How close was US Navy-Royal Navy cooperation, and what role did the GIUK sonar line and trawlers play?
Short answerCooperation was very close; the GIUK line and trawlers supported the ASW barrier, though there were not enough assets for every demand.
NotesUnited States Navy-Royal Navy cooperation was very close and reinforced by frequent exercises. The GIUK surveillance line helped detect submarines moving from northern bases toward the Atlantic. Trawlers and other auxiliary vessels could contribute to the wider barrier and mine-countermeasure system. Technology and allied cooperation still could not solve the recurring shortage of platforms for every task. Sensors, exercises, and numerous relatively humble vessels all supported high-end anti-submarine forces.