Ship Tare Mass?

Jonathan_S wrote:

kzt wrote:It's been established that Honorverse merchant ships work just fine at hundreds of g of acceleration without compensators. It's only the crews that have issues. So yesh, they are overbuilt by several thousand times, like a 747 made of of 16" AR500 steel plate.

I think it was in "With One Stone" that a freigher (unmanned) survived 2000g without suffering structural failure.
Just mildly overbuilt </sarcasm>

fallsfromtrees wrote:

Jonathan_S wrote:I think it was in "With One Stone" that a freigher (unmanned) survived 2000g without suffering structural failure.
Just mildly overbuilt </sarcasm>

That wasn't a freighter. That was a military research ship masquerading as a freighter.

HB of CJ wrote:To try to answer the original question, probably large cargo ships in the Honorverse would be built as lightly as possible to carry the maximum amount of available cargo.

How lightly a big cargo ship could be built would be determined by the type of cargo. A cryogenic liquid atmospheric gas ship would be specifically configured differently.

A dry bulk carrier might get away with being built more lightly. A general containerized cargo ship still differently. A builder would use as little material as possible.

The driving equation must be would the "bottom" be $profitable$ for the life of the ship. Would licensing and structural requirements try to keep the cargo ships safe?

Probably. Wide open Capitalism would find the sweet spot between cost and profitability. Earning that last credit has a settling effect on profitable safe cargo ship design.

drinksmuchcoffee wrote:
You would think that lighter materials, all other things being equal, would be less expensive than heavier materials. But we don't really have any way of knowing how much. It might be once you've built the shipbuilding infrastructure it doesn't make a particularly large difference in cost to overbuild the ship. It might also be obsolete regulations and standards from the era before counter-gravity and inertial compensators became commonplace. We just don't know.

We do know that starships in the honorverse have to be the cheapest method of bulk transportation ever imagined. If it is economical to transport foodstuffs they have to not just be very cheap, but literally tens or hundreds of billions of times cheaper on a ton-kilometer basis than rail transport or container shipping in our era.

Castenea wrote:An example from modern transportation: I believe that most if not all airliners currently built have an airframe that can withstand 5G maneuvers when new. The pilots and even more so the passengers consider anything approaching 1G to be extreme though.

pnakasone wrote:

ericth wrote:IIRC Himself said long ago that the compensator parameters are set when the ship is built, and set for a fully loaded ship.
Thus the accel is always for a fully loaded ship, even if it happens to be empty.

Cargo ships rarely travel empty as they need a certain amount of cargo value just to break even.

Jonathan_S wrote:I think it was in "With One Stone" that a freigher (unmanned) survived 2000g without suffering structural failure.
Just mildly overbuilt </sarcasm>

fallsfromtrees wrote:That wasn't a freighter. That was a military research ship masquerading as a freighter.

Jonathan_S wrote:It had been a while since I read With One Stone, and I dind't recall anything about Dorado being a military research ship. I also just quickly skimmed back through it and I'm didn't see anything jump out at me about Dorado being anything more than a freighter with circuit breakers installed (to reset the impeller nodes after getting tagged by the crippler).

The Service of the Sword, With One Stone wrote:Pampas ran his fingers tiredly through his hair. He and the other two techs had been sifting through the Sun Skater data for the past twenty hours, and the skin of his face was sagging noticeably. Swofford and Jackson, in fact, had already been ordered to bed, and Pampas himself was only going to be up long enough to give his preliminary report. "Near as I can explain it, it's like a kind of heterodyning effect between the two impeller wedges," he said. "A rapid frequency shift that creates an instability surge in the victim's wedge."
"From a million klicks out?" Damana asked. "That's one hell of a stretch."
"This isn't like a grav lance," Pampas said, shaking his head. "That does actually push the wedge out far enough to knock out a sidewall. What this thing does is more subtle. It runs the attacker's wedge frequency up and down, alternating between a pair of wildly different frequencies, setting up a sort of rolling resonance. Even at a million klicks out, there's enough of an effect to throw an instability into the victim's own wedge, which manifests itself as a transient feedback through the stress bands back into the nodes. The current goes roaring through a handful of critical junction points—" He lifted a hand and dropped it back onto the table. "And as we saw, poof."
A hard-edged silence settled momentarily onto the table. "Poof," Sandler repeated. "Is it focused, or does it affect the entire spherical region around it?"
"With only the one target in this particular attack, it's hard to tell," Pampas said. "But I'd guess it's focused. There may be a spherical effect at a much closer range, but the million-klick shot has got to be aimed."
"Well, that's something, anyway," Damana said. "If we can keep to missile-duel range, we should be able to stay out of its way."
"Unless they set the things up in stealthed probes," Hauptman said darkly. "Or even in a mine field."
"That's the other thing," Pampas said, his lips puckering slightly. "If we're right about how this thing operates, it won't work against a warship."
Damana and Sandler exchanged startled glances. "You mean one of our warships?" Sandler asked.
"I mean any warship," Pampas said.
Damana was staring at Pampas as if waiting for the punchline. "You've lost me. Why not?"
"Because warships generate two different sets of stress bands, remember?" Pampas said patiently.
"Thank you for that lesson in the obvious," Damana said tartly. A bit too tartly, in Cardones's opinion; but then, Damana was tired, too. Certainly everyone here knew perfectly well that every warship generated two separate stress bands. The outer one was what kept an opponent's sensors from getting an accurate read on the inner one, because—in theory, at least—someone with an accurate read on the strength of a wedge could slip an energy weapon or sensor probe straight through. Preventing that from happening was one reason warships' impeller nodes were so powerful for their size. "So why can't it just take them down one at a time?"
"Because there's no specific frequency for a resonance to latch onto," Pampas explained. "The two wedges act like weakly coupled springs, with their frequencies in effect flowing back and forth into each other. Same reason it's impossible to scan through someone else's wedge. We—I mean the guys inside—know how the wedges flow into each other, because we've got the nodes and the equipment running them. But there's no way to figure it out from the outside."

***Snip***

"Well, then, how about trying to stop the effect?" Cardones asked hesitantly.
"How?" Pampas asked, his tone one of strained patience. "I just got finished saying we can't stop it."
"No, I mean stop what it's doing to the impellers," Cardones said. "If it's an induced current that's frying the junction points, can't we put in some extra fuses or something to bleed it off?"
"But then the—" Pampas broke off, a sudden gleam coming into his red-rimmed eyes. "The wedge would come down anyway," he continued in a newly thoughtful voice. "But then all it would take would be putting in a new batch of fuses instead of trying to cut out and wire in a complete set of junction points."
"Couldn't you even use self-resetting breakers instead?" Damana suggested. "That way you wouldn't need to replace anything at all."
"And your wedge would be ready to go back up as soon as the breakers cooled," Pampas agreed, nodding slowly. "Probably somewhere in the thirty-second to five-minute range."

***Snip***

"Dorado acknowledging," Captain McLeod growled, cutting off the com with the heel of his hand. "You heard the Fearless, Lieutenant. Pull us back a few gees."
Hauptman, at the helm, glanced around at Sandler. "Go ahead," the real master of the Dorado confirmed for her, and it seemed to Cardones that McLeod's thin, dyspeptic face went a little thinner. It was bad enough, he reflected, to have had your ship commandeered by a bunch of hotshot ONI types barely twelve hours before departure.
But to have it commandeered by lunatics who had calmly announced their intention of ripping up and rearranging its guts in flight was even worse. The average merchie captain would probably have gone into hysterics at the very thought, or else fled to his cabin and the nearest available bottle. McLeod, former first officer of one of Her Majesty's destroyers, was made of tougher stuff.
Maybe he'd go find that bottle when he learned exactly what it was they were planning to rip up.

Sandler waited until the convoy was in hyper-space before turning Pampas, Swofford, and Jackson loose on the nodes. McLeod, to Cardones's mild surprise and quiet admiration, not only didn't come unglued, but even insisted on squeezing his way into the impeller room, dangerous high voltages and all, to watch them work.
Working on a ship's impeller nodes in flight was roughly equivalent to rebuilding a ground car engine while running a steeplechase. Sandler readily admitted she couldn't remember another case of anyone doing such a thing, but also pointed out that that alone didn't mean anything. Besides, as she reminded Captain McLeod roughly twice a day, surgeons routinely worked on living, pumping hearts without any trouble.
On the other hand, none of their techs were exactly open-torso surgeons. Still, as the days progressed and the new circuit breakers gradually began to appear at the critical junction points, McLeod's permanent expression of impending doom started to ease a little. He began to let the techs work without hovering over their shoulders, spending more time in the wardroom with his crew and any of the ONI team who happened to be off duty, sometimes regaling them with stories of his days in the Navy.

***Snip***

She turned back to her displays, ignoring Wallace's look of disbelief. In the distance, the battlecruiser's wedge fluctuated again—

—and with a distant thundercrack and a jolt that could be felt straight through the deck plates, Dorado's wedge collapsed.
"Hot diggedy damn," Captain McLeod's strained voice said into the sudden silence. "Is that what was supposed to happen?"
"Part of it," Sandler assured him, crossing to the engineering status board. "Georgio?"
"Don't know yet," Pampas said, his fingers playing almost tentatively with the keys. "The breakers are still popped, but they might just be too hot to reset."