Western Gear Corporation

Duncan Bell

David E Olson

Allen E Peirce

Jack L Odell

John P Veale

Donald A Swanson

A system for measuring and displaying the side and top profiles of an underwater pipeline as the pipeline is being laid on the sea floor by a pipe laying vessel. The profiles are determined by sequentially measuring the position of points spaced apart along the pipeline with respect to a point on the vessel. The measurements are accomplished by sequentially transmitting an acoustic signal from three, non-colinear transducers. The acoustic signals from each transmission is detected by a plurality of receivers spaced apart along the pipeline. As each receiver detects a transmission it produces an indicating signal on a pair of electrical conductors which are connected to the vessel and all of the receivers on the pipeline. The elapsed time between a transmission from a given transducer and detection of that transmission by each receiver is an indication of the distance between the transducer and each receiver. After all three transducers have interrogated the receivers, the three-dimensional position of each receiver is known, and the pipeline profile as viewed from the top and side can then be platted. Examination of the pipeline profile indicates the stress along the pipe so that the pipeline tension, or barge yaw attitude, can be adjusted to prevent damage to the pipeline.

Method and apparatus for adjusting the tension of an underwater pipeline

A system for measuring and displaying the side and top profiles of an underwater pipeline as the pipe line is being laid on the sea floor by a pipe laying vessel. The profiles are determined by sequentially measuring the position of points spaced apart along the pipeline with respect to a point on the vessel. The measurements are accomplished by sequentially transmitting an acoustic signal from three, non-colinear transducers. The acoustic signals from each transmission is detected by a plurality of receivers spaced apart along the pipeline. As each receiver detects a transmission it produces an indicating signal on a pair of electrical conductors which are connected to the vessel and all of the receivers on the pipeline. The elapsed time between a transmission from a given transducer and detection of that transmission by each receiver is an indication of the distance between the transducer and each receiver. After all three transducers have interrogated the receivers, the three-dimensional position of each receiver is known, and the pipeline profile as viewed from the top and side can then be platted. Examination of the pipeline profile indicates the stress along the pipe so that the pipeline tension, or barge yaw attitude, can be adjusted to prevent damage to the pipeline.

Method and apparatus for determining the profile of an underwater

An elongated pipe is held in a first constant tension mechanism and then, while the tension is maintained, the pipe load is shifted to a second constant tension mechanism by automatically correlating the declining tension force of the first constant tension mechanism with the increasing tension force of the second constant tension mechanism until the pipe is completely shifted to the second constant tension mechanism.

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Stanwood, WA, United States of America

Duncan Bell