The vessel ALSU, measuring 90 meters, is shown in an aerial image near Silivri after colliding with the ship Tuğberk İmamoğlu.
Authorities have detained nine crew members from a commercial ship after a collision with another vessel caused it to sink, with the wreck believed to lie as deep as 900–1,100 meters below the surface.
The collision between the cargo ship Tuğberk İmamoğlu and the tanker Alsu occurred at around 3:15 a.m. on Sept. 2, roughly 18 nautical miles (about 35 kilometers) south of Istanbul’s Silivri, in one of the Sea of Marmara’s busiest shipping corridors.
The Turkish-flagged Alsu, sailing from Kocaeli to Aliağa, collided with the Turkish-flagged Tuğberk İmamoğlu, which was en route from İskenderun to Karadeniz Ereğli.
The Tuğberk İmamoğlu sank within 11 minutes of the collision, and its 10-member crew could not be reached.
The Alsu sustained no visible damage. At the time of the collision, its third officer and an assistant were on duty while the rest of the crew were asleep.
Investigators have recovered the final radio exchange between the two vessels: The Tuğberk İmamoğlu radioed “Alsu, turn to port,” repeating the instruction, to which the Alsu replied “Understood, roger.”
As part of the investigation, nine of the Alsu’s 10 crew members, all except the cook, were questioned as suspects aboard the ship, with detention conditions applied.
Given the ongoing judicial and administrative inquiry, and for the vessel’s security, the suspects were reportedly kept under gendarmerie guard on board. Alcohol tests on the suspects came back negative and blood samples were also taken for further analysis. Prosecutors announced that the nine crew members from the Alsu would be referred to the courthouse.
Search and rescue operations for the missing crew continued through the night in the area, with families and relatives of the crew gathered nearby awaiting news.
Divers are expected to examine the underwater sections of the Alsu. Surface pollution has begun forming in the area where the ship went down, prompting orders for health and environmental monitoring measures.
The sea depth at the point where the Tuğberk İmamoğlu sank is estimated at around 900 meters (other estimates put it between 800 and 1,100 meters), so authorities are working to identify and secure technical equipment capable of operating at that depth in order to gather evidence.
Experts have attributed the ship’s rapid sinking to its cargo of metal material equivalent to the weight of 200 trucks.
Built in 1990, the Tuğberk İmamoğlu was about 90 meters long and 12.8 meters wide. Its last recorded AIS position was received at 7:06 p.m. on Sept. 1, when it was sailing under its own power toward Ereğli.
