Dichotomy of maintenance

Discuss the Traveller RPG and its many settings
phavoc
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Dichotomy of maintenance

Postby phavoc » Sat Mar 31, 2018 5:57 pm

On the one hand star ships are supposed to be tough, and last for 80 to 100 years. But on the other hand life support systems have to be maintained even when not in use.

Does the difference strike anyone else as odd? Ships that can exist for a hundred years but subsystems can't for more than a week.
Sigtrygg
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Re: Dichotomy of maintenance

Postby Sigtrygg » Sat Mar 31, 2018 6:31 pm

Other that life support consumables what ship sub-systems only last a few weeks?

Life support consumables include food, air filtration mesh, antibacterial and antiviaral filters, water purification, carbon dioxide scrubbers etc.
AnotherDilbert
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Re: Dichotomy of maintenance

Postby AnotherDilbert » Sat Mar 31, 2018 6:47 pm

Not really.

Tanks are tough, but still needs lots of maintenance, especially after a few decades.
AnotherDilbert
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Re: Dichotomy of maintenance

Postby AnotherDilbert » Sat Mar 31, 2018 6:49 pm

Sigtrygg wrote:
Sat Mar 31, 2018 6:31 pm
Other that life support consumables what ship sub-systems only last a few weeks?
Jump drives are finicky and needs some maintenance after each jump (JTAS24, Jumpspace).
arcador
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Re: Dichotomy of maintenance

Postby arcador » Sat Mar 31, 2018 7:22 pm

It's a conspiracy by the big-maintenance-service companies.

But thanks to a few webcam some-tube videos, pilots all over the known universe start to realize and can save tons of money from maintenance that goes into the banks of the big-M coprs. Pilots just have to get a simple solution their ancestors have used over a millennia ago, and luckily there is a net-address in the description of the video, which everyone can visit and make the solution themselves, just for a meagre sum of credits.
Condottiere
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Re: Dichotomy of maintenance

Postby Condottiere » Sat Mar 31, 2018 7:35 pm

1. Nuclear submarine life support systems; how much do ours cost?

2. Ramen.

3. Tank of water.
Sigtrygg
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Re: Dichotomy of maintenance

Postby Sigtrygg » Sat Mar 31, 2018 7:48 pm

AnotherDilbert wrote:
Sat Mar 31, 2018 6:49 pm
Sigtrygg wrote:
Sat Mar 31, 2018 6:31 pm
Other that life support consumables what ship sub-systems only last a few weeks?
Jump drives are finicky and needs some maintenance after each jump (JTAS24, Jumpspace).
Good call, but there is no associated credit cost.
Life support requires consumables and without them your life support breaks down, jump drive requires maintainance between jump but has no component cost, so what else is there?
Condottiere
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Re: Dichotomy of maintenance

Postby Condottiere » Sat Mar 31, 2018 7:56 pm

In terms of maintenance cost over actual time of operation, percentage wise the the jump drive is really large.
ShawnDriscoll
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Re: Dichotomy of maintenance

Postby ShawnDriscoll » Sat Mar 31, 2018 7:57 pm

Look at the USS United States. or any vehicle that is left to rot outside. How long do you think an air-cushioned high-speed monorail will last if mothballed and left in a desert?
rust2
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Re: Dichotomy of maintenance

Postby rust2 » Sat Mar 31, 2018 8:05 pm

phavoc wrote:
Sat Mar 31, 2018 5:57 pm
On the one hand star ships are supposed to be tough, and last for 80 to 100 years. But on the other hand life support systems have to be maintained even when not in use.
Well, plant a couple of flowers in your leisure area and most of the problem is gone (High Guard, page 44):

Biosphere
This is an area depicted to flora and fauna, either for
the production of food or as a leisure area. Every ton
dedicated to a biosphere will eliminate the life support
costs for two passengers.
Biosphere consume 1 power and cost Mcr0.2 per ton.
"Mind like parachute, functions only when open"
Condottiere
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Re: Dichotomy of maintenance

Postby Condottiere » Sat Mar 31, 2018 8:11 pm

I've gone over those calculations; it's about nine years to pay it off. Or eleven.
Reynard
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Re: Dichotomy of maintenance

Postby Reynard » Sat Mar 31, 2018 11:11 pm

Even a thick metal hull will deteriorate from the harshness of space. Everything else is far less resistant to wear and time. Complexity breeds fragility. Even paintings and statues sitting around deteriorate. The price of objects, expensive or not, is maintenance.

"I had a guaranteed military sale with ED 209 - renovation program, spare parts for twenty-five years... Who cares if it worked or not? "
Dick Jones
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Re: Dichotomy of maintenance

Postby Epicenter » Sun Apr 01, 2018 12:46 am

phavoc wrote:
Sat Mar 31, 2018 5:57 pm
Does the difference strike anyone else as odd? Ships that can exist for a hundred years but subsystems can't for more than a week.
Yeah, it's pretty weird. I think in a sense we're back to the "Ship of Theseus" issue. There is this entity called "a ship" that is conceptually separate from its subsystems that a lot of people (both writers and players) run into. A starship is the sum of its subsystems and it's understandable (and desirable) to simplify and abstract a lot of systems for bookkeeping, but I do think all parts of a ship should require maintenance, even if it is just "general maintenance."
Linwood
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Re: Dichotomy of maintenance

Postby Linwood » Sun Apr 01, 2018 2:15 am

Since IRL I work as an engineer in the transportation industry maintenance rules have always made sense to me. All filters eventually clog over time. All coolants and lubricants eventually break down. Batteries degrade every time they heat up - and they heat up every time current flows in or out. Electronic components like capacitors and MOSFETS degrade in use as well.

I don’t picture a spaceship as being a one-horse shay. The base structure might last for millennia; the heavy power systems might keep working for centuries. But some things will wear out sooner - or go out of calibration, or run out of a crucial consumable. So without preventive maintenance I would expect growing penalties on its use as the small issues pile up.

Not to mention - if you expect to earn credits hauling passengers you’re going to have to do some fairly frequent cleaning. Nobody wants to pay to fly star to star in a ship that smells like a garbage scow.
AnotherDilbert
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Re: Dichotomy of maintenance

Postby AnotherDilbert » Sun Apr 01, 2018 10:22 am

rust2 wrote: Well, plant a couple of flowers in your leisure area and most of the problem is gone (High Guard, page 44):

Biosphere
...
Condottiere wrote:
Sat Mar 31, 2018 8:11 pm
I've gone over those calculations; it's about nine years to pay it off. Or eleven.
Not quite.

Take a bog standard 400 Dt trader (J-2, 10 High, 10, Mid, 10 Low, 85 Dt cargo). At full capacity the economic potential looks something like this:
Image
With Revenues of kCr 359 and costs of kCr 221.3 we can make an income of kCr 137.7 per jump.

Now add 10 Dt Biosphere:
Image
The mortgage goes up slightly and the life support costs goes down so the costs decrease to kCr 216.4 but at the same time cargo space has decreased so max revenue decreases to kCr 343 for a potential income of kCr 126.4, hence we lose money on the Biosphere and it will never pay back the investment.
Reynard
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Re: Dichotomy of maintenance

Postby Reynard » Sun Apr 01, 2018 11:35 am

Plus there should realistically be an attendant for the biosphere. Any gardener or farmer will tell you a greenhouse environment doesn't remain viable and productive on its own. Maybe you can have three drones, Huey, Louie and Dewey, programed to care for the biosphere but that's also costly.
Condottiere
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Re: Dichotomy of maintenance

Postby Condottiere » Sun Apr 01, 2018 11:13 pm

Image

I'm pretty sure you reach equilibrium in nine years if the biosphere breathes in the cost of life support, and eleven if you include paying off the power plant and fuel consumed.

As regards the spaceship in general, every decade you acquire a quirk, which if it bothers you too much, I'm fairly sure some time in the 'yard will remove it.
AnotherDilbert
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Re: Dichotomy of maintenance

Postby AnotherDilbert » Sun Apr 01, 2018 11:29 pm

Condottiere wrote: I'm pretty sure you reach equilibrium in nine years if the biosphere breathes in the cost of life support, and eleven if you include paying off the power plant and fuel consumed.
You have not counted the opportunity cost of lost cargo space?
Condottiere wrote:
Tue Sep 27, 2016 2:25 pm
Outside of loss of volume, it would take about ten or eleven years to break even, if life support costs are a thousand schmuckers per person per month.
Since the opportunity cost varies with jump capability, the repayment period must vary with jump capability, if it could repay the investment.

Unfortunately with the opportunity cost, it can't pay back the investment.
Condottiere
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Re: Dichotomy of maintenance

Postby Condottiere » Sun Apr 01, 2018 11:51 pm

I'm a little sceptical that every cubic metre of a cargo ship will be get booked under normal activity.

Opportunity cost comes more in play with interstellar travel onboard starships, where you really could be packed to the gills, and I'm thinking a troop carrier.
AnotherDilbert
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Re: Dichotomy of maintenance

Postby AnotherDilbert » Mon Apr 02, 2018 10:49 am

Condottiere wrote: I'm a little sceptical that every cubic metre of a cargo ship will be get booked under normal activity.
I agree that freighters are not always full to capacity, but when you are is when you make your profit.

Traveller freight is a very marginal business.

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