I'm sure this has been stated before (it pretty much echoes arguments I've seen on the web), but I'm bored and wanted to check for myself. Using this schematic:
I get the following measurements. Assume the hatches in the neck and secondary hull at 2.5m wide (reasonable, based on what we've seen, incl. in the new trailers where they spacewalk), you find:
- Primary hull diameter = 238 m
- Secondary hull length = 189 m
- Total length (excluding nacelles) = 343 m
- Height = 97.5 m
- Max. width of secondary hull = 45 m
- Max. height of secondary hull = 39 m (measured from base of neck)
- Width of hanger deck (at doors) = 26 m
- height of hanger doors = 8.5 m
- Bridge viewscreen / window = 8.5 m
- Round porthole window diameter = 0.6m
- Diameter of "bridge" dome = 9 m
- Bridge diameter = 18m (assuming it fills the space between the two "side" windows)
Every one of these dimensions seem quite reasonable to me, and obviously the exterior form of the ship was designed to basically match that of the TMP refit.
There are TWO problems. If shuttles are 40ft long (12m), as someone stated, then you can only park them sideways if you have 2m between them. If shuttles are 30ft long (9m), then you can basically park 3 end to end across the shuttle bay -- kind of what we see in the movie.
The second problem is with the viewscreen height. According to that diagram, it would be 1.25m high (a little over 4ft). Obviously we see Kirk standing tall with room to spare, suggesting that it is about 2m high. Of course, it could be a resolution issue on the above diagram.
But if you scale the ship based only on these two artistic elements
(because they "look cool"), portholes become unreasonably large, the hatches become a ludicrous 4m across, etc...