Big Data.

 This is coolbert:

From MARCONI through Harry at Sharkhunters;

NEW [not exactly new] technology available for submarine detection. Traditional active and passive sonar now augmented by measures not acoustic.

   "Washington.....Today's submarines are in danger of becoming increasingly vulnerable as game changes in undersea warfare make it easier to detect them, a new report says."

     "Deep sea submarines have been a key part of the United States military's offensive and defensive missions for decades, but a significant part of their utility lies in their ability to operate stealthily. To this end, the US military has invested huge amounts of money into making submarines, in particular the Navy's Virginia-class nuclear submarines quieter.  But rapid increases in computer processing power are offsetting these advances. Submarine detection techniques that do not measure sounds but rather the wake left by submarines, for example, have been known for decades. But they have not been exploitable until very recently because computer processors were too slow to run detailed models needed to see changes in the environment caused by a quiet submarine, according to a report from the Center for Strategic and Budgetary Assessments (CSBA) released Thursday."

     "Today, 'big data is providing the capability to run sophisticated oceanographic models in real time, making these detection techniques more feasible. As computer processors shrink, some will soon be small enough to fit on the sea floor. These systems have the potential to make coastal areas far more hazardous for manned submarines, the report notes."

Such technology at this point in time the versatility of which confined to COASTAL AREAS and not the open ocean? Submarines operating in pelagic waters relatively safe as of now?
coolbert.