IRL, banks can make more on that type of business line (using 10-20% down) than they do if the person does NOT default on the loan... Sneaky indeed.
Starship maintenance costs... what are they?
- Thread starter andycowley
- Start date
IRL, banks can make more on that type of business line (using 10-20% down) than they do if the person does NOT default on the loan... Sneaky indeed.
esampson
SOC-13
I suspect that your figure of 35 jumps per year might be a bit on the high side. In addition to the day out and day back in you probably need at least 1 day on the ground for stuff like cleaning of rooms, restocking, whatever it is that costs 2000 Cr per passenger for life support, etc. That's actually 10 days instead of 9. Then with 2 weeks taken out for annual maintenance you've got 351 days, so 35 jumps would give you practically no margin.
Your point that ships could probably make more than 25 jumps a year is completely correct, however. Even tramp ships could probably find cargo, freight, or passengers in less than a week if they were willing to lose some of their profit by looking for businesses that are set up for ships looking for quick turn around (customer who wants quick transport of their freight to a nearby planet goes to a company that specializes in the matter. When the ship touches down there's already a representative at the field looking for ships heading to the planet).
Again, the rules are highly abstracted and could be much more fleshed out to deal with these kinds of situations.
Travel time to and from safe jump distance from a size A world at 1G is 420 minutes. For any other size world it is less, of course. So out of the 48 hours a nine day average would give you, you have at least 34 on the ground (less the orbit to surface run which is an hour or two -- call it 30 hours to be on the safe side).
It's true that worlds inside the solar jump shadow will prolong the travel time and reduce the number of jumps. But then, such worlds would also reduce the number of jumps correspondingly for tramp ships.
Hans
esampson
SOC-13
True enough, but in the case of the tramp ship with the '1 week on ground' rule I think the reason that time is so long is an abstraction to handle those times when the ship has to arrive outside the star's jump shadow, so I wouldn't really worry about adding extra time to their trip.
I've also got to wonder if 1 day is really a long enough turn around. Anyone know how long a cruise ship and a cargo ship stay in port? Those might be pretty good indicators.
Of course there's also a difference in the normal turn around that might be made every stop and the occasional 'hurry up' turn around.
There will almost certainly be some randomization due to traffic control. In the real world ships coming into port are reporting their position days before they arrive and port traffic control has plenty of time to juggle things around. In the Traveller universe there's no way for a ship to report a late departure, unscheduled ships can't report that they are arriving until they precipitate, and even when a ship departs on schedule its final arrival time and locations are not entirely predictable, so I could definitely see a ship precipitate out and be put in a "holding pattern" for several hours. However, that's probably going to be a matter of a few hours and not 10-20 hours, I would expect, unless conditions were exceptional.
Also, if you are really working to try and accurate model the length of trips like that you quite probably have to take into account aspects of relative speed, which have to be matched, especially if precipitation has to occur at the edge of a star's jump shadow (since relative velocities could quite possibly be carrying you away from your destination unless you were to land on the completely opposite side of the shadow, which would be impractical).
Then again, maneuver drives do have a 1% efficiency in jump space, so you might be able to make an awful lot of velocity correction during that week. (Looks like nearly 60 km/s per G if someone wants to double check my math).
I've also got to wonder if 1 day is really a long enough turn around. Anyone know how long a cruise ship and a cargo ship stay in port? Those might be pretty good indicators.
Of course there's also a difference in the normal turn around that might be made every stop and the occasional 'hurry up' turn around.
There will almost certainly be some randomization due to traffic control. In the real world ships coming into port are reporting their position days before they arrive and port traffic control has plenty of time to juggle things around. In the Traveller universe there's no way for a ship to report a late departure, unscheduled ships can't report that they are arriving until they precipitate, and even when a ship departs on schedule its final arrival time and locations are not entirely predictable, so I could definitely see a ship precipitate out and be put in a "holding pattern" for several hours. However, that's probably going to be a matter of a few hours and not 10-20 hours, I would expect, unless conditions were exceptional.
Also, if you are really working to try and accurate model the length of trips like that you quite probably have to take into account aspects of relative speed, which have to be matched, especially if precipitation has to occur at the edge of a star's jump shadow (since relative velocities could quite possibly be carrying you away from your destination unless you were to land on the completely opposite side of the shadow, which would be impractical).
Then again, maneuver drives do have a 1% efficiency in jump space, so you might be able to make an awful lot of velocity correction during that week. (Looks like nearly 60 km/s per G if someone wants to double check my math).
Midgardsormr
SOC-10
That was actually more directed at myself than anyone else, because I'd written about three paragraphs on space station economics before I came to my senses!
Er... Yeah. Bad math. I think I did the division based on the 1MCr of the entire system, and then forgot what I'd done.
Incidentally, my estimate of 10 (working) jumps per year is based on the assumption of a group of adventurers who are also taking patron jobs and otherwise getting involved in shenanigans, which is how my games typically run. My players spend relatively little time in the trade system, so I try to set up the economics so that if they don't spend any table time dealing with it, they're breaking even. They actually do around 12 jumps per year, but I put up with a lot of slop for the sake of easy math. And I still flub it regularly, as illustrated above!
As for the justification of the low costs I asserted, I am thinking about systems and businesses where, for instance, a recharge of the atmosphere system involves replacing a pre-loaded canister. Leave the old one with the starport, where someone has a business that collects the canisters, recharges them, replaces filters and scrubbers, then leaves the newly prepared canister for the next ship. Like propane tanks. If you're dealing with the limited needs and vast budgets of a navy, then $1,000 per week is reasonable (for large values of "reasonable"). If a port starts supporting a large fleet of passenger submarines, then inevitably someone's going to come up with an idea that makes the thing far cheaper and faster. Other systems will likely have similar services.
One thing I definitely did overlook was entertainment licensing. The Recording Industry Association of the Third Imperium is going to get their cut, too, I'm sure.
Anyway, there are enough variables and enough ways to slice them that pretty well any number can be reasonably justified, as long as it falls within the limits of the ticket price.
So coming at it from the other direction, if the (conservative) business plan calls for a liner to make 25 jumps per year at 80% capacity of mid passage tickets, what is the absolute most you can pay for operations to make the venture successful?
And on a related note, are there any rules concerning crew wages in T5? I haven't run across them yet, but I didn't read the book systematically.
The last cruise ship I was on arrived in port pre-dawn and set sail for a next cruise about 4pm ... Less than 12 hours arrival to departure.
I think cargo ships vary based on how long it takes to load/unload cargo.
esampson
SOC-13
I found a site called www.marinetraffic.com, and it is kind of interesting. Not really organized to give me all the data I want but it looks like a lot of the cargo ships are in port for less than a day. Unfortunately I can't tell how much of their cargo is being loaded or unloaded, but still pretty telling that they are able to really get those things in and out of there.
pendragonman
Absent Friends Margrave
The reason they are in port less than a day is their cargoes are already booked and just need to be loaded/unloaded. They are not speculating, they are just hauling cargo. Same goes for regular cruise ships, they are pre booked.
What is more difficult is figuring out how long a tramp steamer with an irregular route is in port, even if it is just in port to haul cargo and not speculate or round up a load of passengers.
I'm almost certain that somewhere I've seen a statement about port routine of PC ships that says that upon arrival all available freight loads are rolled up, and based upon that a new destination is selected with departure sheduled for five days later. During those five days passengers show up.
However, I've just gone through The Traveller Book and can't find any such statement, so perhaps I'm misremembering.
Hans
esampson
SOC-13
Right. I'm not debating the fact that a tramp ship buying and selling cargo would probably take longer (although on planets with advanced mercantile centers I would imagine you could actually do it pretty quick if you were of a mind to). Just sort of trying to figure out what the lower end on turnaround would be.
In the case of a tramp steamer hauling freight I would imagine it spends just as much time in port as a ship on a regular route. It's only coming into port because there is a shipment that either needs pickup or delivery and that will have been scheduled before they even arrive.
Speculative cargo and rounding up your own passengers would be a different case, of course and would be probably be determined through a combination of the population of the planet, trade codes, expected ship traffic, and how much time the crew spends looking (if they take the first thing that comes their way they probably won't make as much money, but turnaround would be faster).
Technically according to the (old) rules there still needs to be the 2000 Cr per passenger maintenance done on the life support, but I would speculate that A) that could probably be done within a day and B) there has to be some way to defer it because Scout/Couriers doing exploration duty can't have their life support cleaned up after every jump (nor could any ship using drop tanks to do successive jumps).
For reasons of abstraction I would probably generally rule quick turnaround to be a day although it might be nice to have even finer gradation in case a ship has to do a turnaround in 'Jaynestown' or something like that where even spending 8 hours on the surface might be too much.
Low end on consistent turnaround times (IE, how tight you can schedule) is hampered by the 168±16.8 hours... add another (2*(6.7+2.1+.7))=19 hours for Size A travel times at 1G (taken from MT IE, p. 93) (Size 5 is 17.4 hours, size 1 is 6 hours). Minimum on a scheduled route with no "turn around time" is thus size 1 to size 1 = 168+16.8+6=190.8 hours., or 7.95 days; Size A to Size A is 8.49 days...
Allowing for a ready, containerized cargo, and optimal unload and loading systems, figure 4Td/minute per crane that can hit it, and lets' assume 1 crane per 100Td of cargo bay, we can offload in 25 minutes, and reload in another 25. The issue then being, how fast can we feed cargo to the cranes... but we'll ignore that for now. (as an aside, Port of Anchorage can unload faster than it can move cargo out, due to a 2 lane road access with a timer controlled stoplight... and 3 cranes...)
Crew can be ready to debark, but embarking crew need at least 30 minutes, and then the transfer walkthrough and checklists. For safety's sake, call it at least 2 hours.
Then there's fuel. it's likely that fuel can be loaded while the cargo's being unloaded, but now we're talking dedicated hull specific docking features to do this all at once.
As an alternate mode, a through-deck system, like a type R, could be tractor loaded with rolling stock, and load while unloading...
But let's be kind, and generous, and call it a 4 hour turn around. 8.75 days... round it up to nine days. 3.11 jumps per 28 day Imperial month, 12.5 months per operating year. 38.8 jumps per year.
If, however, you have any reason to roll for misjumps, things go sideways. In MT, with the must-roll and autofail & auto mishap on nat 2, you will have a 1d6+4 day jump about once a year... and an "8 hours out" jump about as often.
Allowing for a ready, containerized cargo, and optimal unload and loading systems, figure 4Td/minute per crane that can hit it, and lets' assume 1 crane per 100Td of cargo bay, we can offload in 25 minutes, and reload in another 25. The issue then being, how fast can we feed cargo to the cranes... but we'll ignore that for now. (as an aside, Port of Anchorage can unload faster than it can move cargo out, due to a 2 lane road access with a timer controlled stoplight... and 3 cranes...)
Crew can be ready to debark, but embarking crew need at least 30 minutes, and then the transfer walkthrough and checklists. For safety's sake, call it at least 2 hours.
Then there's fuel. it's likely that fuel can be loaded while the cargo's being unloaded, but now we're talking dedicated hull specific docking features to do this all at once.
As an alternate mode, a through-deck system, like a type R, could be tractor loaded with rolling stock, and load while unloading...
But let's be kind, and generous, and call it a 4 hour turn around. 8.75 days... round it up to nine days. 3.11 jumps per 28 day Imperial month, 12.5 months per operating year. 38.8 jumps per year.
If, however, you have any reason to roll for misjumps, things go sideways. In MT, with the must-roll and autofail & auto mishap on nat 2, you will have a 1d6+4 day jump about once a year... and an "8 hours out" jump about as often.
What trav formula is the I.E. using? Looks completely different from the accel/decel one.
I just cracked mine open. Size A travel time from 100D at 1G is 6.7 hours...
esampson
SOC-13
Not sure where MT get's its time from but I'm guessing there's a different limiting factor or something on jumping (been a long time since I looked at those rules).
Let me know if I'm getting something wrong here:
Size A planet has a diameter of 16,000 km.
100D out from 16,000 km is 1,600,000 km.
Half that distance is your 'turnaround' where you have to start decelerating, so 800,000 km or 800,000,000 m.
800,000,000m / 1/2 of 10m (for convenience) = 160,000,000
160,000,000.5 = 12,649
12,650 * 2 (since we will spend as long after turn around as we did before it) = 25,300
25,300 / 3600 = 7 hours, 1 minute, 40 seconds.
So by my math that is way under 19 hours. What's more, that's assuming you are coming in from a dead stop, which to me is crazy because you retain your initial velocity. Let's assume you jumped in from a fairly normal size 5 world. You would have had to fly 800,000 km away from the planet which at 1 G would have taken roughly 3.5 hours. When you jumped you would have had a velocity of about 63 km/s. You would continue to accelerate towards your destination for another 48 minutes before turn around and then decelerate for 4 hours and 18 minutes.
Trip time from precipitation to planet would be 5 hours and 36 minutes.
All of this assumes that the relative velocities of the planets are identical. If there is any difference at all then the time will be decreased because the ship can jump in on a vector either ahead of or behind the target planet, depending on what is best.
Of course there's also some safety margins since you can't be sure exactly where or when you'll drop out and possibly you wouldn't be able to take the most optimal course because of masses in the way during the jump but you are looking at somewhere between a bit over 5 1/2 hours for a suicidally confident astrogator and 7 hours for an overly cautious one, not 19.
That is unless I've missed something, which is entirely possible.
Let me know if I'm getting something wrong here:
Size A planet has a diameter of 16,000 km.
100D out from 16,000 km is 1,600,000 km.
Half that distance is your 'turnaround' where you have to start decelerating, so 800,000 km or 800,000,000 m.
800,000,000m / 1/2 of 10m (for convenience) = 160,000,000
160,000,000.5 = 12,649
12,650 * 2 (since we will spend as long after turn around as we did before it) = 25,300
25,300 / 3600 = 7 hours, 1 minute, 40 seconds.
So by my math that is way under 19 hours. What's more, that's assuming you are coming in from a dead stop, which to me is crazy because you retain your initial velocity. Let's assume you jumped in from a fairly normal size 5 world. You would have had to fly 800,000 km away from the planet which at 1 G would have taken roughly 3.5 hours. When you jumped you would have had a velocity of about 63 km/s. You would continue to accelerate towards your destination for another 48 minutes before turn around and then decelerate for 4 hours and 18 minutes.
Trip time from precipitation to planet would be 5 hours and 36 minutes.
All of this assumes that the relative velocities of the planets are identical. If there is any difference at all then the time will be decreased because the ship can jump in on a vector either ahead of or behind the target planet, depending on what is best.
Of course there's also some safety margins since you can't be sure exactly where or when you'll drop out and possibly you wouldn't be able to take the most optimal course because of masses in the way during the jump but you are looking at somewhere between a bit over 5 1/2 hours for a suicidally confident astrogator and 7 hours for an overly cautious one, not 19.
That is unless I've missed something, which is entirely possible.
Not so. The freight is sitting in a warehouse, ready to be loaded whether you arrive 17 hours early or late or anything in between. Passages can be sold on the understanding that the passenger must be ready to show up at the starport any time within the window with notice being given the moment the ship arrives in the system. So a turnaround of 72 hours from arrival will result in an average time of 10 days per jump.
Hans
esampson
SOC-13
Actually, looking at the jump rules for T5 the variance is Flux*2, so it would only be a window of plus or minus 10 hours, not 16.5. Also, it looks like the astrogator doesn't need to be as crazy as I thought. If the exit point is delayed the ship still cannot drop out less than 100D from a gravitational body, so there's no danger of crashing into the planet unless you have an absolutely suicidal amount of velocity when you arrive (velocity so high that you might as well have been trying to fly straight into the planet anyway).
6.7 hours is the time to get from 100D to 10D, then you have to add in the time to get from 10D to orbit (2.1) and then from orbit to surface (0.7). Then he just multiplied it by two for there-and-back.
If you are at 100D and travel for 6.7 hours ~ 1G you have covered 100D's of distance & are at the planet. NOT still 10D's out.
o:
esampson
SOC-13
As I think more about it, arriving early is a non-issue for the purposes of a scheduled run. The worst thing that happens is that the berth is not ready for the ship and it has to remain in orbit. What you really want to look at for the purposes of scheduling a run is probably your 'launch to launch' time.
I think you can fairly safely assume 10 hours spent under thrust for a 1 g ship. That's the amount of time it would take to accelerate to 100D from a size A world and then to declerate back down to 0 for a size A world. If either world is smaller than a size A the turnaround will occur at a different time (either before or after jump) and time under thrust would be decreased. The primary time this would not be true would be for a planet within a star's occlusion distance. However in pretty much all cases planets within a star's occlusion distance are also well within the habitable zone. Since main worlds tend to be in the habitable zone we should only rarely need to drop out any further than 100D from them.
Over 90% of the time you will arrive with 174 hours after jumping (1 week, 6 hours). Add the 10 hours of thrust time and you are looking at 1 week, 16 hours. Assume about 1 hour to land and another to launch (based upon way too many hours spent playing Orbiter) and it is 1 week, 18 hours.
Now comes turn over with getting passengers and freight unloaded, rooms cleaned, systems serviced, refueling, new passengers and freight loaded. Based on what I've seen with large container ships and cruise ships it honestly looks like that could be done in 12 hours. Quite possibly faster but let's just leave it at 12 hours.
That means that the ship can reasonably be counted on as being ready for launch 1 week, 30 hours, or 8.25 days, after its last launch. That can even be shaved down a little if you want to increase the odds that the ships will be 'running late' and will have to make up time with jumps shorter than the budgeted time.
That should give a ship working a regular line between 39 (assuming a jump every 9 days) and 43 (assuming a jump every 8 days) jumps a year with 14 days for scheduled maintenance.
I think you can fairly safely assume 10 hours spent under thrust for a 1 g ship. That's the amount of time it would take to accelerate to 100D from a size A world and then to declerate back down to 0 for a size A world. If either world is smaller than a size A the turnaround will occur at a different time (either before or after jump) and time under thrust would be decreased. The primary time this would not be true would be for a planet within a star's occlusion distance. However in pretty much all cases planets within a star's occlusion distance are also well within the habitable zone. Since main worlds tend to be in the habitable zone we should only rarely need to drop out any further than 100D from them.
Over 90% of the time you will arrive with 174 hours after jumping (1 week, 6 hours). Add the 10 hours of thrust time and you are looking at 1 week, 16 hours. Assume about 1 hour to land and another to launch (based upon way too many hours spent playing Orbiter) and it is 1 week, 18 hours.
Now comes turn over with getting passengers and freight unloaded, rooms cleaned, systems serviced, refueling, new passengers and freight loaded. Based on what I've seen with large container ships and cruise ships it honestly looks like that could be done in 12 hours. Quite possibly faster but let's just leave it at 12 hours.
That means that the ship can reasonably be counted on as being ready for launch 1 week, 30 hours, or 8.25 days, after its last launch. That can even be shaved down a little if you want to increase the odds that the ships will be 'running late' and will have to make up time with jumps shorter than the budgeted time.
That should give a ship working a regular line between 39 (assuming a jump every 9 days) and 43 (assuming a jump every 8 days) jumps a year with 14 days for scheduled maintenance.
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