Which one? I Netflix'ed my way through that whole show a couple years ago and didn't see any like that. It does sound a little bit like "Space Seed" from TOS

Which one? I Netflix'ed my way through that whole show a couple years ago and didn't see any like that. It does sound a little bit like "Space Seed" from TOS though, except I don't remember that ship having a particular destination. There was another TOS episode where they find a stray asteroid that turns out to actually be a generation ship inside. And there was some TNG episode where they find a ship with some 20th-century Earthers in cryogenic storage because they had just died of medical ailments. But I don't remember any ENT episodes like this, just some talk about "slow" Earth ships traveling at only Warp 1.5 or so, so that people lived their whole lives on them while on long-term trading missions (their helmsman came from one of these ships).