towing rope vs towing line

towing rope and towing line both are nouns.

Word	Noun	Adjective	Verb	Adverb
towing rope	Yes	No	No	No
towing line	Yes	No	No	No

As nouns, towing rope and towing line are synonyms defined as:

Other synonyms of towing rope include towline, towrope.

towing rope (noun)	towing line (noun)
(nautical) a rope used in towing	(nautical) a rope used in towing