An automated instrument for testing and monitoring oceanographic mooring cables and ropes

Abstract

Underwater acoustic experiments at the NATO SACLANT Undersea Research Centre, La Spezia, Italy (SACLANTCEN) are largely dependent on moored and towed instrumentation. Every year up to 500 cable terminations am made and tested in compliance with safety standards to evaluate breaking strength and fatigue effects and life-cycle analysis of fiberropes. Elongation and breaking strength can be determined for rope samples (maximum length 10 meters) subjected to up to 300 kN of tensile force. A computerized acquisition system records the details of safety conhol tests and the associated analysis. The machine also performs tension to tension cycling and "strumming" effect simulations on cable terminations, thus reproducing in air the two basic forcing functions on mooring lines at sea: wave action and current action. Aramid fiber ropes with advanced characteristics a e being evaluated and the apparatus is being applied to the development of a new type of rope with high modulus fibers. An improved, rapidsplicing technique has been developed for reliable cable terminations forlong term moorings. This technique has been successfully applied to the moorings deployed duringAUantic-Ionian-Stream (AIS) 95 and Otranto Gap Experiment (OGEX2) oceanographic experiments in the Sicilian Channel and theAdriatic Sea