taffrail log vs screw log

taffrail log and screw log both are nouns.

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

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

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

Other synonyms of taffrail log include patent log.

taffrail log (noun)	screw 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