An offshore vessel that helps in the laying and setting of pipelines on the ocean floor is called as pipe laying vessel. A pipelayer enables the smooth continuity of operations from the high seas’ drilling zones to the processing plants situated inshore, and as such is an indispensable cog in the entirety of the offshore oil excavation operations.
However the scope of a pipelay vessel not only includes vessels utilised for the above specified operational purpose but also encompasses all those pipelayer ships that are applied for generic but equally vital sub-water pipelaying operations.
Pipelayer Ship: Features and Characteristics
Denoted as a ‘particularised ship’ to be utilised in the high seas, a pipelayer ship has several structural peculiarities like the incorporation of state-of-the-art and up to-date technological gadgetries like crane systems with really immense towing capacitances and DP systems.
The presence of these gadgetries becomes necessary as they help to facilitate optimal sub-water pipe positioning operations, irrespective of the water zone where the operations are being carried out.
Another major constructional feature of pipe laying ships is that their structural designing is unique and as per their mode of sub-water pipe positioning. As such, the nature of each of the major variances of these vessels can be explained as follows:
- Certain pipelay vessels have a mechanism which allows the necessary length of pipes to be rolled onto it like a spool. During pipe positioning operations, the spools of pipes are unrolled and laid out as required to suit the operational needs.
- A pipelay vessel that helps in the positioning of sub-water piping by way of the ‘S-laying’ methodology is referred to as an ‘S-laying pipe laying ship.’
- Pipelayers that employ the ‘J-laying’ methodology of positioning sub-water piping are denoted as ‘J-laying pipe laying vessels.’
The piecing of the necessary length of the sub-water piping in both the latter categorisations of pipe laying ships is carried out within the confines of the vessel, unlike in the primary classification where the piecing of the required piping is carried out inshore so as to economise the operational costs.
Majorly there are three methodologies of pipelaying which can be employed. Each of the same can be briefly elaborated as thus:
- The ‘S-laying’ pipelayer methodology refers to the S-shaped arc taken by the piping once it’s let up from the vessel to be positioned suitably. The position of the mechanism aboard the vessel laying out the pipes in the water is completely flat which allows the pipes to take the unique S-shaped curve thus prominently indicating the methodology employed.
- The ‘J-laying’ methodology refers to the J-shaped arc taken by the piping as it is being laid out by the vessel. In order to obtain the singular J-shaped curve, the pipe laying mechanism on the vessel is positioned perpendicularly which enables to control the curve of the pipe as it is lowered into the required depths of the water.
- The last methodology of pipelaying involves the usage of towing vessels to place the pipelines on the water surface, supported by buoys. In order to enable the pipes to reach their sub-water depths, after the pipes are suitably placed in the designated water area, the supporting buoys are cast off.
This method of pipe positioning is highly effective in all kinds of water zones, irrespective of the depth of the water.
An offshore vessel like the pipelay ship has helped to ease the pressure on the constancy of supply to meet the urgency of the demands. Through these vessels, certain maritime operations have become even more feasible than when they initially pioneered. Pipe laying ships have therefore become one of the biggest testimonies of technological advancements to further the cause of vital marine operations.