Method of submarine pipe laying

Abstract

.Iadd.A method of laying pipe on the floor of a body of water to form a pipeline in which the pipe section to be joined is at all times securely and stably supported by a mobile frame such that, during alignment and engagement, the pipe is substantially free from the influence of wave and current action. A pipe section is first releasably attached to a mobile frame, then lowered to the floor where it is placed in a stable-fixed position on the floor generally aligned with but spaced from the end of the previously laid pipe. The end is then aligned with the pipeline by lateral and/or tilting movement of the frame, and then moved axially into engagement with the end of the pipeline. The alignment and engagement procedures may be observed, directed and/or controlled from a region at atmospheric pressure. The method may also include holding the engaged pipe section in a stable position while placing ballast material thereunder. After engagement, the frame is released from the section and returned to the surface..Iaddend. .Iadd.

I claim: 
     
       1. The method of laying pipe on the floor under a body of water, comprising the steps of: releasably securing a length of pipe to a mobile frame; lowering said frame and pipe in said body of water to a stable position wherein said frame is supported securely by and in fixed relation to said floor with said length of pipe generally aligned with but spaced from the end of a pipeline already on said floor; moving at least a portion of said length of pipe, laterally of its length and relative to said frame, while holding the same secured thereto and supported thereby to bring the axis of said length of pipe into a desired and stable relation to the axis of said pipeline; and then moving said length of pipe axially, relative to said frame while holding the same secured thereto and supported thereby, into engagement with the end of said pipeline to form a continuation thereof. 
     
     
       2. The method defined in claim 1 including the further steps of securely and stably supporting said frame from said floor at a plurality of spaced points and selectively tilting said frame relative to said points to further control the relative alignment between said length of pipe and said pipeline. 
     
     
       3. The method defined in claim 1 including the further steps of, finally, releasing said length of pipe from said frame and lifting said frame to the surface of said body of water. 
     
     
       4. The method defined in claim 1 including the steps of detecting the relative positions of said length of pipe and said pipeline from a region at atmospheric pressure; and controlling said lateral and axial movements of said pipe from said region. 
     
     
       5. The method defined in claim 1 including the subsequent steps of placing ballast material between said length of pipe and said floor; and thereafter releasing said length of pipe from said frame.