"Tonnage" is irrelevant for starships that can move at the speed of light on a whim, so that's a non-starter. Also, the only people who ever referred to the Enterprise as a "battle cruiser" were the Klingons, who also referred to the Genesis Device as a "doomsday weapon" and referred to Kirk as "the Genesis Commander." Kruge and his crew were able warriors, but they got a D-minus in "knowing what the hell we're talking about." To be sure: the designation "heavy cruiser" doesn't tell you much of anything since we don't know what the OTHER designations for the fleet are in context. In the Star Wars universe, for example, "cruiser" is one of the smallest ships in any given fleet and is so designated because it is a high-efficiency starship that can move quickly from one place to another without having to stop and refuel and without needing support from a major shipyard when it gets where it's going. Starfleet may use similar designations, with larger "exploration cruisers" having additional heft by being able to travel long distances and ALSO carry a fleet of shuttlecraft and a massive science payload that would allow the cruiser to quickly map and survey the entire surface of a newly discovered planet (where the smaller cruisers would be limited to point surveys of landing sites maybe half a mile across). Try to remember that Starfleet's primary construction priority is science and exploration. Their starships are VERY apt combatants, but that's not what Starfleet built them to do and is not their primary reason to exist. A Federation starship is first and foremost an exploration and research vessel that can and will kick your ass up and down the milky way if you don't play nice and let them get on with their important scientific research (as I've said many times: you can kill a man with a scalpel, but you can't perform surgery with a battle axe).[/quote] No, a "Dreadnaught" would be so defined by having an extremely heavy weapons complement plus a ridiculous amount of armor (or in this case shielding), thus defining a vessel whose primary function is that of a slow moving but virtually indestructible weapons platform. Ironically, the Death Star is probably the ultimate example of this design philosophy: it's not fast, it's not maneuverable, but it doesn't really matter because anything that comes into its firing range is gonna have a bad time. Starfleet doesn't build ships that can only lumber up to an opponent and pummel it to death. They DO build ships that can analyze the hell out of something, and their largest ships can do this far better and more thoroughly than smaller ones. At the same time, the enormity of the Enterprise's warp nacelles (proportionately larger than any starship we've ever seen) also suggests these big ships are built for speed, which might also explain their hugeness: it HAS to be that big just to house the gargantuan powerplants needed for ultra-fast warp drive. Neither "battleships" nor "destroyers" canonically exist in Star Trek. But again, the lack of those smaller ships probably implies that a tiny vessel the size of the Constitution class just doesn't have the power available to move that quickly without also blowing itself to smithereens. That's not to say they CAN'T move that fast (TOS Enterprise sometimes did) it's just the "smithereens" part makes that undesirable. That is quite literally the OPPOSITE of how that works in 3D modeling, but go ahead and keep repeating it as if it makes your point more relevant. It makes perfect sense to me, considering absolutely NOTHING in the original universe precludes the existence of ships the size of Kelvin or even the Enterprise. All the more so when you consider that if you knew nothing about Star Trek except for the first three reasons of Voyager, the existence of the Enterprise-D would seem like a huge incongruity.