patent log vs taffrail log

patent log and taffrail log both are nouns.

Word	Noun	Adjective	Verb	Adverb
patent log	Yes	No	No	No
taffrail log	Yes	No	No	No

As nouns, patent log and taffrail log are synonyms defined as:

patent log and taffrail log: a cigar-shaped log with rotary fins that measure the ship's speed

Other synonyms of patent log include screw log.

patent log (noun)	taffrail log (noun)
a cigar-shaped log with rotary fins that measure the ship's speed	a cigar-shaped log with rotary fins that measure the ship's speed