Personnel assigned to the USS Yorktown during the late 23rd century.
Named
Unnamed personnel
Chief engineer
When the Yorktown was disabled by the Whale Probe near Earth in 2286, the ship's chief engineer attempted to deploy a makeshift solar sail so as to focus and absorb radiation from a nearby sun they were orbiting, with the hopes of generating power to keep the crew alive. (Star Trek IV: The Voyage Home)
This character was only mentioned in dialogue.
Ship surgeon
When Captain James T. Kirk of the USS Enterprise delayed the rendezvous with the Yorktown, Doctor Leonard McCoy reminded him that the Yorktown's ship surgeon would want to know how late. McCoy added that the vaccines he was transferring to Enterprise for the Theta VII colony were highly perishable. (TOS: "Obsession")
This character was only mentioned in dialogue.
Tuvok's father
This Vulcan was the husband to T'Meni and the father of Tuvok.
During the 2270s, he sent his son to a Vulcan master to deal with a case of shon-ha'lock. (VOY: "Gravity")
In 2289, he and T'Meni sent their son Tuvok to Starfleet Academy, as it was their wish that he become a Starfleet officer. Feeling obliged to honor his parents' wishes, Tuvok consented to attend. (VOY: "Flashback")
Four years later, he was serving aboard the Yorktown when he sent a letter to Tuvok, who was serving as an ensign aboard USS Excelsior. (VOY: "Flashback")
This character was only mentioned in dialogue.
According to Star Trek: The Magazine Volume 2, Issue 11, p. 52, Tuvok's father's name was Sunak (β). He was further referenced in the novels Pathways and The Sundered.