Yes, that is the other solution to this problem (and also the one that Franz Joseph adopted, so it's got a good history!) If nothing else, it solves the viewing issues.
Do you have an in-universe explanation as to the mechanical reasoning behind the tapering shape?
Well, in order to answer the question let me review my thought process. My project is a slow going affair that I start and stop on for a few years now. I started it waaay back in 2005. My goal to make a set of deck plans for the TOS E that fit exactly what was shown on screen, to my best ability to reconcile it all. My mantra is "What would the Thermians do?" in reference to the aliens from Galaxy Quest
who innocently thought the show was real and managed to build a working replica based on images from the show.
Anyway, I got through so far a little over half the first season watched with a notebook in hand, drawing out each set as filmed and making notes as to which direction characters entered or left and where dialogue says they came from or are going to, the idea being to glean some clues as to how the various locations relate to each other in the volume of the ship. Now, given that I'm not quite 1/5 through the source material, I don't know if it's even possible to make any use of all this info, but it's fun for me just the same.
As far as the engine room goes, there are enough shots on "engine room" areas where the sets were obviously arranged out of wild sections on the morning of the shoot, where, to take all of this literally, there are probably dozens of separate engine room areas. This makes sense as there are dialogue references to the engineering sections being maze like and easy to hide in ("Court Martial") and various episodes where "engineering sections" are referred to as distinct from the regular deck space.
Also, there are shots in different episodes where the tapered pipe unit is seen surrounded by other walls and machinery arranged differently. My current working thesis is that those tapered pipes are essentially some form of power transformer where, on the bigger end, the power is lower voltage and on the small end, power is high voltage. Raw power comes into the unit at the small end and comes back out of the large end in a form more useful for the lower power needs of the ship's general equipment.
This research intensive project grew out of an earlier attempt to come up with deck plans. The multiple "engineering rooms" theory was the starting point for this project. Here:
is a thumbnail to go to a early idea I had for Deck 5. This is NOT the direction I'm going in for my current project, but it does illustrate one possible arrangement of multiple engine rooms with the tapered pipes being a power transformer instead of an engine component. My idea was that there is at least one episode where power is cut on one half of the ship, then the other. So I put one Engineering Room in each half of the ship in approximately the 1:00 and 5:00 positions. There would also be more of these types of room in the lower hull.
Anyhow, that's my idea, in more detail than I'm sure anyone bothered to read...
P.S. I used the hull pressure diagram to divide up the volume before i ever saw any of Shaw
's work.. That he used the same approach really got me to pay attention to his thread and my current ideas are at least influenced by his work. Great stuff!