Jame asked,
After four pages, I forget if I asked this: what role does each type of ship do in each type of fleet, if fighters are ignored.
What would a battleship, its battle cruisers/heavy cruisers, light cruisers and escorts do in a strike fleet? What tactics do it use?
Same for a patrol group and an assault group?
Basically, ships fight their own size and one size smaller enemies, plus bigger enemies if they have to or wind up being the biggest in the group.
So, a full battlegroup with battleships (BB) uses those BB for the serious firepower, to kill enemy BB and cruisers (CR). The battlegroup CR are used to kill enemy CR and destroyers (DD), and they snipe at enemy BB when they think they can get away with it. DD and other escorts kill each other and fighters (VF), plus (IMTU) using their defenses to thicken the defenses of the bigger ships (especially CR, which need the help more). DD usually don't bother shooting at BB since they can't penetrate their defenses, but they might try ganging up on an isolated CR. In the OTU, VF pretty much just shoot each other, there's nothing else they can hurt except maybe a DD.
In a raiding group built around a CR squadron, the CR play the role of the BB in a battlegroup: they fight everything bigger (although they'll usually try to run from anything bigger if they possibly can) and act as the big guns against everything else. DD and VF play their same roles.
In a patrol or escort group built around some DD, the DD are the biggest boys and they have to do it all, although VF are more useful here since often the worst opposition expected are enemy DD and some pirate/privateer ships. VF are very useful against such ships, or to keep the freighters rounded up.
In any kind of group, carriers (CV) play mothership and usually keep out of harm's way, sending in the "detachable turrets" (their fighters) to do the dirty work. Some CV are strike carriers, armed and armored like CR and so capable of acting like CR if needed.
Tactics: BB and CR with meson guns or spinal particle accelerators want to get close so they can do more damage, but they want to do it without taking so much damage on the way in that their spinal mounts are useless.
So the battle usually begins with a missile duel at long range as each side tries to reduce the firepower of the other's spinal mounts to a level where they're not too dangerous and you can accept the losses they'll inflict at close range.
It's difficult to win outright at long range since it's easier for ships to withdraw and missile fire slowly wears big ships down, it doesn't wipe them out in a "one-shot-zot" as a spinal meson gun does.
Close range battle with effective meson guns on both sides is mutual suicide, "submachineguns at ten paces" as David Weber puts a similar situation in the Starfire books. The side with more meson guns left will usually win, but it's going to be bloody.
If one side has meson guns and the other doesn't, the side without wants to keep it at long range and just keep pounding with missiles at least until those meson guns are out of action.