Maneuver Trumps Jump drive in system

[tytalan]

Every so often we hear someone talking about a in system jump to deliver cargo but this would almost never happen. Why you ask? Because simply put a system jump is slower and less economical than using a Maneuver drive in system. How simple look at the numbers every jump requires a average of 10% the tonnage of the ship just for the jump drive, that on top of the PP (which has to be larger to support the Jump D). and Maneuver while a system ship only requires a maneuver drive and power plant. Once you reach TL 10 in system travel is as fast or faster (M3 will get most places in a single star system faster). Even multiple stars star system’s the deep space maneuver system makes jump still impractical. In short Maneuver drive is fast and more economical than doing a in system jump

 

[Arkathan]

In most cases, yes. However, there are situations in which a jump makes more sense.
A free trader is in a mining system with an asteroid belt in the Jupiter orbital slot. The trader has an opportunity to get supplies to a facility on the other side of the ring. Jumping would be faster than using the M-Drive.
Similarly, Neptune station needs to get materials from Uranus. They are in opposition relative to Sol.
Using the 1000D rules, which I ignore, scientists need to be rescued from from Makemake.
Pirates roam the areas of open space not patrolled close to the colonized planets.

So, yes. An in system spaceship with high (for a trader) acceleration is going to carry more stuff faster and cheaper than a tramp starship...
but never underestimate a free trader captain desperate to make his next mortgage payment, or other conditions that set up an adventure for players.

Going back to the last sentence. If you need a DSMS to navigate between a binary/trinary system, a jump is almost always going to be faster, assuming habitable zone to habitable zone travel. Close companions COULD meet your criteria.

 

[Condottiere]

1. Commercially, it probably needs a very specific business case.

2. In terms of cost, the difference would be fuel and engineering.

3. Default, refined fuel costs for a jump at fifty starbux per tonne of volume; minimize that, and your operating costs drop.

4. It could also be a question of economies of scale.

5. A jump factor/one drive for a ten kilotonne freighter would be two hundred fifty five tonnes at three hundred eighty two and a half megastarbux.

6. A manoeuvre drive factor/nine would be nine hundred tonnes at one and two fifths gigastarbux.

7. You'd also need a power plant that can sustain energy generation at twenty kilo power points.

8. Whereas you only need a single surge of one kilo power points for one round.

9. Plus two kilo power points per round for basic systems.

 

[J. L. Brown]

In-system traders ought to have access to a Jump-0.
0.0625% of ships volume, plus 5 dTons (minimum of 10 dTons); requires 2.5% of ships volume in fuel; TL 8 or 9; maximum jump distance ~51500 AU. Requires Ship Tonnage x0.1 x Jump rating of 0.25 = 2.5 power per 100 dTons; advanced batteries could minimize need to resize the PP.

This probably is a compelling choice for System Defense Boats, too.

For a M-9 ship, anything over 55 AU is probably better done with a jump.
For other ships with different thrust ratings:
M-8 it is 48.9 AUs
M-7 it is 42.8 AUs
M-6 it is 36.6 AUs
M-5 it is 30.5 AUs
M-4 it is 24.5 AUs
M-3 it is 18.3 AUs
M-2 it is 12.2 AUs
M-1 it is 6.1 AUs

Since 'distance' is such a big factor, it is the referee's call. If the vast majority of commerce is within 27 AU of most (or all) system primaries, then M-9 merchants might rule.

 

[Condottiere]

I had a go at designing a factor/zero jump drive, principally using Interstellar Wars as a template.

Unless there's a change in design or customization rules, it's kinda pointless, since you end up with a factor/one.

At least with a factor/zero manoeuvre drive, you do get some token benefits.

 

[tytalan]

In most cases, yes. However, there are situations in which a jump makes more sense.
A free trader is in a mining system with an asteroid belt in the Jupiter orbital slot. The trader has an opportunity to get supplies to a facility on the other side of the ring. Jumping would be faster than using the M-Drive.
Similarly, Neptune station needs to get materials from Uranus. They are in opposition relative to Sol.
Using the 1000D rules, which I ignore, scientists need to be rescued from from Makemake.
Pirates roam the areas of open space not patrolled close to the colonized planets.

So, yes. An in system spaceship with high (for a trader) acceleration is going to carry more stuff faster and cheaper than a tramp starship...
but never underestimate a free trader captain desperate to make his next mortgage payment, or other conditions that set up an adventure for players.

Going back to the last sentence. If you need a DSMS to navigate between a binary/trinary system, a jump is almost always going to be faster, assuming habitable zone to habitable zone travel. Close companions COULD meet your criteria.

Actually if you do the math a m4 or higher ship with a DSMS is not only likely to be faster but far far more economical. When it takes 2 free traders to carry the same cargo as a in system ship the same size as one of the free traders that’s a massive cost savings. Also remember just because you leave the 1000d doesn’t mean your ship suddenly stops moving it just kills acceleration and a M4 with a TL 13 DSMS is still getting 1 G thrust.

 

[Arkathan]

Now you are moving the bar. In your original post, you were happy with an M3. See the chart that JL Brown posted.
As to your DSMS: Rigil Kentaurus or Toliman to Proxima Centauri.
Even between Alpha and Beta Centauri, at aphelion, you need an M6 to break even. Your M3 breaks even only at perihelion.
When time matters, you don't worry about which can carry more, more efficiently. You worry about evacuating your people or getting emergency supplies as quickly as possible.

There are situations in which your scenario works, and there are situations in which it does not work as well as other choices.

 

[tytalan]

1. Commercially, it probably needs a very specific business case.

No it doesn’t. There are three major factors
1) time a jump takes 7-8 days no matter the distance M drive it’s a matter of thrust that determines travel time.
2) a 200dt M 4 drive ship has easily 150 dt of cargo that’s two 200 dt of free trader
3) that same M4 ship takes 8 dt fuel for 12 weeks of travel while those 2 free traders are going to take over 480 dts of fuel durning those 12 weeks. Even with decreased jump fuel your taking over 408dt (15% decrease in fuel requirements) of fuel also to achieve this decrease in fuel for the jump drive you had to increase the base cost and maintenance cost of you jump drive by 50%.

Using the CRB as a rule of thumb travel time to a Far Gas Giant with M2 is about 5 days a M3 or M4 is much less in fact if my numbers are right the M4 can make a trip there and back in the time the two free traders jump one way so twice the cargo runs at considerable less cost in both overhead and fuel. Now these numbers are not exact but they are good enough to show the economic benefits.

Now longer runs say two different stars in a binary is going to require both the DSMS and a higher M rating but since a DSMS of TL 13 give you 25% of you base thrust with a M6 get you 6g thrust until you leave the 1000d limit that you have 1.5 g thrust until you renter the 1000d limit. The 6g time frame can also be increased by traveling in a way to use other bodies 1000d limit. You do lose some cargo by going to M6 but that still offset but the much higher overhead Costs of even one freetrader. Yes in binary star system there are cases where it can be faster to do a system jump but unless the stars are so far apart to require 2weeks or more for the maneuver drive to travel it’s still by far more economical to go by maneuver drive.

Now maneuver drive does cost more per ton than Jump drive that that’s basically a wash since the jump drive has a +10 tons to size and the ship in question still needs a maneuver drive.

Now transporting people is a slightly different in the economic but the main difference here is the maneuver drive ship is much more likely to be either pure cargo or pure personal which also helps with the economics.

 

[Arkathan]

OK, you are arguing against it being a specific business case, and then you specify purpose built ships.
Now, let us compare two purpose built ships.
Both simple cargo haulers.
One is a stripped down M6 with a DSMS.
One is a J1/M1 hauler.
The cost : DSMS is more expensive, like nearly 1.5 the cost of the J1M1 ship
The difference in their cargo is 5 tons. Jump ship loses by 5 tons.
The Jump capable ship requires an astrogator. Jump ship loses by 6,000Cr per month.

So, you see, with a specific business case, you have relatively equal outcomes.
In some situations, you can accept the additional upfront costs that will be offset later.
In some situations, you can't afford to wait for 5 tons per run and 6000Cr per month to make up for 15MCr.
In some situations you can stay in normal space, in some situations you need to take the shortcut.

Your scenario is not WRONG, necessarily, but it requires a certain point of view, and a specific set of circumstances in order to make it economically feasible. Just like the jump capable ship requires a certain point of view and set of circumstances to make its use worthwhile.

 

[WHULorigan]

Even between Alpha and Beta Centauri, at aphelion, you need an M6 to break even. Your M3 breaks even only at perihelion.

Minor quibble: You mean Alpha Centauri A and Alpha Centauri B. The Alpha Centauri system and the Beta Centauri system are nowhere near each other in space; only near each other in the constellation Centaurus as seen from the surface of Terra.

 

[WHULorigan]

In general I like the idea of M-Drives being used more commonly other than just getting to the Jump-point, or for combat maneuvers. I suppose you could make the argument that in-system jumps run a higher risk of a jump line obstruction (by some small uncharted unexpected object, piece of debris, or another ship) that will precipitate you out of jump at an unexpected location at the end of a week, so it might not be considered worth it except out of necessity.

 

[tytalan]

OK, you are arguing against it being a specific business case, and then you specify purpose built ships.
Now, let us compare two purpose built ships.
Both simple cargo haulers.
One is a stripped down M6 with a DSMS.
One is a J1/M1 hauler.
The cost : DSMS is more expensive, like nearly 1.5 the cost of the J1M1 ship
The difference in their cargo is 5 tons. Jump ship loses by 5 tons.
The Jump capable ship requires an astrogator. Jump ship loses by 6,000Cr per month.

So, you see, with a specific business case, you have relatively equal outcomes.
In some situations, you can accept the additional upfront costs that will be offset later.
In some situations, you can't afford to wait for 5 tons per run and 6000Cr per month to make up for 15MCr.
In some situations you can stay in normal space, in some situations you need to take the shortcut.

Your scenario is not WRONG, necessarily, but it requires a certain point of view, and a specific set of circumstances in order to make it economically feasible. Just like the jump capable ship requires a certain point of view and set of circumstances to make its use worthwhile.

One the only specific design ship I listed would be the insystem ship since the design doesn’t exist.
Two the only reason to add a DSMS is in the specific case of multiple stars in 5he system.
Three most of the time as long as you have maneuver 3 or better the maneuver drive is the short cut.

You keep arguing that Jump is faster but that’s not the case, must of the time as long as you have at least a maneuver of 3 or better the maneuver is far faster in fact a maneuver of 2 is faster.

 

[Arkathan]

You keep arguing that an M-Drive is better in all circumstances.
It is not.
You have found a shiny hammer and every problem is now a nail. This is the same issue Truman had in WW2.
I am merely disabusing you of that logical fallacy.
You also seem to be ignoring when I tell you that in certain circumstances, you are not wrong.
In other situations, you are.

 

[Arkathan]

Minor quibble: You mean Alpha Centauri A and Alpha Centauri B. The Alpha Centauri system and the Beta Centauri system are nowhere near each other in space; only near each other in the constellation Centaurus as seen from the surface of Terra.

Yes, Thanks.

 

[NOLATrav]

In general I like the idea of M-Drives being used more commonly other than just getting to the Jump-point, or for combat maneuvers. I suppose you could make the argument that in-system jumps run a higher risk of a jump line obstruction (by some small uncharted unexpected object, piece of debris, or another ship) that will precipitate you out of jump at an unexpected location at the end of a week, so it might not be considered worth it except out of necessity.

Agreed but if you’re referring to T5’s Jump Lines and so forth, I do not dig that stuff. Another undercooked idea about how the universe works. If these ideas were fully implemented in the OTU interstellar commerce would be considerably reduced, which is anathema to what the Third Imperium is. We went from ‘Jump is exotic and Travellers are rare’ to ‘Jump is as common as international flights’ to ‘Jump is weird, you might end up back where you started a week from now.’ In-system jumps would be basically non-existent because as you say, any random object could defeat your jump.

IMTU I take the middle road, jump is common and safe and required to keep the gears of the 3I turning.

But yeah, in-system traffic is vastly under-explored in the OTU. Now that we’ve got new rules to develop solar systems in more detail I hope we’ll see more attention paid to the belters and miners and scientists that work those areas and the ship traffic that services them. Even super generic stuff like ‘belter colony in the rings of Orbit 7 gas giant’ or ‘floating mining colony in the upper atmo of Orbit 2 gas dwarf’ or ‘surface expedition on Orbit 4 thin atmo world’ suggests there’s ships moving to and from the Mainworld and contributing to its economy and influence. I think all of these endeavors would take advantage of orbital mechanics and have dumb/guided cargo launches, plus routine maintenance/resupply vessels and occasional special couriers. Whether these are jumps vs maneuver drive trips depends on the size and structure of the solar system itself.

 

[Arkathan]

Matt has said (somewhere recently) that the first forays into Merchant Prince territory would be fleshing out belter mechanics.

 

[Condottiere]

Profit margins and shareholder value.

 

[WHULorigan]

. . . if you’re referring to T5’s Jump Lines and so forth, I do not dig that stuff. Another undercooked idea about how the universe works. If these ideas were fully implemented in the OTU interstellar commerce would be considerably reduced, which is anathema to what the Third Imperium is. We went from ‘Jump is exotic and Travellers are rare’ to ‘Jump is as common as international flights’ to ‘Jump is weird, you might end up back where you started a week from now.’ In-system jumps would be basically non-existent because as you say, any random object could defeat your jump.

I like the jumpline obstruction (shadowing /masking, etc) concept, probably because it appeals to the "Physics" side of me (the implied nod to some form of higher-level Quantum Mechanics and [Hyper-]General Relativity).

But it shouldn't be nearly as much of an issue jumping system-to-system as an in-system jump, since unlike most in-system jumps which lie within the local ecliptic plane, jumping system-to-system is in large-scale 3D (regardless of the concept of the "Jump-plane", whether you accept that concept or not), and any destination system is very likely to lie along a free-space trajectory outside the ecliptics of either the originating or destination system. Still a small chance for an obstruction, but much more unlikely.

YMMV of course.

 

[Condottiere]

For hardware, you can't currently optimize for factor/zero.

In astrogation, the technical term would be no brainer, since for all intents and purposes, you can see where you're going in real time.

 

[tytalan]

You keep arguing that an M-Drive is better in all circumstances.
It is not.
You have found a shiny hammer and every problem is now a nail. This is the same issue Truman had in WW2.
I am merely disabusing you of that logical fallacy.
You also seem to be ignoring when I tell you that in certain circumstances, you are not wrong.
In other situations, you are.

No I didn’t in fact I said several times there are cases where jump drive is the better option but it’s vastly rarer than you seem to think. As I have pointed out most of the time maneuver drives are faster and more efficient, economic but you keep arguing to use jump all the time. So maybe quit telling me I’m Truman and actually consider what I’m saying