how did new technology help even up the game with the deadly german u-boats during wwII?

Answer 1

sonar is part of the answer....radar was even more important, because WW2 subs.German Brit American whoever..were surface craft that could submerge.....they had to run on the surface to catch targets , recharge batteries, receive radio messages........and with radar available after the beginning 1942 the escorts could spot a U-boat sneaking in on a convoy.

Almost as important was RDF, radio direction finding....American subs only used their radios when in contact with a convoy and were independent..German subs were closely controlled by shore command, received messages every day and HAD to transmit at least once a day....this allowed RDF stations ashore and on escorts to get a line of bearing to U boats and allowed the Admiralty and Western Approaches Command to route convoys around some subs or send hunter killer escorts or ASW airplanes to the neighbor hood of a surfaced transmitting U-boat.....once forced to dive a U boat was limited to about 5 knots and most convoys could outrun them; once passed, a Boat would have to surface to chase, use its radio to report, be detectable by radar........

Answer 2

Die Rückseite der neuen Technologie dann wurde Sonar genannt.