Here’s a training film from World War II days as the DE program was ramping up. It’s apparently intended as an orientation for new sailors assigned to new construction.
The DE program was really almost wholly a result of Franklin Roosevelt. The Navy didn’t have a prewar plan for mobilization construction of the DE type, unlike many other combatants. It intended to use 173’ PCs and full size DD ships. Roosevelt helped the Navy change its mind. The DE program was hugely successful, with several hundred being commissioned between 1942 and the end of the war.
Further, the wartime DE program led to the further development of what we today call frigates. Quartermaster will tell us in the comments about his days aboard USS Courtney, a direct descendant from the wartime DE design.
With the exception of the extremely austere Claude Jones class, pretty much every post-war ocean escort class was quite successful. The various classes shared a few common traits. First, they were not intended to sail with the main striking force of the fleet, the carrier battle groups (though shortages of escorts meant they often did). They were balanced general combatants intended to escort amphibious shipping, replenishment groups, and merchant convoys. They emphasized anti-submarine warfare, but did not ignore anti-surface and anti-air warfare, if only for self defense.
They also tended to fill those seemingly endless extra missions that the Navy finds itself tasked with, but not requiring a more robust warship.
The last of the FFG-7 Oliver Hazzard Perry class frigates will be leaving the fleet shortly, to be replaced by the LCS, bringing to a close a 70 year history of ocean escorts in the US Navy.