Yes, something like that...! But with a big f*ck-off ram at the front end. ;D I think the ship Wells is describing is definitely something bigger and badder than the real-life
Polyphemus, but still something long and low and nimble, so more cruiser-like than battleship-like. I believe some of the late C19th RN cruisers were designed to act as rams when ramming was still considered a viable tactic in fleet battles, so the vision in my head is something along those lines, but maybe with scaled-up versions of some of
Polyphemus's design quirks. You know, for the fun of it.