Some time ago I performed a comparative analysis on TOS era starships. That paper used technical specifications from appropriate "references" to derive interesting physical quantities related to those ships. (Curious readers can find it posted on my website.)

For example, calculations on the NCC-1701's saucer section (the primary hull, for the purists) show a mass of 60-some thousand metric tons and a habitable volume of about 90000 cubic meters (well over a hundred good sized houses). Her warp nacelles come in at approximately half that for each parameter (36700 m^3 and 31500 t respectively).

Well as of late sufficient NX-01 specifications have popped out to crunch similarly, hunting for something important. So I took the TV Guide overhead of the ship and transferred it to graph paper, and from there extracted measurements which were normalized to the 190m length provided in the Writer's Guide.

(I am aware that a previous length of 230m has been knocked around. This number would certainly allow for longer warp engines yet the Guide number allows a more realistic hull size as shown below. Also note that 190 + 230 = 420.)

I began by modeling the warp engines as two simple cylinders roughly 83m long and 11m in diameter (TOS nacelle: 141m long and 18m across). This establishes each NX-01 warp engine to displace roughly 8000 m^3, approximately one-fifth the size of a 1701 nacelle.

Proceeding with the analysis, the different ship-shapes called for a new model than before. The NX-01 primary hull was simulated in three dimensions as an ellipsoid: 50m by 40m by 10m. (The "outrigger runners" do not appear to predominate like they do on the Akira class and were neglected.) These figures yield a habitable volume of around 80 thousand cubic meters.

This puts Archer's primary hull quite near the size of Kirk's! This result is counter-intuitive given the crew complement of the NX-01, rated at 87. The NCC-1701 has roughly twice the usable volume but five times the crew size. (Or maybe Kirk could handle it, being a "fair" psychologist.)

Now assuming Scotty's and "Trip" Tucker's nacelles are equally dense (not a safe assumption perhaps), they should mass roughly one-fifth as much - about 10 to 20 thousand metric tons together. Since the overall NX-01 specs in at 80000t this leaves between 60 and 70 thousands tons for the primary hull. With slop this value equals that of the 1701, and this tends to confirm that the primary hulls of Archer and Kirk are sized much to the same order.