Read also the book Disasterinvestigation
Chapter 3 Technical Descriptions of Visor, Ramp and Damages
3.5 The Control Panel
The panel for visor and ramp operation and control was located at port side inside the ramp on the car deck. During closing operations you evidently had to close the ramp first as outlined above and then you had to close and lock the visor.
The normal vertical load acting on the visor is, as described in 3.2, a function of the visor volume and weight. You would expect the maximum load to be about 165 tonnes of buoyancy minus 55 tonnes of weight, i.e. 110 tonnes to which you could add, say 30%, to account for dynamic effects and the fact that the visor might be submerged below its upper part. The total vertical upwards load on the visor would then be P = 143 tonnes when the ship puts the bow into a wave up to the top of the focsle. This load should then be transmitted to the hull via the three locks - 1.25P = 179 tonnes (horizontally) via the Atlantic lock (tension in the visor lug) and 0.265P = 90 tonnes via each side lock (compression in the visor lugs). No load should have been transmitted via the deck hinges (as there should have been a positive clearance between the visor hinge bush and pin). See figure 3.2.
Model tests carried out by the JAIC generally confirms the magnitude of the vertical load acting on the visor. However, transient (shorter life = milliseconds) loads of higher magnitude - slamming - were also recorded. The slamming load was always perpendicular to the visor side and its sideways and longitudinal components were of course transmitted to the hull via the horns/pockets and the vertical contact points. The vertical component of the slamming load was naturally transmitted to the hull only via the locks.
Note August 2000 - read the analysis of the JAIC model test report.
The JAIC alleges that a high amplitude, transient impact load (360 tonnes 4.12) on the visor first ripped apart the Atlantic lock at about 01.00. There is no proof for this. Nobody heard (a) the impact itself or (b) that the visor lock was ripped apart. The energy of the impact should have been noticed as a shock wave aboard the ship (unless this was event 1 in 2.2 - 20 minutes earlier).
The Atlantic lock was damaged as follows:-
The two longitudinal hull lugs supporting the port pin bushing had been torn apart in the 8 and 2 o'clock positions. The port bush had been torn away from the remains of the lugs and was missing. The longitudinal hull lug supporting the starboard pin bush had likewise been torn apart. It should be noted that the starboard bush was also connected by welding to the hull by a transverse bracket and that the bush had been torn away from the transverse bracket
The locking pin was found connected to the hydraulic piston rod, which was in the pushed out position, and which had been bent upwards and sideways to port.
3.8 The JAIC Damage Allegations - the Side Locks
Immediately after the Atlantic lock fails as alleged by JAIC, the load transmission between visor and hull changes. A vertical load on the visor should now only be transmitted via the side locks and via the deck hinges.
Regardless, it should be clear that the Atlantic lock could not have been damaged by the same wave (load) as the side locks. First the Atlantic locks must fail by one very large impact, after which the load transmission pattern is modified, and then the side locks must fail by another very large impact. If one big impact was followed by another big impact, then of course all three lock could have been ripped apart within 10-12 seconds, but it could also be a longer time between the big waves. Nobody heard the second impact against the ship and that the side locks were ripped apart.
After the alleged side locks failure, the visor was only held in place by the deck hinges. However, the visor lifting arms were connected to the hydraulic lifting pistons and it is now assumed that the pistons restrained the motion of the visor. If the visor had not been restrained by the hydraulic pistons, a vertical wave load with enough energy exceeding the visor potential energy would of course had swung the visor around the hinge points, and the visor would have ended up upside down on the focsle deck in front of the deck house! This did not happen.
The JAIC alleges that the visor was now flipping up and down around the hinge points, when big vertical wave loads acted on the visor, and that there were heavy noises. The JAIC writes (on page 175 in (13)) that:
'it is beyond doubt that the sounds were caused by the visor moving and pounding on the forepeak deck'.
3.10 The JAIC Damage Allegations - the Inner Ramp
The JAIC allegation is not supported by any facts or findings anywhere. If the visor ramp recess had dislodged the ramp from its locks, you would expect the recess to be damaged, but only some stiffeners on the port side are bent a little - the plate is straight and the aft, lower edge of the recess is straight and undamaged.
Furthermore, the ramp hooks have not been salvaged and brought to the surface and to a laboratory for investigation. The JAIC states that the hooks were locked before the accident 1.15.5, so you would expect that they had been broken, but there is no proof for this. JAIC has also stated that the four side locks were engaged before the accident, but it is not clear how and when they were damaged, e.g. dislodged by the visor pushing on the ramp top.
The longitudinal load pushing the ramp forward should have been of the order 10 tonnes (0.10 MN) 4.23 (to counter the moment trying to tip the visor forward) but probably less as the visor was kept in place also by the bulkhead at fr. 159. As there were six connection points between the ramp and the hull - two hooks and four locking pins/bolts the average load on the lock was only 3-4 tonnes. Evidently the visor resting on the ramp top could not have ripped apart the hooks or the pins/bolts. So what actually happened?
3.14 The actual Condition of the Visor
According to the Commission (13) the visor was in excellent and original condition without any modifications done to it during 15 years and without wear and tear. According to the German Group of Experts (11) the visor was not maintained properly. The Final Report does not mention the following.
The rubber packings were not renewed when worn and the visor was not weathertight. Also the pre-tension function of the rubber packings was lost, and this had the effect that the visor was vibrating/shaking at sea within the play of the three locks. The German Group of Experts did not point out clearly that this meant that the load transmission between visor and hull was modified and that more load was now put on the hinges 3.2.
Severe structural damages had been caused to the visor in the winter 1993/4. The result was that the whole geometry of the visor was changed and that nothing fitted anymore.
Note August 2000 - the writer now believes that the Atlantic lock did not fit at all and was thus not in use when the accident occurred.
The deck hinges had been manipulated. In fact the Germans showed that the hinge bushes had been replaced in such a manner that their load carrying capacity was drastically reduced. However, as shown in 3.3, the hinges were only required when opening and closing the visor, when the maximum load experienced was of the order 119 tonnes (in tension), when the visor was almost closed and the visor arms were horizontal. Had the hinges been broken in service, this would have taken place when the crew tried to open the visor in port. As the visor was clearly opened and closed at Tallinn on the 27th of September, the visor hinges could not have been so bad as suggested by the Germans - the load carrying capacity had been reduced by the burning marks to a mere 20% of the original load carrying capacity (page 16 of (11)).
The Atlantic lock had been renewed and reinstalled at a different location already in 1981/2 with only 3 mm welding seams between the bushings/lugs instead of 8 mm original. The lock had also been repair-welded in a very unqualified manner that resulted in considerable loss of it load-carrying capacity (X ... has cut off the upper parts of the three steel lugs holding the bolt .... bushings .... After having removed these parts he has welded the bolt ....bushing into positions, fitting .... the changed position of the visor lug...). The visor lug had also been manipulated in different ways obviously to make the bolt fit through the bore of the lug.
The Atlantic lock hydraulics were not working and the locking pin had to be hammered in and out of the lock. The inside of the visor was covered by a hydraulic oil film.
Note August 2000 - the Germans have not concluded, as this writer, that the Atlantic lock was probably damaged before the accident and was thus not even used on the fatal voyage.
The side locks had a play of 10 mm and it had to be assumed that the condition of the side locks were no more original.
According to the German Group of Experts the ramp was also not maintained properly.
The ramp weathertighness was not maintained. The Germans found that one hinge was definitely damaged and that two side locks were probably not lined up and could therefore not be used. This meant that the ramp was leaking. However, the leaking could not have been serious and the crew was aware of the problem and fitted temporary packings (by cloth and mattresses) to stop or reduce the leaking 2.21. The Germans make a big story about this defect, but the writer thinks that the defect was not particularly serious and did not affect the seaworthiness of the ship. The Commission in (13) says that the ramp was weathertight and undamaged.
The German Experts allege that the primary causes for the sinking of the Estonia were (a) the extremely bad maintenance condition of visor and bow ramp, their hinges and locking devices, in connection with (b) a completely wrong loading of the car deck and a highly excessive speed under the prevailing wind- and seastate conditions, which had been forecasted (11).
With regard to the visor the Germans suggest that it was full of water, so the ship trimmed on the bow. Water also leaked onto the car deck through the leaking ramp. The Germans do not quantify the leakage in tonnes/minute or comment upon the fact that water leaking onto the car deck is drained out through the scuppers. The Germans then suggest that the visor hinges broke first (and not last as alleged by the JAIC 1.11 followed by the side locks. The visor then apparently moved forward and dislodged the ramp from its locks as early as 00.45-00.46 hrs and fair amounts of water started to enter the car deck. The visor was held back by the hydraulic pistons resting against the bulkhead/beam at frame 159. The inflow in tonnes/minute is not quantified.
The Germans then suggest - without published proof - that the crew observed the loose visor, reduced speed and turned the ship into the wind and tried to secure the loose visor (item (g) on page 37 of (11)). The ship was then upright, but at 01.02 hrs the ferry suddenly and abruptly heeled rapidly to starboard to an estimated angle of about 50°, however, almost uprighted shortly afterwards and then took a list of about 15° to starboard, which was slowly increasing. This is a very important observation backed up by the proof that many persons aboard hurt themselves and loose items fell when the ship heeled over. The Final report (13) does not mention anything of that.
Interestingly, the Germans then assume that the starboard side of the visor was pushed upwards due to buoyancy caused by the extreme heel, which also broke the Atlantic lock, and the visor was now only connected to the vessel by the two lifting cylinders.
The Germans then suggest that the list increased due to additional water quantities on the car deck streaming in through the partly open bow ramp, all of which accumulated at starboard side, and shifted the cargo and led to the increasing list.
Then the Germans make an incorrect suggestion. They say:
' ... at about 01.20 the visor was moving forward whilst the hydraulic cylinders broke through the front bulkheads and the visor separated from the vessel, the list then must have been 50°-60° and water streamed onto the car deck as well as onto the lower decks in increasing quantities'.
What the Germans fail to realise is that at 50°-60° list the vessel is never stable with water on the car deck - she will always turn upside down. At 50°-60° list no water can stream from the car deck onto the lower decks as the car deck is watertight and the openings to the lower decks are high above the alleged water on the car deck, 2.16 and 5.5.
(Note August 2000 - the Germans (Mr. W. Hummel) has later admitted in a newspaper interview that the ship should have turned turtle at this time).
As can be seen from figure 3.10 the visor can hardly dislodge the visor before the hydraulic cylinders broke through the deck beam at frame 159.
Therefore the German accident scenario is not convincing. So how could the 'Estonia' sink?
3.18 The Sauna was flooded and no. 1 Deck was flooded
The sauna is on the tanktop (deck no. 0) forward. The Germans say in (11) (page 36) that:
'According to statements of most survivors, in particular of the key witnesses ........ Passenger CÖ (cabin 1049 - 1st deck) ... Passenger MN - cabin 1027 - 1st deck, Passenger BN - cabin 1026 - 1st deck) ...... the sequence of events must have been somewhat different from what the JAIC has found and also what the authors Hellberg/Jörle assume in their book 'Katastrofkurs' (10), because ......... (b) there was water on the 1st deck, ... , in particular in the forward part, already before the sudden starboard heel occurred; (c) the sauna/swimming pool compartment on 0-deck ...... was flooded and under pressure, i.e. open to the sea, before the sudden starboard heel occurred .... '.
There are several other witnesses stating that there was water on deck no. 1. The Commission in its Final Report ignores all these testimonies, because it cannot explain how water flowed up on deck no. 1 before the sudden starboard heel occurred.
The writer finds it amazing that the JAIC ignores clear statements to the effect that 'Estonia' was leaking. These statements might not have been clear when the JAIC made its first statement on October 4, 1994 1.4 but must have been clear later. The statements about water on the car deck are not very convincing - the third engineer says he saw water on the car deck, the systems engineer says he didn't see any water on the car deck, but that the third engineer told him, that there was water on the car deck, and the motor man says that he saw water on the car deck (after the sudden listing had taken place (at 01.15 hrs?) and when all water should have been down in starboard aft corner), 4.7 and 4.23. Why the JAIC believes a third engineer saying that there was water on the car deck? Why believe him, when according the laws of nature, a ship with water on the car deck tips upside down, and the 'Estonia' did not do that? There are many questions that the JAIC does not answer in (13).