| 摘要 |
<p>During recovery of an offshore pipeline (1), or cable, to a floating vessel (10) for repair, for example, the pipeline is secured to a hang-off clamp (2) connected to a vessel. Due to the motion of the vessel, oscillating bending moments can be caused in the pipeline below the clamp (2), and depending on the seastate, pipeline fatigue can result. To reduce these bending moments an auxiliary member is employed which restricts 'radial' movement of the pipeline below the clamp (2), thus enabling repairs to be carried out under more extreme sea conditions than hitherto. The auxiliary member comprises an elongate element, such as a pipe (4), whose upper end is fixed to the vessel (10) and whose lower end carries a member (7) connecting it to the pipeline (1). Axial movement of the pipeline with respect to the connecting member (7) is permitted. The auxiliary member is designed to have predetermined amount of flexibility, this being provided in particular by flexibility of the pipe (4), and it thus restricts the amount of radial movement of the pipeline which is permitted below the clamp (2), accordingly. Such an auxiliary member can also be used as a stinger during pipeline laying, for reducing bending moments during the lay.</p> |
