Complex sentence: For his next tour, he was named as the commanding officer of the aircraft carrier, but she was sunk on 7 June 1942 in the late stages of the Battle of Midway before he could report aboard.
Split into simpler sentences: For his next tour, he was named as the commanding officer of the aircraft carrier. However, the ship was sunk on 7 June 1942 in the late stages of the Battle of Midway before he could report aboard.