Iran has long boundaries beside the Persian Gulf and Oman sea, and it is the only country, which has the most and longest coast at north side of Persian Gulf .Because of the South Pars gas field region which contains a large number of oil wells oil well so it is normal that the countries in the area are so economically depended on oil and gas industries. Besides extracting oil , oil production is included saving and transporting oil and gas, since the great volume of oil & gas, transportation is very important subject in oil and gas industry .One of the most efficient and common ways in fluid transportation (specially in the sea) is using pipeline at sea bed. Beside oil & gas , Sub sea pipelines can also be used for other fluids transportation like liquid water. At first, sea bed pipeline is very technical and expensive so after installation with suitable protection will be applied to them. Suitable design is important in this type of pipeline and the coasts would be reduced so much in a good and safe design . The paper's goal is essentially to introduce the best design for pipeline as a result it offer to use a new method in pipe laying at submarine .This method is using buoy system in under sea pipelines. as follows.

Sub sea pipeline, buoy system, related equations, Assaluyeh coasts, formulations