weather ship vs watercraft

weather ship and watercraft both are nouns.

Word	Noun	Adjective	Verb	Adverb
weather ship	Yes	No	No	No
watercraft	Yes	No	No	No

As nouns, watercraft is a hypernym of weather ship; that is, watercraft is a word with a broader meaning than weather ship:

weather ship: an oceangoing vessel equipped to make meteorological observations
watercraft: a craft designed for water transportation

Other hypernyms of weather ship include vessel.

weather ship (noun)	watercraft (noun)
an oceangoing vessel equipped to make meteorological observations	a craft designed for water transportation
	skill in the management of boats