sailing master vs navigator

sailing master and navigator both are nouns.

Word	Noun	Adjective	Verb	Adverb
sailing master	Yes	No	No	No
navigator	Yes	No	No	No

As nouns, sailing master and navigator are synonyms defined as:

sailing master and navigator: the ship's officer in charge of navigation

sailing master (noun)	navigator (noun)
the ship's officer in charge of navigation	in earlier times, a person who explored by ship
	the member of an aircrew who is responsible for the aircraft's course
	the ship's officer in charge of navigation