Vixen
Penultimate Amazing
Since you are concerned that posters should not twist each others words I'll just note that Abaddon did not say 'so there were no communication problems'.
Plainly the people who could not get out of the Estonia were not going to be rescued by other ships no matter how soon they arrived, but no other rescuers would arrive any sooner than the nearby ships. So it is they who needed to know the Estonia's location with the greatest urgency and the Estonia took until about 01:29 to report it to them. No mystery blackout is needed to explain this, only the Estonia's crew failing to grasp soon enough what terrible danger they were in and not reacting appropriately for several crucial minutes.
This is like wading through treacle. If a ship sinks with zero prospect of rescue, then do you not think sabotage should be investigate, especially with the highly surprising - to marine experts - lack of radio network and EPIRB's not automatically activating when triggered by two fathoms of water and the complete disappearance of the vessel when professional training and academic examinations has scientifically taught you (a) the time it takes for a capsized vessel to sink with its hull intact ceteris paribus and (b) the physics of sinking and floating, bearing in mind the Wilhelm Gustloff which was triple torpedoed in the hull took 45 minutes to sink completely and the Titanic, broken in two and having hit an iceberg, causing damage to its watertight bulkheads and weakening its rivets, took almost three hours to sink.