The plots have not been analyzed by JAIC or other parties. Without any fact JAIC concluded the last voyage on a number of assumptions, such as departure time, route and speed. They didn't even bother to interrogate the second M/V Estonia crew to determine the normal route for the ship. As to the weather situation they assumed it to be worse than their own investigation proved, something that did not stop them from stating that the weather situation was extreme during the last voyage.
From various sources, not used in this report as evidence, we have got information that M/V Estonia's normal route from Tallinn was through the north exit, not through the west bound exit as JAIC assumed. After leaving the north exit a north west course was set to join the other ships in the traffic separation zone, following the same in an almost westerly course. The reason was mainly a safety matter as they then followed the zone together with the other ships and thereby they never had to cross the traffic zone in mid night and unfavorable angle (not permitted/recommended). But it is also true that M/V Estonia used two alternative routs, one called the "South route" and one called the "North route". See the following picture.
The both M/V Estonia routes (green arrows) had in common the north exit in and out from Tallinn. Both routes also followed the traffic separation zone and the other ships (blue and red arrows) in the Gulf of Finland. The South route was heading for Stockholm via Sandhamn, and the North route also heading for Stockholm was via the north entry at Söderarm. When M/V Estonia on route from Tallinn should use the South route they had to alter the course to avoid meeting the fleet from Stockholm to Finland in a small and dangerous angle. Therefore they followed the traffic separation zone to the south (south west of Hangö) before changing course towards Sandhamn.
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