Bit of Analysis: Honor Harrington III

[Simon_Jester]

In addition to what Simon said about 12 hits of a Dreadnought kill, those twelve hits all came at once, down the throat of the ship right? That's like the ideal situation for the attacker. The combination of concentration, raking fire down the length of the ship and lack of sidewalls is giving those opportunity to give those missiles maximum damage for their bang.

Well, dreadnoughts are supposed to have heavy armor on the hammerheads and if the design is sane, they should have hundreds of meters of defensive depth between the bow of the ship and anything that could possibly result in a catastrophic kill if breached.

Some of that should be internal armor, to boot.

I can buy that raking fire 'down the throat' is highly likely to penetrate the entire forward hammerhead, and probably hit the forward impellers to cause crippling damage to the ship (knocking it out of formation, in many cases). But the fusion plants should be farther back, and if laser heads can penetrate THAT far then they should be blowing right through capital ships and out the other side.

In which case, if nothing else, it shouldn't really matter very much which side you take a hit on; the starboard weapons are about as likely to be put out of commission by a hit from the port side as the port weapons are.

Speaking of that: sometimes there are sidewall generators mentioned and sometimes impeller ring damage seems to do nasty things to sidewall strength. Are the two systems supposed to be interlinked ?

Yes. There's no way to generate a sidewall without a wedge (at least, not a useful sidewall for a mobile starship), so it stands to reason that disruption of the wedge-generating mechanism could have side effects on the sidewalls.

Since A238 said this is essentially on hold for a while I'd like to continue with trying to find out the likely results of compensator failure.

Another possibility is that damage to the ship's electronics might cause some but not all of the drive nodes to abruptly stop functioning. This could act to throw the impeller wedge out of balance and possibly result in turning, changes of acceleration, or more chaotic motion like tumbling.

Yeah; the failure modes for such a stupidly energetic reaction drive are more likely to blow up the ship (or parts thereof) than they are to produce much usable thrust. I'd be more concerned about malfunctions in the impeller wedge system itself. Sort of like how if a plane loses control input with the engines still running, it can fly straight and level... but if one of the engines then fails, that plane is going into a corkscrew sooner or later.

We already know beta node losses will downgrade their acceleration so changes in that are a given. But I don't remember ever seeing a ship changing course due to node failure. The closest we ever get is 'veered out of formation' which is inevitable if your acceleration drops/ceases. At no point to we see node loss resulting a ship developing a tendency to pitch/yaw that needs to be compensated for.
It's always about acceleration.

That's true but honestly surprises me. Quasi-realistic physics suggests that an unbalanced engine system should cause asymmetry and tumbling.

Under normal conditions there would be failsafes which might rapidly adjust the wedge to counter for any unwanted maneuvers (say, by abruptly cutting power to one of the nodes opposite the damaged one, then gradually bringing back power after they figure out how to balance things out).

But after a compensator failure this would not be the case.

I actually hadn't thought about Bean's idea of the ship post-failure executing preprogrammed maneuvers but while that's possible it would require really unfortunate timing to become a problem. It would require for the failure to happen seconds before the ship received and acted on that 'belay the course change/change the course to XYZ' order with little to no margin of error left in case the ship is slow on the helm. Given the rather sedate pace at which Honorverse ships change heading I find that somewhat dubious.

Another possibility is that compensator failures are actively more likely during a turning maneuver than they are during straight-line flight. Which is perfectly credible, since turning results in a more complicated relationship between the forces acting on the ship, the ship's own inertia, and the geometry of the wedge.

[Batman]

I'm not sure the terms 'quasi-realistic physics' and 'engine system' belong in the same sentence when the engine system under discussion is impeller drive.

[Simon_Jester]

Well, we know the impellers are machines that work in tandem, operating in 'rings' of nodes. We know they have to somehow exert some kind of physical force on the ship; they may be a reactionless drive but the ships at least more or less follows Newtonian laws of inertia, momentum, and acceleration. We know that things like "wedge torque" are real concepts in published, canon material in the series.

It really isn't that big of a stretch to posit that an unbalanced impeller wedge could cause a ship to enter an unpredictable turn, if that ship does not have the benefit of efficient safeguards to cut the turn short before it becomes too large. Noting that with impeller drive this doesn't require fast reactions because the turns are slow.

[Batman]

Except that never ever seems to happen.

[Simon_Jester]

We've only seen a very limited number of cases where it could have happened, because wedge damage inflicted while there are still functioning computers and crew would be relatively easy to counteract, due to how slowly impeller-drive ships maneuver.

So while we can be sure it's not a routine occurrence, I don't think we can rule it out... although this is exactly the sort of thing I *WISH* Weber would infodump on.

[Batman]

Define 'very limited'. Every single time a ship suffers compensator failure, she doesn't change course, she just either starts coasting or continues accelerating at the pre-failure rate.

[Simon_Jester]

How many instances is that? I'm sure it's more than the two I'm aware of.

[Crazedwraith]

In addition to what Simon said about 12 hits of a Dreadnought kill, those twelve hits all came at once, down the throat of the ship right? That's like the ideal situation for the attacker. The combination of concentration, raking fire down the length of the ship and lack of sidewalls is giving those opportunity to give those missiles maximum damage for their bang.

Well, dreadnoughts are supposed to have heavy armor on the hammerheads and if the design is sane, they should have hundreds of meters of defensive depth between the bow of the ship and anything that could possibly result in a catastrophic kill if breached.

Some of that should be internal armor, to boot.

I can buy that raking fire 'down the throat' is highly likely to penetrate the entire forward hammerhead, and probably hit the forward impellers to cause crippling damage to the ship (knocking it out of formation, in many cases). But the fusion plants should be farther back, and if laser heads can penetrate THAT far then they should be blowing right through capital ships and out the other side.

In which case, if nothing else, it shouldn't really matter very much which side you take a hit on; the starboard weapons are about as likely to be put out of commission by a hit from the port side as the port weapons are.

That's a fair point I was mostly thinking about why Raking fire the tactic in Napoleonic times. In Honorverse is mostly about the no sidewalls getting the way but still.

Speaking of that: sometimes there are sidewall generators mentioned and sometimes impeller ring damage seems to do nasty things to sidewall strength. Are the two systems supposed to be interlinked ?

Yes. There's no way to generate a sidewall without a wedge (at least, not a useful sidewall for a mobile starship), so it stands to reason that disruption of the wedge-generating mechanism could have side effects on the sidewalls.

The Reason I was asking was I wasn't sure that Honorverse was particular consistent about it. I'm sure in early books stations and things were said to have 'spherical sidewalls'. That I assumed to mean that all directions were covered by a sidewall and there was no wedge.

Likewise in Honor Of The Queen, they damage to impellers that kills their acceleration but I don't recall this ever affecting their sidewalls. The big problem then was the sidewall generators getting shot out and the sidewall strength going down because they were coving a great area with the remaining generators.

[SpottedKitty]

I'm sure in early books stations and things were said to have 'spherical sidewalls'. That I assumed to mean that all directions were covered by a sidewall and there was no wedge.

IIRC the reason for that was the spherical sidewall meant you couldn't put up a wedge — no wedge, no accelleration. That's why stations, and the Junction forts, used spherical sidewalls, they didn't need to move unless they were being redeployed.

[Simon_Jester]

That's a fair point I was mostly thinking about why Raking fire the tactic in Napoleonic times. In Honorverse is mostly about the no sidewalls getting the way but still.

Raking fire worked in Napoleonic naval combat because:
1) The structural members of a wooden sailing ship come together at the bow, so damage to the bow can indirectly affect the structural rigidity of the ship in ways it would not affect a cylindrical hull.
2) The interior of a wooden sailing ship has relatively light internal partitions and cofferdamming

Yes. There's no way to generate a sidewall without a wedge (at least, not a useful sidewall for a mobile starship), so it stands to reason that disruption of the wedge-generating mechanism could have side effects on the sidewalls.

The Reason I was asking was I wasn't sure that Honorverse was particular consistent about it. I'm sure in early books stations and things were said to have 'spherical sidewalls'. That I assumed to mean that all directions were covered by a sidewall and there was no wedge.

Likewise in Honor Of The Queen, they damage to impellers that kills their acceleration but I don't recall this ever affecting their sidewalls. The big problem then was the sidewall generators getting shot out and the sidewall strength going down because they were coving a great area with the remaining generators.

They are consistent. Spherical 'bubble' sidewalls exist, but the generating machinery is bulky and redundant and to the best of my knowledge is never used on a highly mobile ship. It is used on "forts" that are essentially very big sublight superdreadnoughts with stupidly low acceleration (say, 10-16 million tons).

My point is that normally yes, it is possible to damage the impellers without losing sidewall coverage, and to lose sidewall coverage without damaging the wedge. But while that's true, it doesn't automatically mean that damage to the wedge never affects the sidewalls. Or that the term "wedge" is never used to refer to the entire assembly of impeller-bands-plus-sidewalls that surrounds and shields the ship.

[VhenRa]

Actually. From memory, in On Basilisk Station... the smallest of Manticore's junction forts are 16 MT.

[Simon_Jester]

I thought that was an upper limit.

[Terralthra]

I thought that was an upper limit.

Negative. "The smallest of which massed twice as much as a superdreadnought" is the phrase I remember.

[SpottedKitty]

I thought that was an upper limit.

I don't think there is an upper limit to the size of these things, beyond "how many more bits can we bolt on?" — they're not intended to ever need to zoom off at high speed, so they're not bound by the current mass limits on node/impeller/compensator performance, like a top-end superdreadnought.

[Simon_Jester]

Well, there is some mass at which if you fire up a ship's impeller drive it won't move, which represents an effective upper limit if it's intended to have impellers at all, if only for low-acceleration maneuvers.

[White Haven]

Remember where the Junction is. Specifically, it's in Manticore, which has a couple of massive shipyards in-system, which each have a cadre of heavy tugs. Were I building defenses for such a place I'd be quite happy to outsource 'how do we move this thing' to tugs and make my fortresses nothing but piles of energy mounts, missile launchers, magazines, fire-control installations, point-defense mounts, and the like.

And armour. Lots and lots of fucking armour, since all of a sudden mass doesn't matter, but ability to survive a surprise maximum-mass junction transit attack at least long enough to return fire really, really does.

[Terralthra]

Nah, Weber is clear that the fortresses have wedges and can move independently. Not very fast by Honorverse standards (sub 100g), but they can.

[White Haven]

Hmm, I must have missed that part. Not the choice I would have made in-verse, but there it is.

[Simon_Jester]

Remember where the Junction is. Specifically, it's in Manticore, which has a couple of massive shipyards in-system, which each have a cadre of heavy tugs. Were I building defenses for such a place I'd be quite happy to outsource 'how do we move this thing' to tugs and make my fortresses nothing but piles of energy mounts, missile launchers, magazines, fire-control installations, point-defense mounts, and the like.

And armour. Lots and lots of fucking armour, since all of a sudden mass doesn't matter, but ability to survive a surprise maximum-mass junction transit attack at least long enough to return fire really, really does.

Arguably so. Then again, the impeller wedge is not just desirable because it allows mobility; it's also a protective feature. Honorverse capital ships only have to armor roughly half their surface area against incoming fire because the wedge geometry prevents hits from any other angle, for instance- and you might actually save tonnage and cost by using impeller bands to provide that coverage. It may be more cost-effective to include an impeller wedge even if the thing doesn't go anywhere.

Plus, the impeller wedge's dorsal and ventral bands are the only known impenetrable defense. That could matter in some situations- the idea that your fort has an absolutely impenetrable defense, or can physically interpose itself between incoming fire and a target and know that this fire won't pass.

[White Haven]

Given that the forts generally use spherical sidewalls most of the time, that spherical sidewalls are incompatible with wedges, and that it takes minutes at best to spin up an impeller wedge on a normal warship, I doubt 'switch to wedge!' is going to be a valid defensive tactic mid-engagement, not at the knife-fight ranges that the forts have to be prepared to operate at.

[Simon_Jester]

Yes, but in other situations things are a bit different- say, if you're worried about hypervelocity ballistic impactors screaming in at you from a particular direction.

[VhenRa]

Technically, if were to limit yourself to 1G... you don't need an inertial comp. Hell, if you were to limit yourself to whatever grav plates can handle, you don't need one. The limitation on wedge propelled craft is inertial comps, not the wedge itself. The interesting thing, if you place the Forts what? A million or so KMs out from the junction, you are able to rake them with energy fire while they can't reply. Remember, energy range is 500 million KM against a side-wall, ships come through the junction without one and thus that is doubled. And if you place your Forts correctly, you are also going to get down the throat vectors.

[Batman]

Um-500 million km is roughly 10 times upper-end MDM range (at least before Apollo). Energy range is about a lightsecond. Not to mention that at 500 million km, a lightspeed weapon discharge would need nearly 28 minutes to reach the target. You better be really good ad predicting where the target is going to be nearly half an hour from you firing to make that work.

[Mr Bean]

I believe VhrenRa meant 500,000 as in five hundred thousand not five hundred million.

[VhenRa]

I believe VhrenRa meant 500,000 as in five hundred thousand not five hundred million.

Yeah... I did. -Facepalm-

I be fail at math, that isn't usual for me. Yeah, I meant 500k KMs being energy range. Its also stated energy range without a sidewall... is a million KMs. So park your Forts out around a million KMs... and you are within energy range and with your spherical sidewall, they aren't. And gun them down as they exit the wormhole, without sidewalls.