Space Is An Ocean: Partially played straight, partially (and in all the scientific ways) averted. In rough order of examples:
The Imperial Navy does use some wet-naval terminology and protocol – but then, that’s only logical, because it was the wet navy that had all the experience in running small-town-sized vessels in hostile environments for extended periods of time, with little direction from home – just like starships. But if you were to examine this matter in detail, IN terminology and routines are probably about one-third wet navy, one-third air force, and one-third unique to their new environment.
(Also, while there are some class analogies to be made… and while there may not be schooners and canoes, there are clippers among the lighthuggers, and there are Space Junks, of exactly that kind, among the free traders… there are no lifeboats, escape pods, etc. Since Space Does Not Work That Way.)
Space is definitely not two-dimensional. In fact, one of the major impetuses for even fairly backward and morphological-freedom-hating species (of non-aquatic or non-avian heritage, anyway) to get with some of the transsophont program is that splicing the ability to handle the third dimension, at least, into your brain is one of the things most useful in preventing your fleet from losing horribly to anyone with a better head for strategy.
Space, obviously, does not have friction.
The IN does use naval ranks (except in the Flight Ops department, which uses air force ranks – translated British-style), but doesn’t use naval command structure (see here). And the IN’s ship’s troops aren’t marines, because the Empire doesn’t have a separate service for such; they’re just that portion of the Imperial Legions that happens to serve on starships, and as such, they’re still just called “legionaries”.
The Bridge is always located as close to the center of the vessel as possible, with the only proviso being the need to keep it a decent distance from the backup bridges. And has no windows. Only an idiot puts their bridge somewhere it’s likely to get shot off.
And since most military vessels are in inertially-damped microgravity, internally, the decks are in whatever layout is most convenient, whether tail-lander, belly-lander, or more outré, with no particular need to match each other, never mind a consistent orientation to the direction of flight. Likewise, there is no distinction between “top”, “bottom”, or indeed “sides” on anything that doesn’t do planet landings – shipboard directions such as “port”, “starboard”, “dorsal” and “ventral” are defined by angle around the thrust axis – and indeed, radial symmetry is probably more common than bilateral in ship designs.
While there are some (artificially engineered) Space Whales, space is definitely not chock full of them. And there is also a distinct shortage of Negative Space Wedgies like ion storms, etc., hanging around. Mostly, space is full of empty. That’s why it’s called space.