The USS Merrimac (NCC-1715) was a Federation starship in service during the 2270s.
The Merrimac was mentioned by name and registry in comm chatter transmitted by Epsilon IX station. (Star Trek: The Motion Picture)
Background
Franz Joseph's Star Fleet Technical Manual lists the Merrimac as a Template:ShipClass starship.
The comm transmission of this starship was cut from the director's cut.
A USS Merrimac is mentioned several times in Star Trek: The Next Generation episodes. However, we assume all the information refers to the mid-24th century Template:ShipClass USS Merrimac.