patent log vs screw log

patent log and screw log both are nouns.

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

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

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

Other synonyms of patent log include taffrail log.

patent 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