fin keel vs centerboard

fin keel and centerboard both are nouns.

Word	Noun	Adjective	Verb	Adverb
fin keel	Yes	No	No	No
centerboard	Yes	No	No	No

As nouns, centerboard is a hyponym of fin keel; that is, centerboard is a word with a more specific, narrower meaning than fin keel:

fin keel: a metal plate projecting from the keel of a shallow vessel to give it greater lateral stability
centerboard: a retractable fin keel used on sailboats to prevent drifting to leeward

Other hyponyms of fin keel include centreboard, drop keel, sliding keel.

fin keel (noun)	centerboard (noun)
a metal plate projecting from the keel of a shallow vessel to give it greater lateral stability	a retractable fin keel used on sailboats to prevent drifting to leeward