Sub-sea pipeline to support the allied forces during WW2
The first offshore pipeline, with a length of almost 70 km, was constructed in the Bristol Channel in the south west of the UK.It was constructed in 1942 as a test for installing a pipeline in the English Channel between the UK and France to support allied forces after their landings during D-day in France. The whole project was called PLUTO (Pipe Line Under The Ocean) . Finally 17 pipelines were installed in the English Channel during this project of which were 11 lead pipelines and 6 steel pipelines.
More info on the PLUTO project
Brown & Root
The first commercial "offshore" pipeline was constructed by Brown & Root 1954 in the Gulf of Mexico. It was a 10 inch, concrete coated gas pipeline of 16 kilometer length which was laid at a depth of 4 to 10 meters. The speed of laying was approximately 800 meters per day and the crew worked only during daylight. Later Brown and Root made adaptations like building a ramp to allow the pipeline to approach the ocean floor more gently. This was further developed with a "stinger" used in today's offshore pipeline operations.
The first purpose build lay barge was build in 1958, also by Brown and Root.
Submarine Pipelines Ltd. was responsible for the development of controlled flotation pipe laying technology--pulling the pipeline out from shore supported by pontoon barges. The fixed reel pipe laying barge was developed in 1961. The development of the reel ship in 1975.
These three inventions come together in the O-lay method with the added technical feature that the pipeline will be bend only in its elastic area into a spiral to keep the pipeline in an original round shape without deforming the steel in the plastic area. The spiral is compared to a single stretch of pipe relatively compact and makes the transport to the new pipeline installation location easy.