150. LAMPIETTI, F. J., "Pendulation of Pipes and Cables in Water," Journal of Engineer- 

 ing for Industry, Aug. 1964, pp. 299-304. 



Keywords: Drilling operation. Finite-difference method. Wind and wave forces 



A finite- difference method is described and formulated for calculating the lateral 

 motions of pipes and cables hanging below a ship due to the continuous displacement of the 

 ships by the forces of winds and waves. The method is intended for calculation with digital 

 computers and can be used to solve problems for the condition of a fixed lower end of the 

 pipe or cable, as with drilling operations with the tip well down below the sea floor, or for 

 the condition of a free lower end, as with the problem of reentering a drill hole on the ocean 

 floor, or the accurate emplacement of the anchors for deep-moored positioning buoys. 



151. LANGNER, C. G., "The Articulated Stinger: A New Tool for Laying Offshore 

 PipeUnes," Offshore Technology Conference, Paper No. OTC 1073, Vol. 11, May 1968, 

 pp. II37-n46. 



Keywords: Articulated stinger. Lay barge 



Paper describes a pipe support structure or stinger designed for laying offshore 

 pipehnes from a lay barge. The stinger consists of several adjustable buoyant segments 

 connected in series by special liinge joints which provide a limited degree of vertical, lateral, 

 and torsional flexibihty. The advantages of this articulated stinger over the conventional 

 type of straight, stiff stinger are discussed. Vertical stinger flexibUity, in combination with 

 apphed pipe tension, increases the water depth capabiUty of the stinger, and reduces the 

 required stinger length. Lateral and torsional flexibihty increases the weather capability of 

 the stinger. The use of the articulated stinger to lay pipelines in deep water is discussed and 

 illustrated. The performance of the articulated stinger in model tests and a prototype 

 situation are also briefly discussed. 



152. LAROCK, J. B., "Discussion of Hydrodynamic Forces on a Submarine Pipeline," 

 Journal of the Pipeline Division, Vol. 93, No. PL3, Nov. 1967, pp. 75-77. 



153. LAWRENCE, J. B., "Latest Developments in Marine Pipe Laying," The Boat Work, 

 Vol. 24, No. 3, Mar. 1967. 



154. LEDFORD, R. C, "Design of Submarine Pipelines for Stabihty," The Petroleum 

 Engineer, Vol. 25, No. 5, May 1953, pp. D70-D76. 



Keywords: Pipehne coating. Submarine pipeUne 



Article discusses the problem of providing the correct weight coat to a submarine 

 pipehne to keep it in place under varying bottom conditions. The pipes must be designed to 

 remain in an equilibrium condition when buried. If the pipe and weight coating are too 

 light, the pipe wiU rise out of its trench and be exposed to damage by wave and current 

 forces, dragging anchors, etc. If the pipe is too heavy, it may sink lower into the bottom 

 sediments, possibly resulting in excessive stresses which also cause damage to the pipeUne. A 

 summary of the results of tests carried out to determine the minimum thickness of concrete 

 coatings for specific requirements in submarine pipelines is also included. 



36 



