The photon torpedo room¹ of the refitted USS Enterprise NCC-1701 was seen in Star Trek II: The Wrath of Khan, and briefly in Star Trek III: The Search For Spock. The photon torpedo room is where Saavik shed a very Vulcanly tear, Scotty played "Amazing Grace" to a crew that had evolved beyond religion, and the esteemed commander of Starfleet told Kirk and Scotty that the 40-year-old Enterprise was 20 years old.

The photon torpedo room seems to be located near the photon torpedo launchers of the Enterprise, which are visible on the ship's exterior. More than once in Star Trek II, we see a torpedo lowered from above the photon torpedo room to one end of a track that runs along the center of the floor of the room. Once the torpedo is on the track, it moves forward along the track and into a chamber at the front of the room. Once the torpedo is in the chamber, a hatch seals the chamber from the remainder of the room, and then the torpedo is launched from the ship.

The photon torpedo room is also located near at least one of the Enterprise's port side airlocks. In Star Trek II, Kirk and crew are seen to board the Enterprise from their travel pod via the photon torpedo room.

It appears that the Enterprise may have more than one photon torpedo room. In the scene where Kirk and company board the Enterprise from their travel pod, one can clearly see a sign that reads "TORP BAY 2."

The "TORP BAY 2" sign suggests that the Enterprise has at least two photon torpedo rooms, and that the rooms are actually called "torpedo bays." Since the Enterprise has two photon torpedo launchers that are adjacent to one another, it's reasonable to assume that the other torpedo bay is adjacent to Torpedo Bay 2. Further analysis of other scenes in Star Trek II seems to support this assumption.

It thus appears that the Enterprise has two photon torpedo rooms or "torpedo bays." Torpedo Bay 1 supports the starboard torpedo launcher, and Torpedo Bay 2 supports the port torpedo launcher... or does it?

Spock's casket had to be launched from the starboard torpedo launcher, because the Enterprise's port torpedo launcher had been disabled during her battle with the Reliant.

Since Torpedo Bay 2 seems undamaged during Spock's funeral, one could argue that Torpedo Bay 2 managed to shift from being on the port side of the Enterprise when Kirk and crew boarded the ship, to the starboard side, where it avoided damage from Reliant's phasers, and was available for use during Spock's funeral.

On the other hand, Torpedo Bay 2 could have been repaired prior to Spock's funeral. It's possible that, forward of the hatch at the front of the room, there's a horizontal track running port-to-starboard that allows a torpedo bay to deliver a torpedo to either launcher. Since rooms have never been seen to shift locations within the Enterprise, this would seem to be the more reasonable explanation.

To summarize, the refitted Enterprise has two torpedo bays. Torpedo Bay 2 is located on the port side of the ship, and Torpedo Bay 1 is on the starboard side of the ship. Each torpedo bay is capable of delivering a torpedo to either launcher.

Our analysis would be complete except for this shot:

This shot takes place as Kirk orders the Enterprise out of orbit and toward the Mutara Nebula. There now appear to be at least four torpedo bays aboard the Enterprise. The room seen in this shot would appear to be Torpedo Bay 4, and Torpedo Bay 3 seems to be located past the exit to the left in the image above. Since the Enterprise's torpedo launchers point forward, the airlock seen in this room must reside on the port side of the ship. There's just one problem -- there are only three circular airlocks on the port side of the Enterprise, and all have been accounted for.

The airlock on the saucer was used by Kirk and Spock in Star Trek: The Motion Picture when Spock left the ship to explore and mind-meld with V'Ger. The inside of the airlock facility was seen in the movie, and it wasn't a torpedo bay.

The airlock at the base of the ship's "neck" was seen earlier in Star Trek II. It opens into Torpedo Bay 2.

The airlock on the side of the engineering hull opens into the Enterprise's cargo section and hangar bay. This airlock was used by Kirk and Scotty when Kirk assumed command of the Enterprise in Star Trek: The Motion Picture.

It would thus appear that Torpedo Bay 4 and Torpedo Bay 3 can't exist on the Enterprise. Some of the senior-class cadets aboard the Enterprise must have switched the signs in Torpedo Bay 2 in order to play a practical joke on some first-year plebe.

In conclusion, there are two torpedo bays on the Enterprise, and at least one cadet who deserves a reprimand for horseplay. All the mysteries of the Enterprise torpedo bays would seem to be solved.

Or are they? After boarding the Enterprise, Kirk and McCoy exit Torpedo Bay 2 through an exit at the port-forward corner of the room.² Spock then orders "Company dismissed," and the crewmembers exit the room so that Spock and Saavik can discuss how human and imperfect Admiral Kirk is. Another mystery rears its ugly head in this shot of the dismissed crew.

Three medical trainees are seen to exit the torpedo bay through the airlock. Where are they going? Kirk, McCoy, Sulu, and Uhura just entered the room through the airlock, and they arrived in a travel pod. Evidently the medical students are the smartest cadets aboard the Enterprise. While the engineering, science, security, and command-department cadets voyage to where Chekov has gone before, the med students hop a travel pod to crash a Saurian brandy keg party back on Earth.

I'll leave the minor mysteries, such as how two torpedo bays, the vertical intermix shaft, and turbolifts are arranged within the base of the Enterprise's "neck," to someone else.

To those of you who insist that there must be at least four torpedo bays on the refitted Enterprise because the wall signs say so, I propose another refit for the big "E":

¹ The photon torpedo room set was an extensive redress of the Imperial Klingon Vessel Amar bridge from Star Trek: The Motion Picture. The most noticable elements from the TMP set that were retained in the torpedo room are the massive, angled "shock absorbers" that run floor to ceiling. The black structure containing the hatch at the forward end of the torpedo room was the Amar bridge's main viewscreen. The wall-mounted control panel near the torpedo room airlock was probably the same unit from the saucer airlock set in Star Trek: The Motion Picture.

² Where did Kirk and McCoy go when they exited Torpedo Bay 2, on the port side of the Enterprise's "neck," through the port-forward doors? Given Kirk's lack of familiarity with the refitted Enterprise in Star Trek: The Motion Picture, he probably led McCoy into a broom closet.