What is a J-lay system?
J-lay is used to install rigid pipelines in deep water. With a J-lay system, pipe stalks, consisting of up to six pipes with a total length of 72m, are upended and welded to the seagoing pipe in a near vertical ramp. The ramp angle is adjusted so that it is in line with the pipe catenary to the seabed.
Why Stinger is required when S-Lay of a pipeline installation is to be used?
The purpose of the stinger in the S-lay configuration is to control the deflection of the pipe in the over-bend region above the pipeline inflection point in order to return the angle of the pipeline at the surface to the horizontal.
What is pipelay barge?
Pipelay vessels are any ships that install pipe on the ocean floor. These ships are purpose built for this process, carrying, welding, and laying pipe thousands of meters under the ocean surface. The reel method can be used on pipes 100-400 millimeters in diameter for lengths of up to 90 kilometers.
What is a reel-lay vessel?
– Reel-lay method Reel-lay and carousel-lay are used for rigid and flexible pipes: large lengths of pipe are welded, tested and coated onshore and then spooled on vertical reels or horizontal carousels on board the lay vessel. During pipelay the pipe is unspoooled from the reel or carousel.
What is the stinger on a pipe lay barge?
A new form of pipe support structure, or stinger, has been designed for laying pipelines offshore from a pipe-laying barge. In all expect very shallow water some form of support structure. Commonly called a stinger, is necessary to avoid excessive bending and possibly buckling a pipe.
What is a reel lay vessel?
What does a cable layer ship do?
A cable layer or cable ship is a deep-sea vessel designed and used to lay underwater cables for telecommunications, electric power transmission, military, or other purposes. Cable ships are distinguished by large cable sheaves for guiding cable over bow or stern or both.
How a pipeline is laid?
The process uses a pipe-laying vessel with a tower in which the individual pipes are welded to a string, followed by testing and field coating. In a close to vertical position, the finished string is then lowered into the water, while the vessel moves ahead at a slow speed.
How do you lay a pipeline?
Pipeline Construction: Step by Step Guide
- Step 1: Construction Staging Areas & Storage Yards.
- Step 2: Clear Cutting the ROW.
- Step 3: Excavating the Trench.
- Step 4: Pipe Transport, Stringing, & Assembly.
- Step 5: Obstacles: Roads & Streams.
- Step 6: Testing & Restoration.
What type of pipe lay is used in shallow water?
S-lay method Due to its high production rate and the possibility to install concrete coated pipe, S-lay is extremely suitable for pipe installation in shallow and intermediate waters. Larger water depths are equally possible but require a very long stinger, turning S-lay into a less practical and efficient solution.
Why is J lay the best pipelaying method?
This reduced amount of bending is beneficial for installing pipelines that are sensitive to fatigue. Compared to other lay methods, J-lay has a relatively low production rate due to the single position welding of the pipe. The J-lay method is less suitable for shallow waters as this requires a departure angle close to horizontal.
What’s the difference between a lie and a lay?
Lie and lay both have many definitions, but they’re most often confused where lie means to recline and lay means to put down. But the distinction is simple: Lay needs an object —something being laid—while lie cannot have an object. For example, you might lay a book on the table, lay a sweater on the bed, or lay a child in her crib.
What’s the difference between OSI Layer 1 and 3?
Layer 1 (Network Access): Also called the Link or Network Interface layer. This layer combines the OSI model’s L1 and L2. Layer 2 (Internet): This layer is similar to the OSI model’s L3. Layer 3 (Transport): Also called the Host-to-Host layer.
How are network layers explained in Computer Science?
The Network Layers Explained [with examples] In computer science, the concept of network layers is a framework that helps to understand complex network interactions. There are two models that are widely referenced today: OSI and TCP/IP. The concepts are similar, but the layers themselves differ between the two models.