offshore sulphur mine in the Gulf of Mexico. The hot pipeline is insulated within an outer 

 casing, and is to be entrenched in the bottom sediments composed in part of fine sand and 

 silt and the remainder cohesive clay, for hurricane protection. The sediment properties are 

 examined along the pipeUne route, and the vertical stability of the pipeline is investigated 

 with respect to pipe buoyancy and sediment properties. The thermal stability of the pipeline 

 is studied with respect to possible buckling due to thermal expansion between the fixed 

 ends to the pipeline, and subsidence of the Une due to thermal osmosis of the clay and 

 convection currents in the sand induced by the flow of heat from the pipeline to the 

 sediments. 



230. WILSON, B. W., "Anticipated Hurricane Effects on a Submarine Pipeline," Proceed- 

 ings of the International Association for Hydraulic Research Congress, 1963, 

 pp. 327-350. 



231. WILSON, J. F., and CALDWELL, H. M., "Force and StabUity Measurements on 

 Models of Submerged PipeUnes," Offshore Technology Conference, Paper No. OTC 

 1224, Vol. I, Apr. 1970, pp. I747-I758. 



Keywords: Current forces, Submerged pipeline 



A laboratory investigation of current-induced forces on submarine pipeUnes anchored 

 just above the ocean floor is discussed. Lift and drag forces and vibrations induced by eddy 

 shedding were studied for two parallel pipes located close to the sea floor. The effects of 

 horizontal spacing between the parallel pipes, vertical spacing from the ground plane, and 

 the orientation angle of the pipeUne with respect to the current direction were observed. 

 The experimental results were plotted and compared with available data for double and 

 single pipehnes with the ground plane absent. 



232. WILSON, R. O., and MARTIN, M. R., "Deepwater Pipelining for Central North Sea," 

 Offshore Technology Conference, Vol. II, Apr.-May 1973, pp. II305-I1314. 



Keywords: Construction methods, Ekofisk, Norway 



The construction of an oil pipeline system in the Ekofisk Field in the central North 

 Sea is reviewed. The pipeline construction equipment and methods used in the project are 

 described, including special alterations made to the lay barge; pipeUne-tensioning tech- 

 niques; pipe connections, risers, and special pipe-handhng techniques; trenching methods; 

 saturation diving operations; and surface position control techniques. Several developments 

 and improvements in pipelaying technology for future projects in rougher and deeper water 

 are also discussed, including special lay barges, improved tensioning techniques, automatic 

 pipe-joining methods, new diving systems, and improvements in logistical planning and 

 implementation on pipeline projects. 



233. YAMAMOTO, T., NATH, J., and SLOTTA, L., "Wave Forces on Horizontal Sub- 

 merged CyUnders," BuU. No. 47, Oregon State Uruversity, Corvallis, Greg., Apr. 1973. 



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