Here's something else I wanted to add to this discussion:
In 1976, Geoffrey Mandel drew up his own plans for the Independence-class, a class of Federation starships (Class II) based closely on the Starship Huron as seen in TAS' "The Pirates of Orion". Mandel's supposition was that the Independence and the Huron were both of the same starship class. Mandel's plans,
displayed in their entirety on the Cygnus X-1 web-site, depict a space vessel much smaller than the TOS/TAS Starship Enterprise.
U.S.S. Independence, drawn by Geoffrey Mandel
Class II Federation starship, Mk XVI Freighter design
Overall Length: 82.05 meters (269.19 feet)
Overall Wingspan: 55.8 meters (183.07 feet)
Overall Height: 34.5 meters (113.19 feet)
Mass: 11,300 tons
Ship's Compliment: 6 line officers, 19 crew
Ship's Passenger Capacity: 12 supercargo
Ship's Armament: 2 phaser banks, 2 batteries each (2 fore, 1 port, 1 starboard)
Ship's Transporter Mechanisms: 1 six-beam personnel facility, 2 cargo beam-units.
Mandel did take artistic license with his design, making it vaguely similar to the TAS Huron. He provided Franz Joseph Schnaubelt-style schematics, including detailed deck plans. Interestingly, he gave the Independence many facilities patterned after FJ's concept of Class I starships like the Enterprise, albeit scaled down. The ship offered substantial equipment, facilities and amenities for its crew and passengers, including being armed with external phaser banks, a substantial command deck, science lab, sickbay, Enterprise-style engine room, shuttlecraft hangar, full suite of maintenance and crew support facilities, mess hall, transporter rooms, theatre, briefing room, gym and rec areas. Mandel really tried to visualize a complete and functional Federation starship. There was even a fire control room and an Auxiliary Control room. I am amazed!
There are some aspects of Mandel's plans that I am not a fan of. Mandel took the names of various space vessels from TOS (Antares, Dierdre, Astral Queen, Carolina) and incorporated them into his class. That's probably some of the boldest artistic license of all. Of those names I listed above, only Antares and Carolina are explicitly said to be Federation starships / "U.S.S." as spoken by TOS characters. The others could be legitimately debated. There was also no indication in "The Pirates of Orion" that the Huron (explicitly shown and said to be a Federation starship) was armed. We only ever saw Huron try to evade the Orions, there was never any evidence of her firing on them.
Despite Mandel's license, probably the biggest questionable assertion in these plans would be the ship's size and capacity. This ship is shown to be less than one-third the size of the Enterprise, and with a crew of 25, with room for another dozen passengers. In TOS' "Bread and Circuses", Spock reported that the S.S. Beagle, a merchant service ship, as a "Class Four star-drive vessel, crew of forty-seven.." It could be said that the merchant service may be a civilian arm of the Federation, or perhaps of UESPA. But if a Class IV ship could house 47, I would expect a Class II ship to house at least twice that number. But that's just me.
Independence does have an impressive internal arrangement, with specific functional compartmentalization of facilities. There's a dedication command deck and support services section up forward, a nice cargo bay with hangar deck amidships, and a crew's quarters/engineering sections in the aft end.
Given what we know about how ships in the STAR TREK Universe are built/arranged, I'm tempted to say that the FJ-style suppositions on bulky ship's facilities are unnecessary, and could each be smaller and more decentralized. The ship probably would not need to house a computer the size of a large room. Other than that, I would say that an impressive Class II ship like this might be somewhat larger and house more crew and passengers. I would also expect it to have the capacity to also serve as a warptug.
In "Friday's Child", Sulu suggested that a freighter would only be able to manage Warp 2 at best. But he said this when the concern at hand was a faked distress call from the (possibly civilian/merchant service) S.S. Dierdre. Would the Indepdenence be as limited, or would her profile make her more capable? Mandel's plans don't address this.
What do you think?