Two crews not maintaining proper lookouts led to the collision between a yacht and a tank vessel near Nassau, Bahamas, on December 23, 2021, the National Transportation Safety Board (NTSB) said earlier this week.
The collision resulted in the sinking of the Belize-registered product tanker Tropic Breeze and nearly US$7.9 million in damages.
The motor yacht Utopia IV and Tropic Breeze were transiting the Northeast Providence Channel on the said date when the two vessels collided. The tanker's engine room flooded, and the vessel eventually sank.
The tanker's seven crewmembers abandoned ship and were rescued by a Good Samaritan vessel. Three of the 12 crewmembers on the yacht were injured.
Before the collision, the captain of Utopia IV was conning the vessel while the bosun navigated and kept a bridge log. On Tropic Breeze, the master and an able seafarer were on watch on the bridge.
The captain of Utopia IV left the bridge shortly before the collision to check on the seven yacht passengers. The bosun, who was not credentialed as a watch officer and was not allowed by regulations to conn the vessel alone, was left performing watchstanding duties by himself and logging navigational data.
At 22:00 local time, the bow of Utopia IV, traveling at about 20 knots, struck the transom of Tropic Breeze from directly astern.
None of the watchstanders on Utopia IV or Tropic Breeze reported seeing the other vessel on radar. According to the report, it is likely none of the watchstanders had looked at the radar in the 12 minutes before the collision.
During the voyage, Tropic Breeze's automatic identification system (AIS) was inoperative due to a power issue. If the unit was working, Utopia IV's watchstander could have detected Tropic Breeze before the collision and Tropic Breeze's system would have been able to identify the yacht's position as it approached from astern.
NTSB investigators concluded that if either vessel had kept a proper lookout, they likely would have detected each other and could have taken action to avoid the collision.
The NTSB determined the probable cause of the collision was Utopia IV's wheelhouse crew not maintaining a proper lookout and therefore not identifying the tank vessel they were overtaking. Contributing was Tropic Breeze's bridge team also not maintaining a proper lookout.
"A proper lookout by suitably trained crewmembers is required by the Convention on the International Regulations for Preventing Collisions at Sea, 1972 and is essential in determining the risk of collision," the report said. "The effective use of all available resources by a bridge team, including visual scanning, radars, electronic charts, and an automatic identification system, increases collective situational awareness and contributes to a safe navigation watch.
"Operators and crews should ensure that vessel bridge teams are staffed with certificated/credentialed mariners who are familiar with all bridge navigation equipment and able to independently take immediate action."