The Terran Protectorate Stellar Navy deploys a heavy assault task force for assets deep within enemy territory that needs to be destroyed; not captured, liberated, or otherwise preserved. Enemy shipyards, listening posts, anchorages, staging grounds and space-based or even planet-based production facilities are all potential targets. The task force plunges into enemy territory at faster-than-light speeds, come out as close to the target as possible, put as much firepower onto target as possible, ensure its destruction, and then retreat back to the Protectorate. They hit fast, and very very hard, and they are meant to hit where it hurts. A standard H.A.T. consists of three battleships or battle cruisers, usually with a Dreadnought class battleship or Hastings class battlecarrier as the flagship, and either a pair of Powell class battleships or Damocles-class battlecruisers. They are escorted by four heavy cruisers, six to ten destroyers and two escort carriers. The flagship carries at least a wing of fighters, mostly strike fighters like the Super Crossbow or the Ballista, while the escort carriers carry mostly interceptors like the Crossbow or the Tengu to play a defensive role. The carriers also have several light pinnaces for picket duty which are deployed once the fleet is inside enemy territory as an early warning net. The task force has the firepower to engage most enemy ships they encounter, with the possible exception of an enemy carrier fleet, which could overwhelm it with fighters while staying safely out of range of the taskforce's heavy guns. In those situations the H.A.T. tries to either quickly close or fight its way free of the fighter swarm and escape with its negative mass drives into FTL.
Using gravity technology (the handwavium of this tech) the ship is surrounded by two fields. The exterior is a Higgs-Boson Inversion Field that gives anything inside the field negative mass by shunting that mass into m-space (see m theory or super string theory). Any object with zero mass, like a photon, instantly travels at the speed of light. An object with negative mass goes FTL at speeds equal to its negative mass quotient. So a ship able to generate a 365 negative mass field goes about 1 light year per day (this universe's standard military speed, equal to warp 6 in star trek). Since ships could only really do 1 negative mass this way, the rest is actually energy. The more energy, the more negative mass you can produce. What is cool is that you start generating negative energy since with e=mc2, if m is negative, so is e. the second shield is inside the bubble and isolates the ship and its inhabitants form the negative mass shield. The downside is no time dilation, so a 5lightyear trip at 365C actually takes five days to those inside the ship. Withou the interior field, the trip would feel instantaneous, but you would also disintegrate due to the NM field or be liquified by the nearly instant deceleration and acceleration if you did not have it.
My high school was an aerospace technical school for wannabe engineers. Even though I went into journalism, I still sometimes think that way about technology, and I also flirted with being an astronomer/astrophysicist but realized that while I am good at math, it bores me to tears and that's most of what they do.