessel and a location spaced from said vessel at which the pipeline enters the water;
- said columns having predetermined cross-sectional areas and being located on the hulls to provide righting moments about the pitch and roll axes of said vessel when in high draft condition;
- means connected adjacent the aft end of said vessel and extending generally longitudinally therefrom for supporting at least the downwardly curved portion of the pipeline payed out from said elevated pipeline work deck which extends through the air between the aft end of the vessel and a location spaced from said vessel at which the pipeline enters the water, said support means including a flotation member having an elongated base structure, a plurality of elements upstanding from said base structure comprised of a plurality of stabilizing columns located on opposite sides of the pitch and roll axes of the member;
- means for submerging said base structure and portions of said upstanding elements below the waterline to a high draft floating condition, the displacement of the submerged base structure and portions of said upstanding elements being sufficient to maintain the member buoyant in a pipeline portion supporting condition with the mean waterline located intermediate the height of at least a plurality of said columns;
- coupling means carried by said base structure adjacent its forward end for pivotally coupling the flotation member to said vessel; and
- means carried by said flotation member for supporting the pipeline for translational movement therealong and at elevations of decreasing height relative to said base structure in a fore to aft direction along said
- flotation member. .Iaddend. .Iadd.31. Apparatus according to claim 30 wherein said elevated pipeline work deck extends substantially along the centerline of said vessel and said flotation member extends substantially longitudinally along the centerline of the vessel extended from the aft end of the vessel. .Iaddend..Iadd.32. Apparatus according to claim 30 wherein said elevated pipeline work deck extends longitudinally substantially along one side of the centerline of said vessel, said flotation member extending longitudinally from the aft end of the vessel and from said one side of the vessel. .Iaddend..Iadd.33. Apparatus according to claim 30 including a crane located adjacent said one end of the vessel, said vessel including structure below said crane defining an opening through which the pipeline passes as the pipeline is transferred from the vessel to said flotation member. .Iaddend. .Iadd.34. Apparatus for laying pipe on an underwater surface comprising:
- a floating vessel including a pair of elongated hulls disposed in spaced side-by-side relation;
- a working platform including a generally horizontally disposed pipeline work deck on which pipe sections are joined end to end one with the other and from which work deck the pipeline is payed out from one end of said vessel;
- means for supporting said platform in fixed spaced relation a predetermined height above said hulls including columns connected to said hulls and said platform with at least one column on each hull disposed adjacent the aft end of said hull;
- said elevated pipeline work deck on said platform and said columns being relatively disposed such that pipeline is payed out from said pipeline work deck and from the aft end of said vessel at an elevation no lower than the juncture of the upper ends of the aftmost columns on said hulls and the underside of said platform;
- the distance between the extremities of said vessel along its longitudinal centerline being greater than the distance between the extremities of said vessel along its transverse centerline;
- said hulls having ballast compartments for ballasting said vessel to alter its draft between a low draft hull supported floating condition with the hulls having freeboard and a high draft semisubmerged column stabilized floating and pipelaying condition with said pipeline work deck elevated above the mean waterline whereby pipeline payed out from said elevated pipeline work deck at the aft end of said vessel, when said vessel lies in said high draft pipelaying condition, curves downwardly toward the water as it extends through the air between the aft end of the vessel and a location spaced from said vessel at which the pipeline enters the water;
- said columns having predetermined cross-sectional areas and being located on the hulls to provide righting moments about the pitch and roll axes of said vessel when in high draft condition;
- means connected to the aft end of said vessel and extending generally longitudinally therefrom for supporting at least the downwardly curved portion of the pipeline payed out from said elevated pipeline work deck which extends through the air between the aft end of the vessel and a location spaced from said vessel at which the pipeline enters the water, said support means including means for maintaining the radius of curvature of the downwardly curved pipeline portion greater than the radius of curvature which would permit bending stresses on the pipeline in excess of its allowable bending stress, said maintaining means including a plurality of discrete supports longitudinally spaced one from the other along said support means and arranged such that a curved line through successive ones of said supports has a radius of curvature greater than the radius of curvature which permit bending stresses on the pipeline in excess of its allowable bending stress; and
- means for pivotally connecting said support means and said vessel adjacent the aft end of said vessel, said work deck being located at an elevation at least 15 feet above the mean waterline when said vessel lies in said
- high draft condition. .Iaddend. .Iadd.35. Apparatus according to claim 34 including means for adjusting the elevation of said supports relative to said support deck. .Iaddend..Iadd.36. Apparatus according to claim 34 including means for adjusting the elevation of said supports relative to the mean waterline, and means carried by said vessel and coupled to said adjusting means for controlling the elevation of said supports relative to the mean waterline of said vessel. .Iaddend. .Iadd.37. Apparatus according to claim 34 wherein each of said hulls has top and bottom substantially planar horizontally disposed surfaces extending substantially perpendicular to a vertical plane through the longitudinal centerline of said vessel with the transverse horizontal dimension of each hull being greater than its vertical dimension for a major portion of the length of said hulls so as to provide increased mass resistance to movement of said hulls through water in a vertical direction when said vessel lies in said high draft column stabilized semi-submerged pipelaying condition, said columns being substantially constant in cross section for substantially their entire height between said platform and said hulls, at least one of said columns on each said hull having a dimension in the longitudinal direction greater than its dimension in the transverse direction, said maintaining means including a plurality of discrete supports longitudinally spaced one from the other along said pipeline support and arranged such that a curved line through successive ones of said supports has a radius of curvature greater than the radius of curvature which would permit bending stresses on the pipeline in excess of its allowable bending stress. .Iaddend. .Iadd.38. Apparatus according to claim 34 wherein said elevated pipeline work deck extends substantially along the centerline of said vessel and said pipeline support means extends substantially longitudinally along the centerline of the vessel extended from the aft end of the vessel. .Iaddend..Iadd.39. Apparatus according to claim 34 wherein said elevated pipeline work deck extends longitudinally substantially along one side of the centerline of said vessel, said pipeline support means extending longitudinally from said one end of the vessel and from the aft side of the vessel. .Iaddend..Iadd.40. Apparatus according to claim 34 including a crane located adjacent the aft end of the vessel, said vessel including structure below said crane defining an opening through which the pipeline passes as the pipeline is transferred from the vessel to the support means. .Iaddend. .Iadd.41. Apparatus for laying pipe on an underwater surface comprising:
- a floating vessel including a pair of elongated hulls disposed in spaced side-by-side relation;
- a floating vessel including a pair of elongated hulls disposed in spaced side-by-side relation;
- a working platform including a pipeline work deck on which pipe sections are joined end to end one with the other and from which work deck the pipeline is payed out from one end of said vessel;
- means for supporting said platform in fixed spaced relation a predetermined height above said hulls including columns connected to said hulls and said platform, at least three of such columns being connected with each of the hulls on opposite sides of the roll axis of the vessel with a pair of such columns being located near respective opposite ends of each of said hulls on opposite sides of the pitch axis of the vessel and another of said columns being located at an intermediate position on each hull;
- the distance between the extremities of said vessel along its longitudinal centerline being substantially greater than the distance between the extremities of said vessel along its transverse centerline;
- said hulls having ballast compartments for ballasting said vessel to alter its draft between a low draft hull supported floating condition and a high draft semisubmerged column stabilized floating and pipelaying condition with said pipeline work deck elevated above the mean waterline whereby pipeline payed out from said elevated work deck at one end of said vessel when said vessel lies in said high draft condition curves downwardly toward the water as it extends through the air between said one vessel end and a location spaced from said vessel at which the pipeline enters the water;
- said columns having predetermined cross-sectional areas and being located on the hulls to provide righting moments about the pitch and roll axes of said vessel when in high draft condition;
- means for providing a significantly greater righting moment about the transverse pitch axis of the vessel than the righting moment about the longitudinal roll axis of the vessel when said vessel is in high draft semisubmerged operating condition, the latter means including at least three of the aforementioned columns connected with each of the hulls on opposite sides of the roll axis of the vessel with pairs of such columns being located near opposite ends of each of said hulls on opposite sides of the pitch axis of the vessel and another of said columns being located at an intermediate portion on each hull and with the configurations and areas of said columns and the distances of said columns from the longitudinal roll axis and transverse pitch axis of said vessel being such that in the vessel's semisubmerged operating condition the latter means provides a significantly greater righting moment about said transverse pitch axis than about said longitudinal roll axis; and
- means connected to one end of said vessel and extending generally longitudinally therefrom for supporting at least the portion of the pipeline payed out from said elevated pipeline work deck which extends through the air between said one vessel end and a location spaced from said vessel at which the pipeline enters the water, said support means including a flotation member having an elongated base structure, a plurality of elements upstanding from said base structure comprised of a plurality of stabilizing columns located on opposite sides of the pitch and roll axes of the member;
- means for submerging said base structure and portions of said upstanding elements below the waterline to a high draft floating condition, the displacement of the submerged base structure and portions of said upstanding elements being sufficient to maintain the member buoyant in a pipeline portion supporting condition with the mean waterline located intermediate the height of at least a plurality of said columns;
- coupling means carried by said base structure adjacent its forward end for pivotally coupling the flotation member to said vessel; and
- means carried by said flotation member for supporting the pipeline for translational movement therealong and at elevations of decreasing height relative to said base structure in a fore to aft direction along said flotation member. .Iaddend. .Iadd.42. Apparatus according to claim 41 wherein said elevated pipeline work deck extends substantially along the centerline of said vessel and said flotation member extends substantially longitudinally along the centerline of the vessel extended from said one end of the vessel. .Iaddend..Iadd.43. Apparatus according to claim 41 wherein said elevated pipeline work deck extends longitudinally substantially along one side of the centerline of said vessel, said flotation member extending longitudinally from said one end of the vessel and from said one side of the vessel. .Iaddend..Iadd.44. Apparatus according to claim 41 including a crane located adjacent said one end of the vessel, said vessel including structure below said crane defining an opening through which the pipeline passes as the pipeline is transferred from the vessel to said flotation member. .Iaddend. .Iadd.45. Apparatus according to claim 18 wherein said vessel comprises
- a pair of elongated hulls disposed in spaced side-by-side relation;
- a working platform spaced above said hulls a predetermined height and carrying said work deck;
- means for supporting said platform in fixed spaced relation above said hulls including columns connected to said hulls and said platform;
- the distance between the extremities of said vessel along the longitudinal centerline of said vessel being substantially greater than the distance between the extremities of said vessel along the transverse centerline of said barge;
- said hulls having ballast compartments for ballasting said vessel to alter its draft between a low draft hull supported floating condition and a high draft semisubmerged column stabilized floating condition;
- said columns having predetermined cross-sectional areas and being located on the hulls to provide righting moments about the pitch and roll axes of said vessel when in high draft condition;
- the area of said columns, the number thereof and the distance of said columns from the longitudinal and transverse centerlines of said vessel being such as to provide a greater righting moment about the transverse pitch axis than the righting moment about the longitudinal roll axis when said vessel is in high draft semisubmerged condition. .Iaddend..Iadd.46. Apparatus according to claim 18 wherein said pipeline support means are located to support the pipeline such that the radius of curvature of the pipeline lies within its allowable radius of curvature whereby rupture of the pipeline is avoided. .Iaddend..Iadd.47. Apparatus according to claim 18 wherein said pipeline work deck supports the pipeline at an elevation on the order of about 15 feet above the mean waterline at the location where the pipeline is transferred between said vessel and said flotation member. .Iaddend. .Iadd.48. A column stabilized semisubmersible pipelaying barge and pipeline support apparatus comprising:
- a pair of elongated hulls disposed in spaced side-by-side relation;
- a working platform spaced above said hulls a predetermined height including a pipeline work deck, and means on said work deck for securing pipe sections in end-to-end relation one to the other to form a pipeline extending generally parallel to the longitudinal centerline of said barge;
- means for supporting said platform in spaced relation above said hulls including columns connected to said hulls and said platform on opposite sides of the pitch and roll axes of said barge;
- the distance between the extremities of said barge along the longitudinal centerline thereof being substantially greater than the distance between the extremities of said barge along its transverse centerline;
- said hulls having ballast compartments for ballasting 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 floating and pipelaying condition with the pipeline work deck elevated above the mean waterline whereby pipeline payed out from said elevated pipeline work deck, when said barge lies in said high draft condition, curves downwardly toward the water as it extends through the air between said elevated pipeline work deck and a location at which the pipeline enters the water,
- said columns having predetermined cross-sectional areas and being located on the hulls to provide righting moments about the pitch and roll axes of said barge when in said high draft condition;
- an elongated pipeline support pivotally connected to said barge and extending generally longitudinally in a predetermined attitude relative to said barge for supporting at least the downwardly curved portion of the pipeline payed out from said elevated pipeline work deck which extends through the air between said barge and the location at which the pipeline enters the water, and
- means for maintaining said elongated pipeline support in said predetermined attitude relative to said barge thereby to maintain the radius of curvature of the downwardly curved pipeline portion greater than the radius of curvature which would permit bending stresses on the pipeline in excess of its allowable bending stress. .Iaddend. .Iadd.49. Apparatus according to claim 48 wherein the pivotal connection between said pipeline support and said barge lies at an elevation below said work deck and below the pipeline at like longitudinal location along said barge as the longitudinal location of said pivotal connection along said barge. .Iaddend..Iadd.50. Apparatus according to claim 49 wherein each of said hulls has top and bottom substantially planar horizontally disposed surfaces extending substantially perpendicular to a vertical plane through the longitudinal centerline of said vessel with the transverse horizontal dimension of each hull being greater than its vertical dimension for a major portion of the length of said hulls so as to provide increased mass resistance to movement of said hulls through water in a vertical direction when said vessel lies in said high draft column stabilized semisubmerged pipelaying condition. .Iaddend..Iadd.51. Apparatus according to claim 50 wherein said columns are substantially constant in cross section for substantially their entire height between said platform and said hulls. .Iaddend..Iadd.52. Apparatus according to claim 51 wherein said pivotal connection lies at an elevation below the elevation of said top hull surfaces. .Iaddend. .Iadd.53. Apparatus according to claim 48 wherein said pipeline work deck is generally horizontally disposed, at least three columns disposed on each said hull, said work deck and said columns being relatively disposed such that pipeline is payed out from said pipeline work deck at an elevation no lower than the juncture of the upper ends of the columns and the underside of said platform. .Iaddend..Iadd.54. Apparatus according to claim 48 wherein one of said three columns is disposed adjacent the aft end of said vessel, said work deck and said columns being relatively disposed such that pipeline is payed out from said pipeline work deck and from the aft end of said vessel at an elevation no lower than the juncture of the upper ends of the aftmost columns on said hulls and the underside of said platform, said pipeline support being pivotally connected to said barge adjacent its aft end and extending generally longitudinally therefrom for supporting at least the downwardly curved portion of the pipeline payed out from said elevated pipeline work deck and the aft end of said vessel which extends through the air between said barge and the location at which the pipeline enters the water. .Iaddend. .Iadd.55. Apparatus according to claim 54 wherein each of said hulls has top and bottom substantially planar horizontally disposed surfaces extending substantially perpendicular to a vertical plane through the longitudinal centerline of said vessel with the transverse horizontal dimension of each hull being greater than its vertical dimension for a major portion of the length of said hulls so as to provide increased mass resistance to movement of said hulls through water in a vertical direction when said vessel lies in said high draft column stabilized semisubmerged pipelaying condition, said columns being substantially constant in cross section for substantially their entire height between said platform and said hulls, at least one of said columns on each said hull having a dimension in the longitudinal direction greater than its dimension in the transverse direction, said maintaining means including a plurality of discrete supports longitudinally spaced one from the other along said pipeline support and arranged such that a curved line through successive ones of said supports has a radius of curvature greater than the radius of curvature which would permit bending stresses on the pipeline in excess of its allowable bending stress, said work deck being located at an elevation at least 15 feet above the mean waterline when said barge lies in said high draft column stabilized pipelaying condition. .Iaddend. .Iadd.56. Apparatus according to claim 55 including means for adjusting the elevation of said supports relative to said work deck. .Iaddend..Iadd.57. Apparatus according to claim 55 including means for adjusting the elevation of said supports relative to the mean waterline, and means carried by said vessel and coupled to said adjusting means for controlling the elevation of said supports relative to the mean waterline from said vessel. .Iaddend.
Parent Case Info
This application is a continuation-in-part of my copending application Ser. No. 22,634 filed Mar. 25, 1970.
US Referenced Citations (7)
Continuation in Parts (1)
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Number |
Date |
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Parent |
22634 |
Mar 1970 |
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Reissues (1)
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Number |
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064267 |
Aug 1970 |
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