What Jobs Are Done With Dynamic Positioning? – Pt. 3 Sean Total Views: 266 August 27, 2010 Moving on with our series; What Jobs Are Done With DP? Make sure to read Part 1 & Part 2 as well!  All comments are welcome. Pipe Lay Laying Pipe subsea is a much more active form of DP & installations come in different forms.  You may see a simple hard lay style pipe barge or an enormous flexible lay vessel, such as Allseas “Solitaire”. This style of work requires the operator to be constantly making adjustments to the vessels position using the DP console. Types of Pipelay As it concerns DP vessels, there are 3 styles of pipelay that you may encounter:  S-Lay, J-Lay & Flexible Reel S-Lay If it is an S-Lay installation then the vessel will move forward one pipe length (12m or 24m) every few minutes so that a new piece can be welded on to the end of the line.  Meanwhile, the last joint welded will move down the assembly line where it gets X-Rayed & Mag Particle tested, or some other type of NDT. The name is derived from the fact that the pipe makes 2 bends, forming an S shape, on its way to the sea floor. The pipe will be fed into the water off of a Stinger, which extends far past the stern.  This allows the pipe to be controlled as it is deployed, as well as controlling the curvature made by the pipe as it enters the water. J-Lay With a J-Lay installation, the pipe is lifter into an installation tower where it is welded in line.  The angle of which the pipe enters the water can now be much steeper & with reduced stress on the pipeline.  This allows installation in much deeper water. Flexible Reel This style is used to install either small diameter or flexible pipe.  The welding of the pieces is done ashore.  They are then rolled onto the reel, which is installed onboard the vessel in either a horizontal or vertical fashion.  If installed horizontally then the pipe will pay off the reel in an S-Lay fashion &