Complex sentence: In August 1943, Kennedy's "PT-109" was sent out north on a night mission through Ferguson Passage to Blackett Strait, and was one of 15 boats sent to intercept the Tokyo Express.
Split into simpler sentences: In August 1943, Kennedy's "PT-109" was sent out north on a night mission through Ferguson Passage to Blackett Strait. She was one of 15 boats sent to intercept the Tokyo Express.