CHAPTER 34

SEPARATE INVESTIGATIONS

In the course of the year 1995 and subsequently this 'Group of Experts' initiated a number of technical and scientific investigations to ascertain the load exposure of the visor and its locking devices, the actual strength of the Atlantic Lock and the condition of parts recovered from wreck and visor. Also the break load of the bow ramp hinges and the forces necessary for the visor lugs to cut through the deck beam at frame 159 were calculated. In addition the available video footage was evaluated and analysed and the videos still showing unexplainable damage to the wreck were examined by a diving and explosive expert. Furthermore the investigation results of "The Independent Fact Group", Stockholm, concerning the forgery of documents to hide the initial unseaworthi-ness of the ESTONIA have been taken up into this chapter with the permission of the authors. Finally, the results of an investigation by the Det Norske Veritas Classification A/S Håvik/Norway concerning the design load aspects for the bow area of Ro-Ro vessels under the heading "Bow Impact of Ro-Ro Vessels" have been made available and shall be considered in this chapter as well.
In detail:

 

 

34.1
Forgery of Documents to hide the initial Unseaworthiness
of the "Estonia" by The Independent Fact Group, Stockholm (IFG)

This group consists of Björn Stenberg, Johan Ridderstolpe and a number of unknown members, preferring to stay in the background. It was founded in the beginning of 1999 to clarify, in a well structured and methodical way, the many open questions and speculations in connection with the ESTONIA catastrophe, the work of the JAIC and behaviour of the Government.
It is the purpose to enable the political decision makers on basis of facts to reconsider the matter and, finally, agree on a new investigation.
The first work of the IFG concerns the very carefully performed analyses of different documents found in the archives of the JAIC and Shipinspec in Stockholm. These documents relate to the inspection of the ESTONIA until about 2 hours before her last departure by The Swedish inspectors Åke Sjöblom and Gunnar Zahlée from the Shipinspec Malmö office. The inspection was meant to be a Port State Control (PSC) to train 8 or 9 high ranking Estonian officials. - See Chapter 15. At the end the normal PSC form used by Shipinspec inspectors in Swedish ports was filled out and the "findings" entered. Both form and findings do exist in at least 4, probably 5, different versions, all of which are discussed and evaluated by the IFG, the apparent purpose being to hide in hindsight the initial unseaworthiness of the ESTONIA upon departure from Tallinn which would clearly have been established if the complete findings would have been entered into the form as required.
The complete IFG Report in the Swedish original and in German translation is attached as Enclosures 34.1.429 and 34.1.429.1.

 

34.2
Structural Analysis of Bow Visor and Locking Devices
by means of the Finite Element Analysis by the Technical University Hamburg-Harburg

As part of the investigation in connection with the sinking of the ferry ESTONIA the structure of the visor has been calculated on the basis of the load requirements by the Classification Society Bureau Veritas (B.V.) by means of the Finite Element Method. Thereby the distribution of the reaction forces on the fixing points of the visor, and especially on the Atlantic lock, were of particular interest because of the allegations published by the JAIC that the casualty had been initiated by the failure of the locking devices of the visor. For this reason detailed calculations have been performed, including cases whereby only a limited attachment still existed after the hinges had failed.
At the time of the design and construction of the vessel in 1979/1980 such detailed calculations were neither required by the Classification Societies nor were they state-of-the-art. The selected load on the model is based on an analysis of B.V. whereby the load, acting normally on the shell plating of the visor was assumed to be the water pressure acting on the visor when the ferry was underway. The load acting on the lowest part of the visor was assumed to be 7 t/m² and decreasing continuously with increasing height. At no height level is the pressure less than 3.5 t/m². The load includes the C-deck (forecastle deck).
The weight of the empty visor and the rubber packings on the forepeak deck have been taken into account in all calculations. Wave loads have been assumed to act only on the port side of the visor.

Before discussing the results, the symbols for the directions into which the forces were acting shall be explained:

x = transverse (athwartship)
y = longitudinal (forward aft)
z = vertical

The calculations clearly reveal that as long as the hinges are intact the Atlantic lock takes only very little load. The force direction is opposite to the direction into which the vessel is proceeding, i.e. aft. The small load is to be attributed to the low stiffeners and the high deformation of the visor bottom. Even by using a more detailed net of finite elements no other tendencies became apparent respectively no other results were achieved.
In normal cases the highest loads appear in way of the side locks. The loads cause the aft bulkheads of the visor to be pressed against the front bulkheads of the vessel in the middle and upper areas.
In case also the rubber packing of the visor on the vessel's front bulkheads are taken into account the vertically acting loads are reduced.
If a load is acting on the visor only from one side the hinge on this side has to bear excessive load while the load on the other is less than normal, however, partly acting from different directions.
In case the visor is under constant pressure the loads on the hinges and side locks do increase while the load on the Atlantic lock is decreasing. In case one or both hinges fail all other fixing points have to bear substantially more load and the force direction on the Atlantic lock changes to the opposite direction, i.e. to forward.
In case one hinge fails the Atlantic lock has to bear 2.6 times of the normal load, if both hinges fail the Atlantic lock has to bear 15.8 times of the normal load.
The results of this structural analysis of the visor can be summarised as follows:

By means of several calculation models various load conditions have been simulated, for example the pressure load according to B.V., the load from the side and the load due to a permanent pressure load. In all cases the visor's own weight was taken into account.
The different fixing point conditions were simulated as follows:

- visor fixed to hinges and locking devices,
- additionally the rubber packings were considered,
- additionally considering the manual side locks,
- failure of one and both hinges. The analysis reveals that the Atlantic lock absorbs only a small force component as long as the hinges are intact. The force direction is aft.

The highest forces on the fixing points are effective when the load is acting simultaneously on both side locks. If the visor is exposed to a load only on one side, the load on the hinges on this side is the biggest.
In case that one or both hinges fail, the Atlantic lock becomes exposed to very heavy loads and the force direction changes by 180° to forward.
If both hinges fail the Atlantic lock has to take the heaviest load. The complete Report is attached as Enclosure 34.2.430.