drop keel vs centerboard

drop keel and centerboard both are nouns.

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

As nouns, drop keel and centerboard are synonyms defined as:

drop keel and centerboard: a retractable fin keel used on sailboats to prevent drifting to leeward

Other synonyms of drop keel include centreboard, sliding keel.

drop keel (noun)	centerboard (noun)
a retractable fin keel used on sailboats to prevent drifting to leeward	a retractable fin keel used on sailboats to prevent drifting to leeward