Stage

• On Scene
• Factual Collection
• Analysis
• Final Draft
• Closure

At 1342 hours (local time) on May 14, 2025, the Taiwan-flagged container vessel Uni-Active (IMO No. 9130547, gross tonnage 14807, length overall 165.00 meters, beam 27.10 meters, container capacity 1,296 TEU), while conducting a turning maneuver during departure within the Yangon River channel, Myanmar, had its stern collide with three vessels moored abreast at the pier. As a result of the occurrence, Navy 217 and Dana Hlaing sank, and Annawar Aung 8 sustained hull damage, but no injuries or pollution were reported.

Conclusions

Findings Related to Probable Causes
• 1. During the outbound turning maneuver in the restricted waters of the Yangon River anchorage, Uni-Active was operated astern without personnel assigned to monitor the stern movement. The pilot and the master focused primarily on the distance between the bow and the riverbank, while the bridge team did not effectively integrate radar and other navigational monitoring information to maintain overall situational awareness of the vessel’s movement. As a result, the increasing sternway inertia was not identified in a timely manner, and the vessel’s stern collided with small vessels moored alongside the berth at a speed of approximately 3.3 knots astern, resulting in the sinking of two vessels and damage to a third vessel.

Findings Related to Risk
• 1. Prior to commencing the turning maneuver, the pilot and the master did not conduct a sufficient Master–Pilot Information Exchange (MPX) in accordance with the recommendations of IMO A.960(23). No agreed turning plan or shared understanding was established regarding maneuver intentions, such as speed control and clearance distances, nor were contingency actions discussed. This limited the bridge team’s ability to take timely control in response to emerging risks.
  2. Although the master became aware that the pilot’s selected turning method in the restricted waters differed from previous practice, the associated risks related to vessel speed, position, and passing distances during the turning maneuver were not discussed with the pilot. In addition, the bridge team did not establish clear monitoring priorities or task allocation to support effective risk oversight during the operation.
  3. During the operation of weighing anchor and conducting a turning maneuver in restricted waters, the vessel did not treat the risk of stern movement astern as a primary monitoring focus. Throughout the operation, no real-time identification and response measures were established based on changes in vessel speed, position, or the relative distance of the stern. As a result, this risk was not timely identified or addressed in operational decision-making, thereby increasing the risk of collision during turning operations within the river channel.

Other Findings
• 1. Steering gear and main engine were operating normally at the time of the occurrence.
  2. At the time of the occurrence, the vessel’s Global Positioning System (GPS), Automatic Identification System (AIS), and Electronic Chart Display and Information System (ECDIS) experienced brief signal instability, which was a commonly reported condition in this river section.
  3. At the time of the occurrence, weather conditions were good, with a south-easterly wind at Beaufort scale force 2 and good visibility.
  4. The master and on-watch crew of the vessel held valid certificates of competency issued by the competent authority of Taiwan. The pilot held a valid pilot licence issued by the competent maritime authority of Myanmar. No evidence of fatigue was identified.