For all we know, the Ba'ul are the Preservers, treating lower races as cunningly forced labor and monitoring them with obelisk technology. Nothing as straightforward as laser-whips and forcefield fences: instead, the Ba'ul appear as benefactors to their victims, in a variety of ways, while making them harvest kelp or process diverted asteroids into precious minerals or whatnot.
Or then the Preservers gave the Ba'ul obelisk tech to Preserve them, back when the Kelpien were trying to exterminate the species.
Or then every two-bit slaver purchases from the same vendor.
Or then <quick check; okay, at least six pages since I last claimed this> the Discovery is a former shuttlecarrier, internally renovated into a flying laboratory, with mushroomrooms and other weird stuff suspended inside the vast hangar cavity, but most of the space left empty save for creatively rerouted turborails and random logistics spaces. Properly separated landing bays and launching tubes would be a must for such a carrier.
...What were these tubes supposed to be in the original McQuarrie drawings? They're part and parcel of all the versions, but there seem to be separate "impulse engines" or other rocket-analogues on the back wall of the hull, flanking the bay doors.
It's funny how the ship actually seems to have zero identifiable torpedo tubes anywhere on the hull. But that's just par for the TOS course.
Timo Saloniemi