Pipe Laying Vessels

A pipe-laying system was based on a floating object as used on land, a barge or pontoon was provided with the following parts:

Pipe Storage Rack.Pipe storage ,Roller conveyor line.
Pipe welding street + weld checking station.
Pipe Trencher machine with 2-3 or 4 Caterpillars.
A&R heavy winch , abended and recovery of pipe.
Stinger arm , up to 50 mtr overboard arm.
First deliveries of ST for the A&R ,Trencher (PP200)HPU + Control beginning 1975.

Pipe Lay methods:The most common pipeline installation methods are theS-Lay, the J-lay and the Reel-Lay methods.

1) S-Lay: The S-lay method is based on that the pipe is deployed in a S. This done via a Stinger ,suitable for welded pipe joints with concrete coating in shallow and intermediate water depths. S-lay also has a very high production rate.

2) J-lay: With the J-lay method the pipe is deployed in a J , the J-lay is very suitable for deep waters. The advantage with this method is that the pipe is bent only once, at the sea-bed ,this improves the fatique life.

3) Reel-Lay: The Rigid pipe or Flexible tube can be spooled onto a Reel (05) in a continuous length. The pipe is then welded, tested and coated onshore, this saves quitte some times offshore. The Reel have a horizontal shaft or a vertical shaft (Caroussel (-54). Pipe diameters from 100-to 630 mm, handling/Laying with 15 knots speed. ST was involved in the large Reel onboard of cable layer Apache ,USA based.

4) Flex-Lay: A Flex-Lay installation is not suitable for installation of rigid pipe and is therefore often combined with other pipe-lay methods as well as high voltage power transmission cablelay. pag. 93 A Flex-Lay system consist mainly of a vertical ramp (tower)with one or more Tensioners and a chute or wheel on top of the tower, the tower position can be adjusted. Note : A book called Pipe Lay Techniques (A summary) can be purchased at Stouco Consultance BV (37 pages) for USA Dollar 350,- incl. sending ww scale.