Honorverse spacecraft move around using a reactionless "impeller drive" based on gravity manipulation. This drive can accelerate craft at thousands or even tens of thousands of thousands of gravities in the case of impeller missiles.
Crewed ships also have "inertial compensators" which protect the crew from the acceleration, and these have a limit on how much acceleration they can handle before failing. This limits crewed spacecraft to accelerations in the hundreds of gravities.
When I think about it though, this doesn't make sense. If the impeller drive is creating a gravitational field which causes the ship to fall forward, then there's nothing to protect against as all of the matter in a member of the crew will be falling at the same rate, and at the same rate as the ship.
If the impeller drive is not doing that but is, for instance only accelerating the drive system which then transfers the force to the rest of the ship, and the crew, mechanically, then the drive should destroy the ship just as readily as the crew when enough force to accelerate it at 300g is transmitted through it.
Physics and material engineering aren't my areas of expertise, but it seems like every single component of a missile would have to be made of something like the Scrith of Ringworld that transcends the properties of what we know matter to be rather than just being advanced nanotechnological materials as described in the books.
A force field that can exert balancing forces on the drive system and the rest of the ship to even out the force would resolve this, and so, make sense as an "inertial compensator" but then missiles would need the same compensators, and ships that suffered compensator failures would be destroyed rather than killing their crew while remaining intact.
Has this ever been addressed either in the text or in a pronouncement from David Weber? Am I underestimating the strength that is possible for nanotech materials?