pd 1924 - Shape of Beowulf's fleet

Relax wrote:

Jonathan_S wrote: You want a spherical sidewall because, even with bow walls, there are still large chinks in the armor of impeller + sidewalls (because we're told physics says you can't close the bow and stern stress bands simultaneously -- so you have to leave one end unprotected).

I had the impression that even in combat they aren't under impeller most of the time -- that's just for if they have to reposition, say to spread out to cover gaps where another fort was destroyed, or to dodge frac-c ballistic attacks.
But if under impeller say the fort chose to leave it's stern open (as that opening is smaller) - an missile passing behind it within +/- 3.84 to 3.87° horizontally and +/- 7.56 to 7.63° vertically of it's current long axis has a shot on some of the ship unprotected by any sidewall (narrower ranges means LOS all the way to the bow, wider only gives LOS to the stern).

That's not vast, but it's way bigger than the zero vulnerable angles a spherical sidewall gives you.

But why have the ends open at all? You are outside the hyperlimit. There is zero reason to only run a buckler(allows acceleration) May as well have a massive bow/stern wall.

Only fly in the ointment is we do not know the actual STRENGTH of a spherical sidewall and how much mass/power it requires compared to SDP bow/stern/sidewalls or equivalent sidewall strength as spherical. It could be, massively(pardon the pun) in favor of spherical. If so, can still use hyper generator etc to get to the other systems.

Where is the 10X slower coming from? 600G vrs 150G is 4X. I thought new grav plates 150G = 1 G instead of the 75G shown in books previously and it was only when pushed beyond this that another ~75G = 5G apparent when talking about the MALIGN Sharks? Hrmm, Mission of Honor?

Oh well, gotta go, dinner and not sure I will be able to reply much. Busy, but wanted to relax some and peruse the forum.

You leave (at least) one end open because (as I said in the first sentence of that quote) the author said you couldn't simultaneously close them both.
["Ashes of Victory"]the physics of the wedge meant only one aspect, bow or stern, could be closed at any given moment, but it gave a Ferret's skipper a much more flexible choice of breakaway vectors.[/quote]

So even if you don't want to accelerate a spherical sidewall gives full protection in a way that side + bow wall can't. OTOH the wedge + all available 'walls does provide sensor blocking and invulnerability from two directions in a way the spherical wall can't provide at all.

(FWIW even if you can combine a stern buckler with a full bow wall -- which I can't find any statements about in the books -- the bucker, based on the descriptions, only seems to protect against fire from a very narrow angle; virtually just from dead astern. so it doesn't shrink the size of the aft vulnerable zone by all that much. Useful in a one on one energy fight, and better than nothing if you have to do a straight pursuit, but like the physical shield it was named for it'd take skill to defend yourself with such a small protection)

And the ~10x faster is how much faster a ship (with compensators) can accelerate under sail than it can under impeller. Pushing the Invictus's accel from a normal space 613.3g to a sail-powered nearly 6,133g
Taking the actual acceleration difference between it and something still limited to 150g on grav plates from 4x to 40x.

That acceleration while under sail in a grav wave comes from SVW's Universe of Honor Harrington appendix [quote="Short Victorious War"]One might expect admirals to avoid grav waves if forced to fight in hyper, but doing so is tantamount to breaking off the action. The reason is simple: a ship under Warshawski sail can pull almost ten times the acceleration it could under impeller drive.[quote]

Jonathan_S wrote: You want a spherical sidewall because, even with bow walls, there are still large chinks in the armor of impeller + sidewalls (because we're told physics says you can't close the bow and stern stress bands simultaneously -- so you have to leave one end unprotected).

Jonathan_S wrote: You leave (at least) one end open because (as I said in the first sentence of that quote) the author said you couldn't simultaneously close them both.

And the ~10x faster is how much faster a ship (with compensators) can accelerate under sail than it can under impeller. Pushing the Invictus's accel from a normal space 613.3g to a sail-powered nearly 6,133g
Taking the actual acceleration difference between it and something still limited to 150g on grav plates from 4x to 40x.

That acceleration while under sail in a grav wave comes from SVW's Universe of Honor Harrington appendix [quote="Short

Thx, In reverse: If forts can have impellers(hull form), capability for Warshawki Sails seems implicit. No reason they couldn't if they can have impellers. Should also have the 10X in a grav wave and compensators.

As for bow/stern and only ~1 end closed... that was due to power limitations on the LAC class IIRC. Not a limitation of bow/sternwalls in general. Maybe SoSAG or SftS would have those details with introduction of late SAG-B, SAG-C designs

Relax wrote:Thx, In reverse: If forts can have impellers(hull form), capability for Warshawki Sails seems implicit. No reason they couldn't if they can have impellers. Should also have the 10X in a grav wave and compensators.

As for bow/stern and only ~1 end closed... that was due to power limitations on the LAC class IIRC. Not a limitation of bow/sternwalls in general. Maybe SoSAG or SftS would have those details with introduction of late SAG-B, SAG-C designs

Again the fort will NOT have a compensator, because of the mass limit. It also seems that the bigger the ship, the bigger the hyper-generator must be; which the normal fort omits to include more weaponry.

It is true that a LAC does not have enough power to put a wall in one aspect and a buckler in the other, but it is still the case that the author stated that no one can have both a bow and a stern wall at the same time: From Ashes of Victory chapter 24:

Accordingly, BuShips had used the last scraps of the internal volume freed by removing the graser to shoehorn in an additional sidewall generator. Just as powerful as the new "bow-wall" that closed off and protected the front of a Shrike's wedge as it bored into energy range, the Ferret's "sternwall" closed off the rear of the wedge. Power requirements and the physics of the wedge meant only one aspect, bow or stern, could be closed at any given moment, but it gave a Ferret's skipper a much more flexible choice of breakaway vectors.

PS: Jonathan_S already gave you this quote; the "physics of the wedge" is NOT dependent on the "power requirements".

Relax wrote:In reverse: If forts can have impellers(hull form), capability for Warshawki Sails seems implicit. No reason they couldn't if they can have impellers. Should also have the 10X in a grav wave and compensators.

As for bow/stern and only ~1 end closed... that was due to power limitations on the LAC class IIRC. Not a limitation of bow/sternwalls in general. Maybe SoSAG or SftS would have those details with introduction of late SAG-B, SAG-C designs

The quote says physics. (Okay, the full quote, which tlb provided, says power and physics -- but there's been no indication that the physics changes even on ships with bigger power plants). So I still believe that it's not possible to have a full bow-wall and full stern-wall up simultaneously.



As for the hull form, beta nodes don't impose hull form limits (otherwise a pinnace with its variable sweep wings and vertical tail couldn't have an impeller -- but it does. Based on the drawings in Jaynes it has a single aft-mounted beta ring; right behind the air breathing engine nacelles[1] and just before the cruciform angled tails.

It's the need to use alpha nodes to create a sail that seems to force the double-tapered spindle hull form. So no sails means more freedom of hull shape.

Still the issue for getting the extra 10x accel in a grav wave isn't mounting impellers, or even a sail. It's the benefit the compensator gets from the much stronger natural gravitational sump the sail's interaction with the wave provides (compared to the shallower artificial sump of an impeller wedge).

On Basilisk Station wrote:the compensator's efficiency depended on two factors: the area enclosed in its field and the strength of the grav wave serving as its sump. Thus a smaller ship, with a smaller compensator field area, could sustain a higher acceleration from a given wave strength, and the naturally-occurring and vastly more powerful grav waves of hyper-space allowed for far higher accelerations under Warshawski sail than could possibly be achieved under impeller drive in normal-space.

Grav plates would get no such benefit as they don't use an external gravity sump; so grav plates wouldn't get an accel boost simply because you're in a grav wave. If your ship is too large to use a compensator then sails would let it safely navigate a grav wave -- but with the exact same grav plate limited accel it has anywhere else. (And a 10x boost wouldn't be enough to make a compensator useful if the ship size was much beyond the edge of the "compensator "plateau".

More Than Honor wrote:Note also that in 1900 pd, 8,500,000 tons represented the edge of a plateau in inertial compensator capability. Above 8,500,000 tons, warship accelerations fell off by approximately 1 g per 2,500 tons, so that a warship of 8,502,500 tons would have a maximum acceleration of 419 g and a warship of 9,547,500 tons would have a maximum acceleration of 1 g.

Better compensators might have shifted the slope as well as the max ship size [which seems to have gone up about 3.3%] but even so my best guesstimate is by the time you hit 10.2 mtons you'd be down to 15g under impeller and 150g under sail; at which point why even bother installing a compensator.


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[1] The M28 Condor-class pinnace has engine pod that are vaguely business jet or MD-80 looking -- being pods off the side of the fuselage. Except they're more forward, positioned atop the (low mounted) wing root and thus also have to sit higher.

Jonathan_S wrote:As for the hull form, beta nodes don't impose hull form limits (otherwise a pinnace with its variable sweep wings and vertical tail couldn't have an impeller -- but it does. Based on the drawings in Jaynes it has a single aft-mounted beta ring; right behind the air breathing engine nacelles[1] and just before the cruciform angled tails.

It's the need to use alpha nodes to create a sail that seems to force the double-tapered spindle hull form. So no sails means more freedom of hull shape.

I have also been saying that sails dictated the hull form; unfortunately I cannot find supporting text, but can find text saying that the impeller (wedge) does that:

From "Honor Harrington's Navy", section "NAVAL DESIGN AND DOCTRINE" in The Short Victorious War:

The constraints of the impeller drive and the fact that ships were designed for broadside fire also dictated their hull forms.

The nodes which generated the impeller wedge had to be very specifically located relative to the dimensions of a ship. In general, they had to lie within twelve to fifteen percent of the extreme ends of the vessel and well inside the maximum beam which the wedge allowed. Although there were a few idiosyncratic exceptions, this meant virtually all warships were flattened, "hammer-headed" spindles, tapering to their smallest dimensions at their fore and aft impeller rings and then flaring back out to perhaps a quarter of their maximum beam.

From chapter 5 of Honor Among Enemies:

That was the biggest weakness of Trojan Horse, for the Caravan class were true merchantmen—big, slow, bumbling freighters, without armor, without military-grade drives, without internal compartmentalization or a warship's sophisticated damage control remotes. Their hulls were the flattened, double-ended spindles of any impeller drive vessel, but they'd been laid out to maximize cargo-handling efficiency, without a warship's "hammer head" ends, where the hull flared back out to mount powerful chase armaments.

PS: Something like a pinnace might already be so small that there is no noticeable taper.

PPS: The constraint on the hull shape due to sails seems to be that their nodes need to be near the extreme front and back of the ship. From the author "the reason ships have two impeller rings is that it is the alpha nodes which must be placed near the ends of the hull".

Relax wrote:??? Real world is not stealth recon Short Victorious War. In war, scouting is done ALL the time; everywhere. Why there are no DD's/CL's, CA's, BC's available for commerce protection in 1st Havenite war. Those ships are scouting hoards of systems continuously. With advent of RD's this makes it absurdly easy to do, and see so called "concealed" mass deployed pods which in DW's universe are bare ass naked to EMP from missiles nuclear explosions close by( ).... so any "scouting" force in a real war, will see those mass deployed "stealthed" pods and just launch while they dip back into hyper. Pods can't hide/maneuver. Problem solved. A couple LAC squadrons sweeping asteroid fields before deploying the Fleet: Problem solved. Take your pick. Mass deployed pods have to be defended.

Your warships will usually not be welcome inside the hyperlimit of a system you're at hostilities with or with whom tensions are high. Even if the situation was a pre-hostilities scenario were everyone is pretending to be friends while sharpening their knives, foreign warship movements would be severely restricted and definitely designed to pass away from possible missile pod shoals. Any use of high-power radar would immediately be noticed. Those warships would also get a close escort which would notice a recon drone being launched, and if not then the FTL comms with the drones might be. Your hosts would ask pointed questions about this and might even intern you warship until a mediator can be found to resolve the situation. And if those drones do stumble upon something they shouldn't see and they themselves are seen, the jig is up. That might give your adversary causus belli and go to war against you before you're ready (and if you need a Monitor to take on them, they're likely a peer power).

The alternative to this is to use non-warships to do the scouting, like couriers and freighters, designed to appear inoffensive, but be loaded with military sensors. Still, the lack of active sensors and the inability to use drones to their fullest will limit what you can get. Then there's the time component of this: unless this Q-ship is still in system and transmitting real-time when the invasion force arrives, the situation "on the ground" may have changed, with shoals moved or activated, decoys emplaced, etc.

My point is that intel can be flawed for a number of reasons. Even after the active hostilities have begun, your RDs can only find things that are relatively close to them. The longer your hypergenerator recharge time is, the bigger the volume where dangerous shoals will be too. And of course, the most critical time is shortly after you've arrived, when your RDs have not yet scouted the entire system.

Therefore, it behooves a strategian not to be inflexible. Bigger ships reduce flexibility. So you had better be sure that you won't lose your über-capital ships because they couldn't escape a trap because the hypergenerators were still cycling.

Why I have argued here and many years previously your fleet reaction unit should 100% be outside the hyperlimit, where the repair base which should be as deep into the star's gravity well as possible. ~Backside of Mercury in perpetual darkness and your main fleet port stationed near the hyperlimit surrounded by large continuously powered blocking wedge forts, with spacing just big enough to not allow Missiles fired from outside the hyperlimit inside, but tugged, slow, ships could be brought in through a revolving impeller wedge for instance.(not fully thought out, but hey, food for splatter on a chalk board and maybe some thought)

I am in complete agreement that fighting from 10 light-minutes away, from outside the hyperlimit, is the way to go now. That tactic is currently only available to the GA forces, but we should expect it to be viable to others soon-ish, even if at reduced effectiveness because they can't duplicate the Apollo missile's AI and the bandwidth of its FTL transmitter.

None of which requires a Monitor-sized ship, though.

BTW, the "backside of Mercury in perpetual darkness" is actually wrong here. Aside from the fact that it is not tidally-locked to the Sun (only resonance), the "backside" you're referring to is relative to the hyperlimit, so it's actually the side facing the Sun. So you meant the "perpetually lit" side, at something like its L1 Lagrange point. Which has the nice added benefit of having extremely cheap solar power to fuel the yards. The only drawback is that as the innermost planet in our system, it's far from the asteroid belt where most of the easily accessible material can be found. In other systems, that may be different and there may be asteroid or rubble belts in inner orbits, or maybe the planet itself has a ring system.

The fact that it is closest to the single biggest source of every material in any star system doesn't count, in the Honorverse.

Jonathan_S wrote:Which one was the "Long" manouver?

I remember the "Lee" maneuver from ToH --popping into hyper to reposition and scrub off speed. (Though that it had other problems -- at least in the eARC and I don't think they got corrected in the final version. RFC only accounted for one 92% translation bleed-off; but elsewhere says that the bleed-off happens whether going up or down; so the new velocity should have been 8% of 8% of the original; but RFC's number was 8% of the original. Which wouldn't be so much of a problem except it was an explicit plot point that the fleet still had so much velocity it couldn't stop for 36 minutes; and that plot point doesn't work so well if you use the actual double bleed-off velocity and they're able to stop in under 3)

Though that wasn't the only spot on ToH where the hyperspace translation math went wonky.

(I understand why RFC won't deal with corrections from eARC readers -- but it's annoying when you find about 20 items which most editors will miss - from hyper/velocity maths, to relationships, to timeline issues, to ship names; and sure enough they nearly all slip through into the final release)

That's the one, and the published version says "Long Manoeuvre," not "Lee." I don't know if this was a typo, RFC changed his mind, or if he deliberately did not reveal it was Long.

The problem I'm referring to was the fact that the fleet "skipped" or "skidded" on the Alpha barrier by going up and down within seconds. That's much faster than any ship could do with stand-by generator, much less a fleet containing SD elements, and we understood the hypergenerators discharge after a translation.

It might be that the reason this manoeuvre even has a name is because it's an incomplete translation. That is, you use the hypergenerators to make a hole for you to go up the Alpha band, but then abort the process at some point before it concludes and transitions the ship into Alpha, kicking you back to n-space. This would explain why the process only took seconds and why the final speed was 8%, not 0.64%: it was a single translation.

tlb wrote:It is true that a LAC does not have enough power to put a wall in one aspect and a buckler in the other, but it is still the case that the author stated that no one can have both a bow and a stern wall at the same time: From Ashes of Victory chapter 24:

Accordingly, BuShips had used the last scraps of the internal volume freed by removing the graser to shoehorn in an additional sidewall generator. Just as powerful as the new "bow-wall" that closed off and protected the front of a Shrike's wedge as it bored into energy range, the Ferret's "sternwall" closed off the rear of the wedge. Power requirements and the physics of the wedge meant only one aspect, bow or stern, could be closed at any given moment, but it gave a Ferret's skipper a much more flexible choice of breakaway vectors.

PS: Jonathan_S already gave you this quote; the "physics of the wedge" is NOT dependent on the "power requirements".

I think that's correct but incomplete: you can't have both bow and stern walls at the same time if you want to accelerate using the wedge. If you want to continue your course ballistically and you have the power budget, it should be physically possible to close both aspects with walls.

Do note that those are strong like sidewalls, not like the roof and floor of wedge itself. They can be penetrated with enough brute force, by overloading the generators. That's why ships don't often do this: flying ballistically while taking accurate missile hits is not a good idea. A spherical, bubblewall appears to be much stronger than side walls, though probably not as strong as the wedges either. It appears therefore that, if you're going to be ballistic anyway, bubblewalls are a better option than side-, stern- and bowwall closing the wedge.

ThinksMarkedly wrote:

Jonathan_S wrote:Which one was the "Long" manouver?

I remember the "Lee" maneuver from ToH --popping into hyper to reposition and scrub off speed. (Though that it had other problems -- at least in the eARC and I don't think they got corrected in the final version. RFC only accounted for one 92% translation bleed-off; but elsewhere says that the bleed-off happens whether going up or down; so the new velocity should have been 8% of 8% of the original; but RFC's number was 8% of the original. Which wouldn't be so much of a problem except it was an explicit plot point that the fleet still had so much velocity it couldn't stop for 36 minutes; and that plot point doesn't work so well if you use the actual double bleed-off velocity and they're able to stop in under 3)

Though that wasn't the only spot on ToH where the hyperspace translation math went wonky.

(I understand why RFC won't deal with corrections from eARC readers -- but it's annoying when you find about 20 items which most editors will miss - from hyper/velocity maths, to relationships, to timeline issues, to ship names; and sure enough they nearly all slip through into the final release)

That's the one, and the published version says "Long Manoeuvre," not "Lee." I don't know if this was a typo, RFC changed his mind, or if he deliberately did not reveal it was Long.

The problem I'm referring to was the fact that the fleet "skipped" or "skidded" on the Alpha barrier by going up and down within seconds. That's much faster than any ship could do with stand-by generator, much less a fleet containing SD elements, and we understood the hypergenerators discharge after a translation.

It might be that the reason this manoeuvre even has a name is because it's an incomplete translation. That is, you use the hypergenerators to make a hole for you to go up the Alpha band, but then abort the process at some point before it concludes and transitions the ship into Alpha, kicking you back to n-space. This would explain why the process only took seconds and why the final speed was 8%, not 0.64%: it was a single translation.

Maybe.

Or the hyperdrive infodump says that a hyper generator is "also on in sustained operation the entire time the ship is in hyper, but this is not necessary to keep it in hyper; it is operated in that fashion in order to maintain hyper maneuverability (the ability to transition from band to band in routine navigation (and to evade potential threats --- natural or manmade --- by band-hopping."

That sustaining operation may mean you can hop between band, including out of hyper, without the kind of delay it takes to get into hyper in the first place. (But that wouldn't explain the failure to lose enough velocity)

ThinksMarkedly wrote:I think that's correct but incomplete: you can't have both bow and stern walls at the same time if you want to accelerate using the wedge. If you want to continue your course ballistically and you have the power budget, it should be physically possible to close both aspects with walls.

Even just the bow wall (all the original Shrikes mounted) was sufficient to stop you from accelerating with the wedge.

Echoes of Honor wrote:cutting off the stress bands' n-space pocket with a closed wedge prevents you from accelerating, decelerating, or using the wedge to change heading, Ma'am," he replied. "If you want the math—?"
"No, that's all right, Lieutenant," she said. "But suppose you don't want to accelerate or decelerate? Couldn't you generate a 'bow' sidewall then?"
"Well, yes, Ma'am, I suppose you could. But if you did you'd be unable to change—"

That's why when Shrikes attacked in that book the Peeps noticed that they'd stop their acceleration just before (slowly) turning in to use their spinal graser. (It was a slow turn in because they had to use reaction thrusters because the bow wall also blocked rotational acceleration from the wedge)

That blocking accel was already a known side effect of a bow wall before the Ferret came along and introduced us to the stern wall and the info that power and physics prevented you from using both walls simultaneously.