SSPA was leading a research study on the sinking sequence of MV Estonia between 2006-2008

Goal

The goal was to investigate the sinking sequence and explain the underlying causes of the loss of MV Estonia on 28th September 1994. Improvements regarding future maritime safety of passenger ships were also be recommended in the study. The project, which was financed by VINNOVA (The Swedish Governmental Agency for Innovation Systems), started in March 2006 and was completed in May 2008.

Research Approach

SSPA was leading the investigation and the approach chosen by the SSPA Consortium was:

• To review evidence such as testimonies from survivors and observations from all available video recordings from diving and ROV (Remotely Operated Vehicle) investigations. Four diving team members from the wreck investigation were also interviewed.
• To form an International Panel of Experts (IPE) to assist the SSPA Consortium to suggest different loss hypotheses conformant with the evidence.
• To perform fundamental and systematic model experiments to derive data for numerical simulation models.
• To build comprehensive numerical models to describe the performance of the damaged MV Estonia during the initial foundering phase when it was manoeuvred and when drifting in wind and waves, as well as for the progressive flooding when water enters the ship.
• To evaluate the different loss scenarios and derive the most probable one using different numerical simulation methods.
• To substantiate the most probable scenario by computer simulations/animations and physical model experiments.
• To derive conclusions and to make recommendations for future safety improvements of passenger vessels.

Main Conclusions

The loss of 852 people on the night of 27/28th of September 1994 resulted from a rapid loss of stability by MV Estonia. Therefore, all the circumstances and reasons for - breach of hull integrity allowing unobstructed ingress of sea water into the spaces of MV Estonia - inadequate stability to allow orderly ship evacuation and abandonment in case of such water ingress, were considered as the causes of the disaster.

Most Probable Foundering Scenario

The most probable foundering scenario as identified in the project was:

• The ramp was forced partially open by the bow visor prior to complete visor detachment from the vessel.
• Water was entering the car deck through the openings at the sides of the ramp resulting in a slowly increasing starboard heel angle.
• The ramp remained partially open until the bow visor detached from the hull.
• The ramp fully opened and was crashing down onto the forepeak deck as the visor completely detached from the vessel.
• Large amount of water was entering the car deck resulting in a rapidly growing starboard heel angle up to about 35-40 degrees.
• The ramp may been fluctuating up and down due to the interaction between waves and the pitch motions.
• Water was flooding down to the lower decks through vents and centre casing.
• The officer on the bridge was decreasing the ship speed and started a port turn.
• After turning the ship heel was still increasing and the Main Engines stopped.
• The heel was increasing and the Auxiliary Engines tripped and stopped when the heel angle was more than 45 degrees.
• The ship was now drifting in wind, waves and current and when the heel was about 80-85 degrees the Emergency Generator was shut down.
• The ship capsized.
• The ship sank with bow up.
• The aft part of the ship was hitting the seabed first. The foundering sequence as described was estimated to take about one hour.

The SSPA Consortium

• SSPA Sweden AB, Project Management
• Ship Stability Research Centre/Safety at Sea Ltd, Glasgow, Technical Coordination
• Maritime Research Institute Netherlands (MARIN), Wageningen
• Chalmers University of Technology, Shipping and Marine Technology, Göteborg

All project documentation as well as a video and a computer simulation are available for download:

Project Website

More information is available at the Project Website:

www.safety-at-sea.co.uk/mvestonia/