The incident

On 31 March 2017, the 266,141 dwt, very large ore carrier (VLOC) Stellar Daisy was underway in South Atlantic ocean, on its way from Brazil to Qingdao, China, when it sank about 1,700 off Uruguay. The water depth in the area was approximately 3,400-3,600 m. Of the 24 crew members onboard, two were rescued. The other 22 crew members are missing and presumed dead.

Probable causes

The 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 that resulted in a loss of buoyancy and uncontrolled flooding.

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 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 10 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.

Conclusions

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 SOLAS, 1974, Chapter XII, regulation 5 which does not require an assessment to ensure bulk carriers of 150 m or more in length of double-side skin construction, designed to carry solid bulk cargoes with a density of 1,000 kilograms per cubic meter (kg/m3) and above, constructed on or after 1 July 2006 with any part of the longitudinal bulkhead located within B/5 or 11.5 m, whichever is less, inboard from the ship’s side at a right angle to the centerline at the assigned summer load line can 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.

Potential contributing factors include:

  1. Inconsistent compliance of the owner with both KR’s requirements for reporting structural defects and the Administrator’s requirements for reporting marine incidents and marine casualties;
  2. Ineffective enforcement of the Classification Society’s rules to ensure the owner was reporting identified damage;
  3. Non-compliance by KR with the requirements in the 2016 RO Agreement to notify the Administrator of, among other things, “any dangerous occurrences, accidents, machinery or structural breakdowns, or failures that they are aware of on a Vessel;”181 and
  4. The less stringent requirements of the 2011 ESP Code regarding the schedule of annual inspections of WBTs on bulk carriers due to deterioration of coatings when compared to those for WBTs on tankers.

Further details may be found herebelow: