Leonard B. Smith was an American pilot who spotted the German battleship Bismarck prior to its being sunk by British naval and air forces. Smith is sometimes considered the first American to be directly involved in World War II for his actions.
There are conflicting accounts of his involvement. According to Ludovic Kennedy, in his book on the Bismarck, [1] a number of US pilots, who had ferried Catalinas across to the UK and were supposed to familiarize the RAF crews with the plane, were unofficially used as copilots on operations. "Unofficially" because the USA was not at war with Germany at that time. Smith was acting as copilot of AH545 WQ-Z of No. 209 Squadron RAF which had been specifically assigned a search area after contact was lost with the Bismarck and was at the controls when the battleship was spotted around at 10:10 on 26 May. He jettisoned the depth charges and made for cloud cover under heavy AA fire, losing sight of the Bismarck and never regaining contact. Two other Americans were also in Catalinas that spotted the Bismarck later in the day: Lt Johnson in M of No. 240 Squadron RAF, and Ensign Rinehart in O of No. 210 Squadron RAF.
An alternative version runs as follows. As an experienced pilot, Smith was leading British instructional exercises while leading a patrol. When the patrol spotted the Bismarck, Smith broke from the formation and gave pursuit, following the ship for 18 hours before returning to a base in Ireland with 250 gallons of fuel.