ATSB: Cruise Ship's Chief Mate Distracted by ECDIS Ahead of Grounding

Coral Adventurer's grounding location and planned trackline, red (ATSB)

The cruise ship Coral Adventurer ran aground on a reef off Papua New Guinea after the ship's ECDIS declined to load the chief mate's route plan, the first in a series of events that led to the ship overshooting a turn and overcorrecting, according to the Australian Transport Safety Bureau (ATSB).

On the morning of December 27, 2025, Coral Adventurer was under way off the remote northeastern coast of Papua New Guinea and nearing the small port of Dregerhafen. The waters on the approach are ringed by reefs, with large areas poorly surveyed, and vessels have to execute two tight turns to reach the harbor entrance - first to port, then to starboard.

At the start of the 0400 watch, the cruise ship was approaching Dregerhafen's harbor entrance. The chief mate had the conn, and decided to adjust the route in the ECDIS to smooth out the second of the two turns of the transit, thereby creating a new route plan in the digital chart system's storage. The new Route 2 still adhered closely to the passage plan's track, but with an extra waypoint.

At 0512, as the approach to the port was in progress, the mate selected this modified route and tried to activate it. The ECDIS declined to do so until after it had performed a route safety check in its route editor tool.

The chief mate had to go through the process of this digital check mid-transit. At 01513, the Coral Adventurer missed its first wheel over point and overshot its turn to port. This put it on course to enter unsurveyed and potentially hazardous waters to the north of the route. The chief mate put steering in manual and made a harder turn to get back onto the route. The vessel returned to the planned track, but slowed down, affected by a strong current at the entrance channel.

The chief mate increased RPM on both thrusters to offset the current, which had reduced speed to less than four knots. With the throttes pushed up, the mate put steering back into autopilot at about 0518, in advance of the second turn. At 0519, the vessel arrived at the second wheel over point, making eight knots. The vessel overshot the turn again, prompting the mate to switch back to manual once more at 0521. The ship was off course to the west of the intended trackline, and the mate made a hard turn to starboard to get onto the planned track.

At this point, the chief mate lost situational awareness, they later told investigators. In darkness and without navigation aids, they did not have a sense of the surrounding topography. The mate kept up the high rate of turn to starboard until 0523:30, coming up on a northeasterly heading back towards the trackline. Misinterpreting the view ahead and believing that the ship was back on track, the mate continued to navigate across the trackline, making more than eight knots.

At 0524, the master arrived on the bridge, and visually spotted shallow water ahead; the ship grounded about 15 seconds after the master's warning. The Coral Adventurer came from 8.5 knots to a halt by 0525:30.

Dive inspections revealed that the hull was not penetrated, and that the propulsion was intact. A tug was chartered for a refloat attempt, but this was initially unsuccessful, as the tug's engines overheated during the effort. A larger tug was dispatched, and the Coral Adventurer was successfully refloated on December 30.

Wednesday's report is a factfinding summary, without causal findings. ATSB's inquiry into the cause of the grounding remains under way.