The "three Hs" are history, hiding, and hydrodynamics. For the first H, history, there were only two two types of warships: "battleships" and "scouts and auxiliaries." They usually didn't call them by these names, but that's a good functional description. The battleships fought, and the scouts and auxiliaries scouted and carried troops, materiel, messages, and the like. In the 20th century, though, we got changes: new weapons (torpedoes) that make a new type of ship, the escort, necessary, and new platforms (submarines and airplanes) that used the new weapon (and added aerial bombs). These new weapons had the frightening ability to, at least on paper, kill a battleship with a single blow. And one warfare area (surface combat) becomes three -- surface, subsurface, and air. That's historically how things developed, with different time periods having their own particular characters, as new technologies were developed and old ways of doing things were superseded. Science fiction navies, however, are often a mishmash of time periods, with all of the "cool bits" mixed together. So, they don't make sense given the assumptions of the fictional universe or the non-fictional universe from which they were drawn.
For the second H, hiding, surface ships hide in four different ways: Behind the curve of the earth, behind the ocean interface where ocean surface meets the sky, by taking advantage of distance, and through the use of low-observability such as stealth technology. But in space, there is no curve of the earth or ocean interface to hide you from enemy radar, or even telescopes.
The third H is hydrodynamics: For a ship in the water, drag increases as the cube of speed. This is why ships have a top speed. As your speed increases, your drag increases exponentially, until you double the size of your engines but you really don't go any faster. In space, your top speed is more about reaction mass, but you have other issues that have to do with how big a ship you can build before it starts to collapse in on itself. As ships grow bigger, they have to devote a greater percentage of their total mass to holding themselves together. Hydrodynamics limits and defines surface ships and submarines, just as aerodynamics limits and defines airplanes. In the real world, this means that combat craft either go fairly slow like ships or go fairly fast (like airplanes -- there's not much in between. You see similar patterns in a lot of science fiction, even though they should be thinking in terms of acceleration over time, rather than top speed. As with most of these things, written science fiction is better than video formats.