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Ship Tare Mass?

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Re: Ship Tare Mass?
Post by WeberFan   » Thu Aug 04, 2016 11:35 am

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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.

What is it logisticians say? "Empty space is always the most expensive cargo to ship..."
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Re: Ship Tare Mass?
Post by HB of CJ   » Thu Aug 04, 2016 6:31 pm

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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.
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Re: Ship Tare Mass?
Post by kzt   » Thu Aug 04, 2016 6:34 pm

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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.
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Re: Ship Tare Mass?
Post by HB of CJ   » Thu Aug 04, 2016 7:52 pm

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Perhaps it may be one of the many small mistakes that are impossible to find and correct when the Honorverse covers so much ground with so many words in so many excellent space opera books.

To have a profitable merchant ship built so strong that it could survive hundreds of gees acceleration without compensators is not reasonable. Not by hundreds of times reasonable at all.

To build such a hull would result in no profitability in the matter. It would take too much expensive materials and tech to even approach such strength. Perhaps the compensators are built into the fabric of the ship?

Always operational. Non removable. So when even empty and unmanned, such devices give the ship the required structural integrity allowing very little material to be used in construction.

Consider compensators to be like energy force fields built into the guts of the ship that are responsible for the hull to be strong enough. Also the compensators would protect the crew and cargo when loaded?

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Re: Ship Tare Mass?
Post by Jonathan_S   » Thu Aug 04, 2016 10:09 pm

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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. :roll:
Just mildly overbuilt </sarcasm>
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Re: Ship Tare Mass?
Post by Vince   » Thu Aug 04, 2016 10:18 pm

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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. :roll:
Just mildly overbuilt </sarcasm>

Keep in mind that while a merchant ship is a very expensive proposition (starting at one billion Manticoran dollars IIRC), crews are relatively cheap. So it would make sense to overbuild merchant ships so that you can recover it for reuse if the inertial compensator fails (after you scrape up the anchovy paste remains of the crew off the deck plates).
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Re: Ship Tare Mass?
Post by Jonathan_S   » Thu Aug 04, 2016 10:43 pm

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

Keep in mind that while a merchant ship is a very expensive proposition (starting at one billion Manticoran dollars IIRC), crews are relatively cheap. So it would make sense to overbuild merchant ships so that you can recover it for reuse if the inertial compensator fails (after you scrape up the anchovy paste remains of the crew off the deck plates).

Actually given the exceedingly low rate of compensator failure (especially in freighter that are often hard wired to be impossible to push past 80% power; and are far less likely to suffer battle damage) that probably doesn't make economic sense.

You're paying to overbuild 100% of freighters in the hopes of recovering the miniscule fraction that will suffer compensator failure in their lifetime; probably less than 20, in all of known space, per century.




Throwing some numbers around I think a reasonable case can be make for a lower bound of a bit over a 1/4 million freighters serving the known universe. If so, given the loss rate I speculated, a freighter would have roughly a 1 in 13,000 chance of suffering a compensator failure over a 100 year operation life. (which actually seems too high a rate).
Given that, economic breakeven means that it would have to add less that 0.00769% to the construction cost for it to make any sense to design it to survive compensator failure. (And that ignores the costs to chase it down, kill it's accel, board it, then repair and refurbish it).
If it costs more than that it's cheaper to write off those 20 ships and build replacements.

A billion dollars is a lot of money, but the extra it's worth to pay to protect that billion is a mere $77,000 more (using the guestimates above)
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Re: Ship Tare Mass?
Post by Somtaaw   » Thu Aug 04, 2016 10:46 pm

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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.


Seems Honorverse cargo ships are built more around "great big empty space", if you have a more specialized cargo, you'll have them loaded into specialized cargo pallets that then get loaded into a generic bay.

The only time they went more of a possible specialized ship, that was intended for use in Silesia turned out to be a big failure. Although that design was then purchase for use in Maya, as part of their Sepoy Option. Because what looks like a badly built merchant to OFS HQ, is really a pocket Q-ship when they get the sidewall modules, and other goodies that Erewhon hadn't built at the time of defending Torch.
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Re: Ship Tare Mass?
Post by Lord Skimper   » Fri Aug 05, 2016 2:29 am

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Compensators work on displacement, the ships are determined by size in displacement of alcohol. Why alcohol, no-one knows.

PS The line art pictures in HOS House of Steel are not accurate for the most part aside the centre colour pictures. Nike is very close. Most other would be longer than portrayed. King William is almost right on.

Wedge compensators make ships weightless they have no more mass nor are they affected by acceleration stresses. Full or empty in a wedge it makes no difference.
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Re: Ship Tare Mass?
Post by Dalin   » Fri Aug 05, 2016 5:07 am

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I would go with how much energy the ship needs to go with 1g acceleration. And then convert that energy to a weight.
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