US Navy Destroyer Escorts of World War II (epub)

Destroyer escorts first went into production because the Royal Navy needed an escort warship which was larger than a corvette, but which could be built faster than a destroyer. Lacking the shipyards to build these types of ships in Britain, they ordered them in the US. Once the US unexpectedly entered World War II, its navy suddenly also needed more escort warships, even warships less capable than destroyers, and the destroyer escort was reluctantly picked to fill the gap.