How did the US Navy diminish the effectiveness of Germany's Atlantic submarine fleet?

The U.S. Navy's Escorted Convoy system was the primary technique which started the pressure on the U-boats.

Along with the normal convoy escorts (light carriers, destroyers, destroyer escorts, etc.) there were several key elements that ultimately spelled the end of the German U-boat threat in the Battle of the Atlantic:

1. Advances in anti-submarine warfare techniques.

2. Recoverable aircraft launched for local area air patrols.

3. Advancement and employment of long-range bomber cover from both the U.S. and England.

4. British breakthrough in breaking Germany's Enigma code, which until that point in the war, was the single biggest factor in the U-boat's initial successes in the Atlantic Theatre.