This is the ship my PCs are currently on, cruising through the Underdark with a crew of orogs whose occupation might be described as “often but not always pirates.”
Since the Underdark lacks wind, this ship lacks sails. Instead, it’s powered entirely by rowers on the lower deck. And since the Underdark is a dangerous place, this ship is equipped with a pretty solid arsenal of weaponry. Still, there’s nothing here that rules it out as a surface ship if you’d prefer to use it as one. In the Greek and Roman times, this is more or less the kind of warship you might have seen.