iceboat vs ship

iceboat and ship both are nouns.

Word	Noun	Adjective	Verb	Adverb
iceboat	Yes	No	No	No
ship	Yes	No	Yes	No

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

iceboat: a ship with a reinforced bow to break up ice and keep channels open for navigation
ship: a vessel that carries passengers or freight

iceboat (noun)	ship (noun)
a ship with a reinforced bow to break up ice and keep channels open for navigation	a vessel that carries passengers or freight
a sailing vessel with runners and a cross-shaped frame; suitable for traveling over ice