Πέμπτη 2 Μαΐου 2019

Marshall Islands releases report on sinking of Stellar Daisy


More than two years after VLOC Stellar Daisy sank, the Marshall Islands flag has published its report into the tragedy, which killed 22 of the 24 crew on board. The ship's class society Korean Registry quickly issued a response to the report, agreeing with much, disagreeing with some points, and saying that it would act on others.
The Stellar Daisy, owned by South Korea-based Polaris Shipping, sank in the South Atlantic on March 31st 2017  while on a laden voyage from Ilha Guaíba, Brazil, to Qingdao, China. At the time of the sinking she was more than 1,700nm from the coast of Uruguay and 1,800nm from the west coast of South Africa. She sank to a depth of about 3.5km.
The marine safety investigation conducted by the Republic of the Marshall Islands Maritime Administrator determined that the likely direct cause of Stellar Daisy foundering was a rapid list to port following a catastrophic structural failure of the ship’s hull. This caused a loss of buoyancy and uncontrolled flooding.
The structural failure and flooding were 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 ascribed the structural damage to a combination of probable 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 encountered by the vessel between March 29th and 31st.
The Administrator’s marine safety investigation also concluded that the likely causal factors include:
  1. 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 a laden condition;
  2. a gap in the additional safety measures for bulk carriers contained in the International Convention for the Safety of Life at Sea (SOLAS), 1974, Chapter XII, regulation 5. This does not require an assessment to ensure certain types of bulk carrier could withstand the flooding of any one wing tank in all loading and ballast conditions;
  3. ineffective assessments of structural damage identified when the ship was in dry dock in 2011, 2012, and 2015 which failed to determine the cause of the structural damage, identify any potential defects with the conversion design, or require the development of appropriate repair plans.
The Stellar Daisy was formerly a very large crude carrier (VLCC), which completed its conversion to a VLOC in January 2009.
The investigation included interviews with the two surviving crew members, a detailed review of documents related to the ship’s conversion design, maintenance and inspection history, and cargo records, and a third party and Classification Society technical analysis. It also included a review of a video taken during a deep-sea search that was conducted by the Republic of Korea.
The Administrator thanked the marine safety investigation authorities from Korea, the Philippines and from Brazil for the assistance they provided as Substantially Interested States. The Administrator also thanked Polaris Shipping, the Korean Register (KR), and Vale SA for their cooperation.
KR said that in general it agreed with the majority of the content contained within the report and concurred 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 also agreed with the report that the fatigue cracking was probably undetectable by visual inspection prior to the sinking.
KR said that, in its opinion, areas of the report that were "directed specifically at KR which require further explanation".
KR’s areas of concern were focused on page 71 of the report:

Material fatigue
The report stated that KR’s review and approval of the conversion design was based on the assumption that all of the scantlings, including those from when the ship was constructed as a VLCC in 1993, were as original and did not take into account material fatigue. KR responded that "the basis for this assumption was that the Finite Element Analysis (FEA), which was conducted in accordance with the requirements of the KR Rules for Steel Ships, took into consideration allowable stress, corrosion, and stresses due to local notch effect."
KR said that the report correctly stated that the FEA and fatigue strength assessment took into consideration allowable stress, corrosion, and stresses due to local notch effect. It said that this was "common practice for many IACS classification societies. An independent review conducted by Bruce S. Rosenblatt & Associates – the third-party hired by RMI to technically review the conversion process – confirmed that KR’s structural analysis was conducted properly".=
Failure analysis
The report stated that, although KR did conduct a failure analysis of the damage to the transverse bulkhead at frame No 65, it did not conduct a failure analysis after an extensive number of cracks were identified and repaired when the ship was in drydock in 2011, within two years after the conversion was completed. As a result, potential weaknesses with design details were not identified. This is an indication that KR’s monitoring and assessment of the ship’s structural integrity was not as effective as it might have been. KR said that "a failure analysis is carried out at the discretion of the attending surveyor when, in their assessment, a defect or damage is 'out of the ordinary' and further scrutiny is required. This is in accordance with KR procedures and in common with other IACS classification societies. The RMI report correctly states that a failure analysis of the damage to the transverse bulkhead at frame No. 65 was conducted as it was determined by the attending surveyor to be 'out of the ordinary' and similar damage was not found in other parts of the ship. However, the cracks/defects identified and repaired at the time of dry-docking in 2011 were determined to be those typically found on board ships of a 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".

Reporting to Flag Administration
The report stated that KR was authorized to serve as an RO on behalf of the Administrator. The 2016 RO Agreement between the Administrator and KR required that KR immediately inform the Administrator of, among other things, “any dangerous occurrences, accidents, machinery or structural breakdowns, or failures that they are aware of on a Vessel.” KR did not inform the Administrator of the damage to frame No. 65 in 2016. KR responded that, as stated in the casualty investigation report, a failure analysis was carried out to assess the structural integrity of damage to the transverse bulkhead at frame No. 65, the result of which showed that there was no area of concern and proper repairs were undertaken to renew the damaged part to its original condition. KR also examined the surrounding bulkheads of Stellar Daisy as well as bulkheads on 29 other converted VLOCs (approximately 230 bulkheads in total) to determine if there were any similar defects. The result of this extensive investigation was that there were no areas of concern. As a thorough inspection and comprehensive repairs were undertaken, KR determined that there was no “dangerous” structural issue that warranted reporting to the Flag Administration".
However, mindful of the recommendations in the report, KR said that it intended to review its reporting procedures to avoid any future misunderstandings.

Full reports may be read at,




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