Your conclusion is correct in that the ship was useless, but they were 16"/45s, and Gibbs designed the ship to try and sell it to the Soviets, so the Panama Canal limitation doesn't matter as much.Not really.
- That's a very small flight deck to work from, it looks even smaller than a Bogue's 440ft flight deck. So maybe you're carrying 24x aircraft.
- The turret shape looks like 14" guns, not 16".
- The flight deck amidships means that the armored citadel/raft is much bigger than the Iowa or maybe the Montana. Which means that it's very heavy, probably accounting for the extra beam.
- It appears to be too wide to travel through the Panama Canal, which is a major operational limitation.
- 6x shafts means rather immense fuel consumption.