The USS El Cid (NCC-534) was a Saladin-class, Cochise-subclass destroyer in service during the mid to late 23rd century. (Star Fleet Technical Manual) In 2294, El Cid, commanded by Captain Gret, was one of many Federation vessels that engaged Tholian forces near Alpha Tucanae. El Cid was heavily damaged during the battle and had to be towed to Starbase 3 afterwards. While most of the surviving crew transferred to Excelsior, Gret stayed aboard, even though he'd have to do so in a spacesuit. (Orion Press: Chekov's Enterprise)