TheCodeBreakers
frustrated these efforts, and on May 5 her commander wirelessed home:
"Refueling impossible under constant stalking. Mid-Atlantic worse than
Bay of Biscay." Her "spurt" transmission—made by tape-recording the
message and then radioing the tape at high speed—lasted less than 15
seconds, but no fewer than 26 huffduff stations got bearings on it,
probably as a result of improved equipment that scanned the horizon 20
times a second and zeroed in accurately and semiautomatically on any
emission. Three hours later, an American plane spotted the U-boat; an
hour after that an American ship began to attack it, and within 25
minutes the submarine had gone down.
In addition to huffduff, an intercept network eavesdropped on the text
of the German messages. The Navy monitors could often tell one U-boat
from another by the sending characteristics of their radio operators, and
sometimes could ascertain the number of U-boats in a wolf pack. They
annaabi.ee 
