narrow boat vs canal boat

narrow boat and canal boat both are nouns.

Word	Noun	Adjective	Verb	Adverb
narrow boat	Yes	No	No	No
canal boat	Yes	No	No	No

As nouns, narrow boat and canal boat are synonyms defined as:

narrow boat and canal boat: a long boat that carries freight and is narrow enough to be used in canals

Other synonyms of narrow boat include narrowboat.

narrow boat (noun)	canal boat (noun)
a long boat that carries freight and is narrow enough to be used in canals	a long boat that carries freight and is narrow enough to be used in canals