The ship sank on September 28, 1994, with the loss of 852 lives, as a result of being unseaworthy, the report's preliminary assessment has found.

Damage to the Estonia's hull uncovered by wreck dives in recent years and which sparked various conspiracy theories on the causes of the disaster, was the result of contact with the seabed when the sinking vessel hit ground, the report added.

The geology of the area where the ship sank, in around 100 meters of water south of Finland's Turku archipelago, includes rocky outcrops that both damaged the hull initially and contributed to the movement of the wreck as it settled. Additionally, damage due mainly to erosion has occurred in the three decades since the disaster.

The 2020 footage filmed for a documentary on the MS Estonia, which revealed the damage, did prompt a new official investigation by authorities in Estonia, Finland, and Sweden, however.

All three authorities — the Estonian Safety Investigation Centre (OJK), the Swedish Accident Investigation Authority (SHK), and the Finnish Safety Investigation Authority (OTKES) — found no need to reopen the accident investigation.

"Our work has also provided a thorough and up-to-date overview of the condition of the wreck, the sequence of events, and the broader systemic factors that caused the accident," OJK Director Märt Ots said.

The report's authors presented several conclusions based on marine surveys, interviews with survivors, technical expert assessments, plus scientific calculations and computational modeling.

"We have worked with experts from many different fields and conducted six investigations at the wreck site. The seabed at the wreck location is very well documented. The midships section of the vessel rests on a 1.8-billion-year-old gneiss outcrop – a rigid basement rock formation that runs almost diagonally beneath the wreck. The fact that the wreck lies on a slope explains the significant movement of the wreck over the years," said SHK Director of Investigations Jonas Bäckstrand.

The wreck is severely damaged and has shifted considerably on the seabed over the decades, he noted. The shape of the damage on the starboard side is congruous with that of the nearby exposed sediment rock. The condition of the wreck continues to deteriorate over time, making the formation of new deformations viable too.

Work to cover the wreck, mostly in aggregate, has also played a part.

"Although the wreck-covering works carried out in the mid-1990s have been heavily criticized, the archived documents from those studies have proven to be valuable evidence for the preliminary assessment. Based on these documents, we were able to reconstruct changes in the wreck's location and position on the seabed. This explains why the previously unknown starboard-side damage was not visible in the 1990s but was revealed later due to the movement of the wreck," OJK lead investigator Tauri Roosipu added.

Plans to fully encase the wreck in concrete did not materialize.

Undetected structural deficiencies: No collisions or explosions

Beyond that, there has been no indication of any collision with another vessel or object while the ship was still afloat, nor are there any signs of any explosion on the starboard side or in the bow area or anywhere else. These have both formed the basis of alternative explanations for the disaster.

The examination of the bow ramp raised from the seabed in 2023 and the computational modeling of the failure of the bow structure are consistent with the conclusions of the 1997 Joint Accident Investigation Commission of Estonia, Finland, and Sweden (JAIC). This found that the bow visor failed due to wave overload. The bow ramp then opened, and water began to flow onto the car deck.

Updated computational modeling also supports the accepted explanation: Rapid water ingress through the bow ramp ultimately led to the capsizing of the vessel. Alternative scenarios, including water ingress through a rupture or other opening on the starboard side, are not consistent with calculations, witness statements, or other collected evidence, the report found.

According to the OJK and SHK joint assessment, the MS Estonia was not seaworthy as it had undetected structural deficiencies, due to a lack of inspection, as well as exemptions from rules that were not reflected in the certification.

"The vessel had hidden structural deficiencies throughout its entire service life and was technically not safe to operate on that route. The relevant parties were not aware of this – neither on board the vessel nor ashore," Bäckstrand added.

"The interviews denote that a certain amount of water moved from the car deck into the cabin areas below. They also confirm that military vehicles were not loaded onto the vessel. Many witnesses expressed opposition to the idea of covering the wreck and did not understand why the bodies of the victims were not recovered," SHK lead investigator Jörgen Zachau added.

A complex systemic failure

"The final report emphasizes that the sinking of the ferry Estonia was not caused by a single root cause or by the individual actions of the crew. It was a complex systemic failure within the shipping sector, involving numerous shortcomings. This accident was regrettably a wake-up call for the entire sector, as incidents involving bow visors had occurred even before the accident, but knowledge of them was not widespread within the industry," Roosipuu said.

This dated back even to the Estonia, laid down in 1979 and originally sailing as the Viking Sally, being on the drawing board, he noted.

The chain of errors that started with an inadequate regulatory framework continued through the vessel's design and construction phases, exacerbated by insufficient oversight and deviations in certification, together with poor working practices and safety culture in the maritime sector.

All these factors served to create a situation that made the disaster near impossible to prevent once the first failures emerged.

The final report also notes that public discussion has often focused on individual factors, such as the vessel's speed or maintenance quality, rather than looking at things holistically.

The preliminary assessment outlines that these factors alone, while important, are not sufficient to explain the sinking; the catastrophe was the result of an accumulation of systemic failures and inadequate risk management across the entire sector.

Lessons learned

One positive that did emerge from the tragedy was the development and implementation of new harmonized regulations, particularly concerning bow structures and vessel stability, the strengthening of existing ships, and the development of rescue tech.

The more than three decades of safe ferry traffic in the North Sea and Baltic Sea region since the accident demonstrate valuable lessons were learned from the disaster, improving maritime safety.

Taking all available evidence into account, it can be concluded that the MS Estonia sank due to the failure of the bow structure, while the new starboard-side damage resulted from contact with the seabed. There is therefore no need to reopen the safety investigation into the accident, the report found.

The Estonia disaster is the second deadliest peacetime maritime disaster after the April 1912 sinking of the Titanic.

In March 1987, bow door issues led to the disaster involving the Herald of Free Enterprise passenger ferry as it left Zeebrugge harbor in Belgium, destined for the U.K. This was the direct result of human error, as the vehicle deck doors were left in the open position. Despite this happening in shallow waters and the ferry capsizing rather than sinking, the death toll reached 193.

The preliminary assessment of the final report on the Estonia passenger ferry disaster is to be presented on Tuesday afternoon. ERR News is live-streaming the press conference from 3 p.m. Estonian time.

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