Laying Pipeline

This is a pretty cool video of a pipe laying ship. That's a LOT of machinery and work going on there.
I don't understand is it seems as though half of the ship is dedicated
to processing short sections of pipe into longer sections, which are then sent to yet another separate welding station to be welded into the actual string. Wouldn't it be so much cheaper to have a shop on shore to weld the short sections together, rathern than having two separate welding operations on the ship?

http://www.youtube.com/watch?v=EyrdjqEiTZc

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Interesting video, thanks for posting. As to why not do more welding on shore, I'd guess it has to do with the hazards of handling big, heavy objects at sea. The video shows very placid water conditions. In rough weather, longer sections of pipe would be very much harder to move between the supply barge the the ship using a crane.
bob prohaska
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On Sun, 24 Oct 2010 17:42:31 -0700 (PDT), Cross-Slide

Thanks for the post. That was way cool. Here is the link to part two of the vid:

http://www.youtube.com/watch?v
Ü2i06331qQ
As to your question: Those pipe sections look about one flatbed rail road car in length. Start at pipe manufacturing plant....load to flatbed rail car.....rail trip to port....port loads pipe sections to transport barge......transport barge to assembly ship. The rail car is the limiting factor in pipe length.
They weld two short lengths together in one pass using the submerged arc method. As far as work flow, this one pass welding is quicker (and probably cheaper) then the multi-pass welds done further down the line. This assures a ready supply of pipe into the final product line even accounting for whatever down time may happen to occur in the initial preparation area (bringing pipe up from the hold and welding the two sections together).
It looks like the engineers that designed this whole process pretty well knew what they were doing. I am impressed with the ingenuity of them damn humans sometimes. Dave
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On Oct 25, 6:51 am, snipped-for-privacy@is.invalid wrote:

I was impressed because for once, there is a video that explains what is happening, and shows the processes involved, the work flow and the support to make it possible.
Thanks for the explanation about the two types of welding processes. The first stage, they can rotate the pipes as they weld them. The submerged arc never has to be inverted. The main line welding, that does not appear to be an option.
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