Eyewitnesses reported that massive waves had struck the ferry repeatedly, causing the starboard side of the ship to crack.

Earlier in the year, a ferry carrying more than 300 people capsized during bad weather in Majene, West Sulawesi, and more than 300 were killed in the disaster.

The investigation revealed that the superstructure's front wall of the ferry was insufficient to counter-act the force of the waves.

Several minutes later, after it had passed Nipah Island, the weather deteriorated and the waves became higher, with an estimated height of 2.5–4 metres (8.2–13.1 ft).

A crew member ordered by the captain to check the origin of the sound, spotted a crack on the front wall and water had rushed into the passenger area.

[3] Huge waves struck the ferry repeatedly from the front, causing large quantity of water to enter the passenger area.

As the ferry sank further, eyewitness stated that the crack on the wall burst and a large amount of water immediately rushed to the passenger area.

Most people rushed to the ferry's stern (the back), which was raised due to the sinking of the bow.

According to survivors, several people on the front part of the lower deck were unable to escape due to the angle of the list and the large amount of water.

Several passengers smashed the side windows to escape while others immediately jumped into the water although the crew never finished inflating the lifeboats.

Indonesian National Search and Rescue Agency immediately deployed 5 patrol ships to the area.

[8] On 23 November, Indonesian National Search and Rescue Agency reported that 30 people were killed[9] and dozens were listed as missing.

The house of the regent of Karimun Regency Nurdin Basirun was used as a temporary shelter for the survivors and as a crisis centre.

They asked rescuers to find the wreckage of the sunken ferry and search for more bodies, as they believed that most of the missing were trapped inside.

[3] On 2 December, at 16:00 local time, the wreckage of the ferry was located by KRI Pulau Romang, an Indonesian military ship.

[23] An Indonesian health official indicated that the ship was carrying 291 people; although the ferry had a capacity of 273, overloading is common.

[24] Captain Johan Napitupulu denied that the ferry was overcrowded and indicated that they had no warning of a storm at the time of departure.

Members of the NTSC added that the case of the sinking might be handed over to the Indonesian Court of Shipping.

[3] Multiple witnesses stated that water entered the passenger area through cracks that had been formed by the strong rough waves.

The flooding of the main deck caused the ferry to lose its ability to float due to free surface effect.

Calculation conducted by investigators revealed that the blocks were insufficient to hold the structural integrity of the superstructure.

Eyewitness confirmed that the force was so strong that a television, which was placed behind the wall, fell to the floor due to the impact.

Inspection on the wreckage showed that the catalyst on the fiber was higher than the amount of resin, confirming the investigators that the 4 mm thick front wall was easily breakable.

The water then leaked into the air conditioning shaft, flooding the front portion of the main passenger area.

Investigators noted that the captain was experienced enough to recognize that the weather at the time was unsuitable for a ferry to operate.

[3] Testimonies collected from survivors revealed that crew response was uncoordinated resulting in poor crowd control and uncontained panic.

The crew insufficiently understand the emergency procedure due to their high roster time.