go down vs submerge

go down and submerge both are verbs.

Word	Noun	Adjective	Verb	Adverb
go down	No	No	Yes	No
submerge	No	No	Yes	No

As verbs, submerge is a hyponym of go down; that is, submerge is a word with a more specific, narrower meaning than go down:

Other hyponyms of go down include settle, subside, founder, submerse.

go down (verb)	submerge (verb)
grow smaller	fill or cover completely, usually with water
stop operating	cover completely or make imperceptible
be defeated	put under water
be ingested	sink below the surface; go under or as if under water
go under
disappear beyond the horizon
move downward and lower, but not necessarily all the way
be recorded or remembered