Question: Dixie Kiefer was Executive Officer of the aircraft carrier commisiioned by the Navy starting in what year?
Sentence (from "USS Yorktown (CV-5)"): She was named after the Battle of Yorktown in 1781 and the lead ship of the "Yorktown" class which was designed after lessons learned from operations with the large converted battlecruiser "Lexington" class and the smaller purpose-built USS "Ranger" .
Relevant evidence: No