Abstract: A method of joining pipes to produce an underwater pipeline on a firing line includes supplying the firing line with pipes having previously roughened end portions; welding the end portions of adjacent pipes to form cutbacks, each of which is defined by two end portions, and by an annular weld bead between the two end portions; cleaning, by cryogenic blasting, the outer surface of each cutback; and forming a protective joint coating about each cutback.

Abstract: Process for the towing of underwater pipelines by means of head tugs for the pulling and tail tugs for the counter-pulling characterized in that it is effected by the use of a set of equipment, connected to the pipeline itself, including floats, of which at least a part has a variable buoyancy or partially variable buoyancy, which, when placed in a pre-established position and at pre-established intervals, provide a graded buoyancy to the pipeline in relation to the distance from the bed so as to obtain a “festoon” configuration of the pipeline, i.e. with suspended sections of pipeline, in correspondence with the floats, alternating with resting sections.

Abstract: Process for the towering of underwater pipelines by means of head tugs (R) for the pulling and tail tugs for the counterpulling characterized in that it is effected by the use of a set of equipment (A), connected to the pipeline (C) itself, substantially containing floats (G), of which at least a part has a variable buoyancy or partially variable buoyancy, which, when placed in a pre-established position and at pre-established intervals, provide a graded buoyancy to the pipeline in relation to the distance (f) from the seabed (F) so as to obtain a “festoon” configuration of the pipeline, i.e. with suspended sections of pipeline, in correspondence with the floats, alternating with resting sections.