prolonge knot vs sailor's breastplate

prolonge knot and sailor's breastplate both are nouns.

Word	Noun	Adjective	Verb	Adverb
prolonge knot	Yes	No	No	No
sailor's breastplate	Yes	No	No	No

As nouns, prolonge knot and sailor's breastplate are synonyms defined as:

prolonge knot and sailor's breastplate: a knot in the rope used to drag a gun carriage

prolonge knot (noun)	sailor's breastplate (noun)
a knot in the rope used to drag a gun carriage	a knot in the rope used to drag a gun carriage