Lifeboat Release Mechanism Tests

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TypeTechnical Report
Series titleTechnical Report; no. TR-2009-23
Subjecton-load; off-load; twin fall davit; release mechanisms
AbstractThe capabilities of three on-load and one off-load release mechanisms were investigated for normal, extreme and failure type release operations at the Institute for Ocean Technology. The failure of release mechanisms during maintenance and exercise drills is a well-documented occurrence. However, until very recently the possible causes of the failures have only been postulated but never tested in a systematic way. The current study aims for a better understanding of the operational performance of lifeboat release mechanisms with respect to normal, extreme and failure operational situations. Three twin fall davit on-load release mechanisms and one off-load release mechanism 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 (next generation) design. Of the four release mechanisms tested, two of the mechanisms were new and never used outside of this study. Also, one of the never used new mechanisms was of an older design while the other was the next generation design. The never used mechanisms had a loading capacity of 6 tonnes, while the third on-load release mechanism had been in operation for some time and had a capacity of 3 tonnes. The off-load mechanism had also been in use and had a capacity of 12 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 Inline off-load tests Results for the above mentioned 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, the next generation design, appears to have a higher degree of stability than the other two sample hooks. The off-load release mechanism was limited to inline tests and followed a different testing procedure as the on-load mechanisms. The off-load release mechanism worked as intended in the limited test conditions.
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AffiliationNRC Institute for Ocean Technology; National Research Council Canada
Peer reviewedNo
NPARC number18227294
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Record identifier86c28b75-0af4-4728-85f1-5ff831781af3
Record created2011-07-07
Record modified2016-10-03
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