Be it the "Refit" Enterprise, or -A, virtually all the plans I have seen indicate the Vertical Intermix Chamber (seen in the Main Engineering Scenes in TMP and TWOK, and a modified version seen in TUC) is shown to extend from the bottom of the secondary hull through the neck to the "Impulse Deflection Crystal."
Is there any real reason to assume it must actually travel that way? Is there any on-screen evidence to indicate that it indeed connects with the IDC, or is that simply an assumption that seems to have universally been agreed upon?
Well, the reason that it's "assumed" that's the case is that Andrew Probert, who did the lion's share of the design on the TMP Enterprise, intended that to be the case with the TMP Enterprise. He even laid in "removable maintenance panels" along the side of the dorsal right over the path followed by the shaft.
Here's an interesting page from Andrew's own website... which you may find interesting.
But that doesn't mean too much, except insofar as the TMP Enterprise (1701(r) or 1701-A) are concerned. For any other ship... no, there's no real justification for it having to be "vertical"... except that they were reusing the same basic set over and over, throughout TMP, TWOK, TNG, and VOY, with significant redressing of course. They built them all with vertical engine "cores" because the set had a big hole for a vertical engine core.
There's no reason whatsoever that this type of "core" might not be entirely horizontal, or slanted, or go from side to side. It could be "V-shaped" without violating any of the "design rules" from the TNG Tech manual.
I am looking over any and all deck plans I can get my eyes upon, and every last one of them seems to show that, and while in theory it might make some sense, actually trying to fit it into the neck is problematic at best.
True. Of course, the torpedo room from TWOK was not what Andrew Probert had in mind for the TMP ship... which was a pair of energy-based launchers (no physical "casings") on either side of the reactor core... with the proximity being an advantage because, remember, photorps are effectively matter/antimatter bombs tossed around as projectile weapons (in TOS, with no evidence of them being anything but "dumbfire weapons" but with TWOK and on, gaining some minimal maneuvering capabilities)
The "torpedo room" in TWOK is actually a redressing of the "Klingon Bridge" set from TMP. (Go back and watch both and you'll see the same structural "shock-absorbers" in the same positions... and the "torpedo loading circle" on the floor is where the Klingon 1st Officer stood in TMP, behind the Klingon helm console.)
It never worked particularly well. The best solution is that there are twin torpedo rooms (which is really REQUIRED when you consider that, shortly after the port torpedo room is destroyed, the Enterprise fires torpedos from the starboard tube, implying that there are separate port and starboard rooms, identical to what we see in the various sequences.
In fact, go back and note where Adm. Kirk boards the ship (port side)... and note which tube fires to launch spot's "casket casing" (starboard).
The main issue, there, is that I don't think that there's actually room in the neck for both rooms as built. But if you can "adjust the room" a little bit... make it, say, 30% narrower... then it works fairly well.
As for ergonomics... the main lift has to be at the front of the dorsal, forward of the reactor core (though not nearly far enough forward as far as I'm concerned!) and between the two launch tubes (and loading bays). That's not really a problem... if you can make it all fit in, that is.
The REAL problem is that "Main engineering" ought to have a lift tube at the front entrance, not a corridor. I suppose that the tube might separate into two, on the deck immediately over main engineering, and so there are two "stations" on either side of the entrance? Even so... the corridor we see out that door can't be more than 10-15 feet long, and it's supposed to look like something more like 40 feet, I think (though with some forced-perspective if memory serves).
Trying to fit the torpedo tubes around it is neigh-on impossible, not without making some very poor ergonomic choices (do you really want the crew manning the Torpedo bays to have to pass through the intermix chamber room at every shift change? Do you really want to have one of your handful of exernal docking ports (one third of the primary ingress/egress points in spacedock - assuming the saucer edge on p/s, the secondary hull port that was used in TMP and the Torpedo Bay port used in TWOK) lead to people and any stuff they are carrying pass through the intermix chamber room almost non-stop while in dock? (yes, I know the ports were never seen to have been used for such, but the point still stands, why have a port in a location that makes it difficult to get to the remainder of the ship from? [/quote]Well, the "TWOK" version of torpedos gives us a very good reason for having a docking port there (which wasn't there with the TMP-Probert version). This is supposed to be a dedicated docking port for torpedo casing reloading.
How many "docking ports" and other non-transporter access paths does the TMP Enteprise have?
- The main landing bay (just listing it for completeness, not "really" a docking port.
- The two primary-hull-underside things... which seem perfectly nonsensical, really (an INCREDIBLE amount of wasted space there!)
- The main saucer "gangway hatch" on the port side (which DOES make great sense, actually, but was never used again after the TMP SFX sequences were shot, but SHOULD have been used in the "spacedock" sequences in ST-III and ST-VI, as far as I'm concerned.)
- The various "maintenance access hatches" on the top of the primary hull (waaay too many of those, but it did give them a cool sfx bit with Kirk, Spock, McCoy, and Ilia walking around on top of the hull, so....)
- The "standard docking port" on the back of the bridge module... which is utter nonsense to have there unless the bridge module could potentially be ejected and require docking for crew recovery later... but made sense from a "series shooting" standpoint, I suppose, since it meant that you could have more stuff set on the Bridge set without having to have the crew go off to some other set. Production practicality trumping design logic, in other words...
- The ports on the neck, which seem to be there for torpedo reloading, and COULD be there for "refueling" purposes (matter and antimatter) as well?
- The ports on the side of the secondary hull, which seem to be there for cargo transfer.
- The various underside-primary-hull hatches which seem to be there for loading of "consumables" items (I assume unprocessed food, water, atmosphere, replaceable filtering, whatever).
When docked... the most practical means of moving crew in and out really is the "main gangway hatch." The other hatches really are intended for specific purposes other than "crew transfer."
Why Kirk and Co boarded at the torpedo loading port is something of a mystery, except that the production had this new set and they wanted to use it... and didn't want to rebuild the cargo deck, or have to build the hangar deck or a "gangway" set...
Additionally, trying to fit both a turbo-shaft and the intermix chamber into the neck makes things very tight in the front (no good way to route the turboshaft around to aft of the intermix chamber, as in the saucer it would end up in the impulse engines before it could reach the neck).
Oh, it works just fine, except for the issue with engineering mentioned above. The intent was for the lift tube to be right there in the leading edge.
The problem is that the set designers didn't really bother to build sets that would fit inside the ship as designed. The ship itself works just fine.
Overall, it would be a much more functional ship for personnel to use if the intermix chamber did NOT go through the neck.
Except that part of the intention (as I recall, dictated by GR himself) was that the impulse and warp drive systems should be interconnected... and that there be a "vertical shaft" between the two.
I'm much more in favor of a sloped system, and of having the interconnection be a simple "power sharing" system rather than having portions of the generation be in both "halves" of the ship. But that's not now the TMP ship was designed.
If you're interested in how I, personally, do a starship design, well... I've done several, but at the moment I'm engaged in fleshing out the guts of the TOS Enterprise. You might find it interesting, since I'm addressing the very questions you're discussing, albeit for the earlier incarnation of the ship.