Complex sentence: On 25 May 1941, Hughes and several other women were briefed on the search for the "Bismarck"; she shortly thereafter decoded a message referring to the "Bismarck" and detailing its current position and destination in France.
Split into simpler sentences: On 25 May 1941, Hughes and several other women were briefed on the search for the "Bismarck". Shortly thereafter she decoded a message referring to the "Bismarck" that detailed its current position and destination in France.