weather ship vs vessel

weather ship and vessel both are nouns.

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

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

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

Other hypernyms of weather ship include watercraft.

weather ship (noun)	vessel (noun)
an oceangoing vessel equipped to make meteorological observations	a craft designed for water transportation
	an object used as a container (especially for liquids)
	a tube in which a body fluid circulates