Abstract | The capabilities of three on-load release mechanisms were investigated for normal and failure type release operations at the Institute for Ocean Technology. Failures of release mechanisms during maintenance and exercise drills is a well documented occurrence, however, until very recently the possible causes for the failures have only been postulated but never tested in a systematic way. The current study aims at better understanding the operational performance of lifeboat release mechanisms with respect to normal, extreme and failure operational situations. Three twin fall davit on-load release mechanisms were tested in the experimental study. All the release mechanism design types are fully certified by the regulatory bodies. Of the three on-load release mechanisms, two were of older existing design types while the third was of a newer design. Two of the release mechanisms were new and never used outside of this study (one each of older and newer design) and had a loading capacity of 6 tonnes, while the third release mechanisms had been in operation and had a capacity of 3 tonnes. The experiments were conducted in the material testing facility of the Institute for Ocean Technology of the National Research Council of Canada and encompassed the following tests: Inline/offline on-load tests Inline/offline static tests Offline cyclic loading Offline damage release cable Results for the offline on-load tests as well as the offline damage release cable tests will be presented in this report. Thus far all the results from in-line to offline, and from dynamic to static indicate that Hook C appears to have a higher degree of stability than the other two sample hooks. |
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