The fans behind the nacelle caps are clearly for underwater propulsion. They should however operate unimpeded were they to be obstructed by anthropomorphic weapons arrays.
Only question is, what manner of woven (possibly straw) covering is capable of protecting the bridge dome from the extreme pressures of undersea travel? Could it be stylish and central american, perhaps?
Might the Enterprise require large, visible sensor globes atop this covering? With their large white surfaces, and small dark apertures, they may appear to be silly googly eyes, but such an addition would be a necessity.
Are there oars out the side of the engineering hull like a Roman Liburna to assist with propulsion? How is the ship steered?