Failed chain link – catastrophic failures in mooring system
The Bureau of Ocean Energy Management Regulations & Enforcement (BOEMRE) has published Safety Alert No. 296 regarding the catastrophic failure of a chain link in a mooring system, which could have put a floating structure at risk.
In the incident, a single point mooring system failed at the tether chain for a free-standing hybrid riser, allowing the buoyancy air can and the free-standing flow line riser to separate. The 440-ton buoyancy air can rose suddenly to the surface while the free standing riser collapsed.
Further information can be found in the linked IMCA Safety Flash PDF.
Safety Event
Published: 14 July 2011
Download: 
IMCA SF 06/11
IMCA Safety Flashes
Submit a Report
IMCA Safety Flashes summarise key safety matters and incidents, allowing lessons to be more easily learnt for the benefit of all. The effectiveness of the IMCA Safety Flash system depends on Members sharing information and so avoiding repeat incidents. Please consider adding safetyreports@imca-int.com to your internal distribution list for safety alerts or manually submitting information on incidents you consider may be relevant. All information is anonymised or sanitised, as appropriate.
IMCA’s store terms and conditions (https://www.imca-int.com/legal-notices/terms/) apply to all downloads from IMCA’s website, including this document.
IMCA makes every effort to ensure the accuracy and reliability of the data contained in the documents it publishes, but IMCA shall not be liable for any guidance and/or recommendation and/or statement herein contained. The information contained in this document does not fulfil or replace any individual’s or Member's legal, regulatory or other duties or obligations in respect of their operations. Individuals and Members remain solely responsible for the safe, lawful and proper conduct of their operations.