The report said the very large ore carrier, which sank in March 2017 with 22 crew members presumed deceased, suffered “catastrophic structural failure” to the ship’s hull.
The Stellar Daisy, a very large ore carrier (VLOC) that sank in March 2017 in the South Atlantic Ocean, suffered “catastrophic structural failure to the ship’s hull that resulted in a loss of buoyancy and uncontrolled flooding,” according to the casualty investigation report by flag-state Marshall Islands’ maritime administrator.
The ship, which was converted from a very large crude carrier in China in 2008 and was operated by Polaris Shipping Co. Ltd. since 2009, sank on a laden voyage from Ilha Guaiba, Brazil, to Qingdao, China, more than 1,700 nautical miles from the coast of Uruguay and 1,800 nautical miles off the west coast of South Africa. Twenty-two of the 24 crew members on board are missing and presumed deceased.
“The structural failure and flooding are thought to have begun in the No. 2 port water ballast tank (WBT) and then progressed rapidly to include structural failure and flooding in multiple WBTs, voids and cargo holds,” the report reads. “The structural damage was likely due to a combination of factors, including the strength of the ship’s structure being compromised over time due to material fatigue, corrosion, unidentified structural defects, multi-port loading and the forces imposed on the hull as a result of the weather conditions Stellar Daisy encountered between 29-31 March 2017.”
The administrator’s marine safety investigation found three factors that likely caused the incident. The report said the large port and starboard wing tanks “increased the potential for a major structural failure and loss of buoyancy in the event that one or more of these tanks flooded while the ship was in laden condition;” a gap in the safety measures for bulk carriers in the International Convention for the Safety of Life at Sea regulation; and ineffective assessments of structural damage identified when the ship was in dry dock in 2011, 2012 and 2015 were all likely causal factors.
Korean Register, the 266,141 deadweight ton ship’s Recognized Organization, responded Monday to the report.
“In general, KR agrees with the majority of the content contained within the report and concurs that the most likely explanation for the loss of the vessel was due to a catastrophic structural failure of the ship’s hull which probably began in No. 2 Port Water Ballast Tank (WBT),” KR said. “The structural failure was most likely a result of a combination of factors, including the strength of the ship’s structure being compromised over time due to material fatigue, corrosion, unidentified structural defects, multi-port loading and the forces imposed on the hull as a result of conditions Stellar Daisy encountered between 29-31 March 2017. KR agrees with the report … that the fatigue cracking was probably undetectable by visual inspection prior to the sinking.”
KR said an independent review conducted by Bruce S. Rosenblatt & Associates, which was hired by the Marshall Islands, confirmed KR’s structural analysis was conducted properly. It also said the cracks and defects identified and repaired in 2011 were those typically found on board of ships of similar age.
“Based on this observation, the attending surveyor determined that the cracks/defects were not ‘out of the ordinary’ and as long as proper repairs were performed, a failure analysis was not needed,” KR said.
KR also plans to review its reporting procedures to avoid future misunderstandings after the report stated KR did not inform the administrator of damage to the ship’s frame No. 65 in 2016.