"Are those starships or submarines?"
A Monean research vessel was a type of spacecraft used by the Moneans during the 24th century. It was armed and capable of travel through both space and water, to depths up to a hundred kilometers. They posed no threat to an Intrepid-class starship and could be easily destroyed.
The USS Voyager encountered at least three of these vessels while in orbit of "The Waters" in 2375. (VOY: "Thirty Days")
For more information on this studio model, see VOY studio models.