Method and apparatus for adjustably supporting a pipeline relative to a lay vessel

DETAILED DESCRIPTION Brief Overview Referring now to FIGS.
1 and 2 of the drawings, examples of support shoes of the prior art can be contrasted with support shoes of the present invention as the support shoes would appear schematically in their operative environments.
In both illustrations the support shoes are mounted on ramps 10 of lay vessels 12.
The lay vessels in this case are of the type referred to as barge hull lay vessels so hereinafter the lay vessels will be referred to merely as lay barges.
It should be emphasized, however, that the invention is also amenable to use with other lay vessels such as ship hull and semi-submersible lay vessels.
Attached to each lay barge is a stinger 14 which serves to support a pipeline 16 as it passes downwardly through a body of water 18 and onto a floor 20 of the body of water.
The pipeline 16 is assembled on the ramp of the lay barge and in moving to the stinger 14 passes through a dynamic tensioner 22 which serves to tension the pipeline.
Tensioning reduces the necessary length of the stinger and correspondingly increases the permissible free standing height of the pipeline from the floor of the body of water 20 to the point of the pipeline initially supported by the stinger.
As should be readily apparent from FIG.
1, support shoes of the prior art 24 each include a suitable member 23 which actually contacts the pipeline and a telescopic, vertically oriented stanchion 24 which interconnects the ramp of the lay barge and the member 23 contacting the pipeline.
The stanchions 24 of these support shoes are commonly comprised of hydraulic cylinder and guide sleeve assemblies which extend through openings in the ramp.
This aspect of the support shoes of the prior art is clearly illustrated in FIG.
1.
As the pipeline 16 moves relative to the support shoes of the prior art, considerable drag is exerted on the portions thereof contacting the pipeline.
It can be appreciated from FIG.
1 that drag developed may introduce bending moments of considerable magnitude in the upright stanchions supporting the pipeline