The investigation by Indonesia's National Transportation Safety Committee revealed a catastrophic design failure. The ferry's superstructure -- the enclosed passenger area above the main deck -- was built with fiberglass-reinforced plastic just four millimeters thick at the front wall. Eight fiber layers, reinforced with blocks that investigators later calculated were insufficient to maintain structural integrity. Worse, the ratio of catalyst to resin in the fiberglass was inverted: too much catalyst had made the composite brittle rather than flexible. At 26 knots, driving directly into heavy seas, the force of the waves was powerful enough to tear through this wall. One eyewitness described the impact knocking a television off the wall inside the passenger cabin. Cracks opened near the bridge, and the sea poured in.

What happened next was a cascade of engineering oversights. The forecastle deck was an open design surrounded by bulwark, which meant water that crashed over the bow had no way to drain back into the sea -- it was trapped on deck. As waves continued to batter the cracked front wall, water flooded through the breach and leaked down the air conditioning shaft into the main passenger area. From there, it reached a non-weatherproof access port and drained into the cargo compartment below. The main deck flooded, the ferry lost buoyancy through what investigators called the free surface effect, and the bow began to sink. The vessel listed to port. Passengers, receiving no instructions from the crew, began smashing windows and jumping into the sea on their own initiative.

Survivors described a crew that was overwhelmed and untrained. No damage control was attempted. No distress signal was issued. Investigators later found that the captain, despite having enough experience to recognize dangerous weather conditions, had continued the journey to Dumai rather than turning back. Crew response was uncoordinated, crowd control failed, and panic spread unchecked through the passenger areas. On shore, confusion mirrored the chaos at sea. The passenger manifest listed 228 people aboard, but the ferry's capacity was 273, and a health official estimated 291 were actually on board. Ticketless passengers made an accurate count impossible. The house of Karimun Regency's regent, Nurdin Basirun, was pressed into service as both a temporary shelter for survivors and a crisis center.

Rescue operations began immediately but were hampered by the same violent weather that had sunk the ferry. Fishing boats and other ferries joined the effort first. By the evening of November 22, rescue teams had pulled 261 survivors from the water but recovered 18 bodies, including two infants. The next day, the toll rose to 30 dead with dozens still missing. Over the following days, the Indonesian Navy, customs vessels, and 21 ships including four military vessels joined the search. Rough waves damaged the propeller of one rescue ship. The wreckage was eventually located at a depth of 40 meters, two kilometers from the sinking site. Divers recovered two more bodies from inside the hull, bringing the confirmed dead to 42. Thirty-three people remained listed as missing -- presumed drowned in waters that never calmed enough to allow a thorough search.

The Dumai Express 10 was Indonesia's second major ferry disaster that year. Months earlier, a ferry capsized in bad weather off Majene, West Sulawesi, killing more than 300 people. Indonesia's archipelago geography makes ferry travel essential for millions, but the industry has long been plagued by overcrowding, inadequate safety regulation, and poor maintenance oversight. Investigators found that PT. Lestari Indomas Bahari had insufficiently supervised its crew and failed to implement proper safety monitoring. The crew lacked adequate emergency training, partly due to high roster turnover. Relatives of the victims petitioned authorities to raise the wreckage. The ferry that Boheng owned -- the same Boheng who gave away his lifejacket in the final minutes -- remained on the seafloor, a 40-meter-deep marker of systemic failures that no single act of personal courage could overcome.