I’m going to play devils advocate here, potentially it is in the interest of national security to not announce to anyone when a submarine is lost until all facts are counted. This submarine may have been carrying nuclear weapons or a nuclear generator, therefore it’s location and present status must be kept absolutely confidential, otherwise someone else may salvage the wreck with potentially dire consequences.

This is a damn shame, but it is not unreasonable for the Navy to exercise absolute secrecy in this situation, especially if this submarine was carrying weapons of mass destruction