kilemall
SOC-14 5K
Scenario generation sure. But ship design in an economic/opponent doctrine/logistical situation/political objective vacuum makes for a weapons purist tourney fleet design mentality, not the sense of a working fleet.
tankers and refuelling
- Thread starter flykiller
- Start date
Scenario generation sure. But ship design in an economic/opponent doctrine/logistical situation/political objective vacuum makes for a weapons purist tourney fleet design mentality, not the sense of a working fleet.
pendragonman
Absent Friends Margrave
And it is this tourney fleet design philosophy that I object to.
I wonder what tourney fleets would look like if morale was involved, not many are going to go willingly on a suicide ship.
kilemall
SOC-14 5K
A warship is likely going to have armor which is going to be expensive. Using your example of TL 15 10000 tons, equipping it to armor 10 is going to cost 1100 tons and 1430 MCr. A tanker won't have that, if nothing else due to the fuel tankage loss (except for the special stellar fueling type I mentioned before, which is modeled on the Sirius tanker from Imperium).
Hull cost is not as much as you portray, most builders will look to the close structure for partial streamlining for gas giants and flattened spheres for full streamlining, 40% and 20% off respectively.
The reason to pay full price or a 20% premium depends on whether you are up against a heavily meson-gun deployed fleet. Even then, a dispersed structure hull is an option against such if they do not have a significant PA capability- 50% off hull price, but foregoing armor or refueling. I would tend to only use those for carriers in reserve.
A model/9 computer with fiber option is 200 MCr. A large enough craft should have two or more, 10000 tons in a heavy ship environment isn't going to last long enough for a full set of two, perhaps a model/5 backup, call it 268 MCr.
A set of ND and MS costs 70-110 MCr a set, backup priority would depend again on an opposition's doctrine/ship design of relying on nukes or mesons, so yes that part is smaller.
Weapons can be cheap or expensive depending on how far one goes with meson weaponry. A basic package of a baby 1000-ton meson spinal, 7 bays and 20 turrets would seem to be right for our example ship, figuring a mix of 3 PA, 3 missile and 1 repulsor plus miscellany brings our weaponry cost to the 550ish MCr range.
However the real cost of weapons is power.
A power plant 4 on a 10000 ton hull generates 400 EP- not even enough to fire up the spinal weapon. You are looking at a power plant 12 to fire everything without agility, plus fuel.
That is a mite more engineering then Mr. Tanker needs. Fortunately TL 15 miniaturization is easy on the costs and tonnage, 800 tons and 2400 MCr. Lower TLs are much more brutal and costly to get the requisite power.
Power plant total should be looked at in the light of combat agility trading off against power plant/maneuver costs vs. armor.
Likely cannot do both maximum AND have J-4 capacity, so it's not like all the extras I am outlining would be in the same hull, but there will be costs higher then just base engineering plus fiddly costs in weaponry as you characterize the problem set.
You are also skipping over the options I outlined re: cost-effective use of tankers, as opposed to some arbitrary requirement that they are used constantly for every jump to fuel the fleet.
Clearly with TCS most fleets that are designed appropriately should be able to refuel in less then a day and even under combat (hence the High Guard name) organically without need of a specialized force or ship.
But with judicious use of drop tanks/fleet bases and/or fuel dumps, you can enable main fleet moves outside of the risks of normal refueling spots. Avoiding detection, risk of interception during refueling and/or moving through otherwise barren systems can pay off with critical damage to the enemy, possibly win the war.
Worth it, if conditions are right.
Hence, a decision, not an absolute, even with budget limits.
kilemall
SOC-14 5K
Oh, and my design/use philosophy would involve building tankers to around 81% fuel tankage, the idea being to be topped off at fast refuel time and allow for two ships of equal tonnage to be refueled. If one can accept J-2 refuels, make that four ships of equal tonnage for every tanker.
With drop tanks figure most warships should be in the 10-20% fuel use range, enough to get away with organic refueling but require the tanker/drop tank combo for bigger jumps.
Battle riders aren't the only game in town.
With drop tanks figure most warships should be in the 10-20% fuel use range, enough to get away with organic refueling but require the tanker/drop tank combo for bigger jumps.
Battle riders aren't the only game in town.
Without the mechanics of logistics built in to the economic and operational model surrounding the ships, you can't design for the logistics within the combat ships.
Without a fleet train as a first class concept, you economic model is simply survival of the fleet.
In fact, it's quite difficult to come up with solid doctrine until things like Kuiper/Asteroid belt refueling capabilities are defined. Why worry about gas giants if I have a different source of fuel. Why worry about tankers if I have guaranteed fuel. If the fleet can reliably "live off the land", it changes the dynamics of strategic movement quite a bit. My fleet train can be spare parts on each ship, or dedicated freighters that can simply linger behind the fleet and jump if there's breakthrough.
If the only way to "live off the land" reliably is via Gas Giants and Planets, then those are much more defendable, and make advance potentially more expensive if you have to fight your way to refuel (thus perhaps making it worth the money and time to bring fuel without -- i.e. tankers).
Starfire handles this part pretty well, with their use of cargo stores and supplies for ships combined with ship carrying repair facilities that can be used in the field, plus the idea of Fighters being broken down and stored as cargo, along with higher density quarters for replacement crew for such fighters. But fuel isn't a strategic resource per se in Starfire.
But, the basic point, without a solid foundation in the mechanics of supply, you can't really design anything.
I dunno. How many dT in spares do I need to cart around? Extrapolated, how many dTons of machinery do I need to have to handle ship maintenance? How many for repair? How much food and life support stores do I need to bring, how long do they last?
If my Tigress throws a muffler bearing and breaks the jump drive, what do I need to do to get the ship back? Bring a drive to it? Build a 700KdT tug to bring it home? Can I build a shipyard in the field around my broken Tigress? How long does that take?
Depending on the details, at some threshold, it will make sense to have a Fleet Repair ship with spares, techs, and gear to fix vessels. Maybe 1 ship to help manage 10 or 20 smaller (sub 5K) ships. Larger ships probably have the rooms to spare bring this task internally.
As for jump capable 7-11's, that depends on mission durations and store requirements.
So, first, it needs to be solid enough to determine whether we should bother at all. If I simply have to allocate 1% or 20dt of space (whichever is greater) to a ship to cover all of this, then, ta da -- there's my mechanic, and it's all done (And all of a sudden I have a bunch of 120dt Scout ships flying around). I pay the "operations tax" on all my ship designs and move on. As the mechanics get more and more detailed, the tax gets more and more complicated (up to, and including building and provisioning an entire fleet train that must rendezvous at regular intervals with my fleet).
To me, the day to day operations issues of spares and bolts and duct tape are uninteresting, as I believe it is simply a small tonnage tax one way or the other.
It's the fuel problem that I find more interesting, as it has the possibility of a wider ranging affect strategic fleet movement and assault doctrine.
Condottiere
SOC-14 5K
For engineering problems, you may want a frosty Scottish engineer, ah, on standby.
Jump into a system at J(n–1), tanker jumps to an oort object of same system, has ready refuel after a week. If the battle goes well, the tanker gets sent a scout. If not, the fleet retreats by blind J1 to where the tanker sits, and refuels to J1 elsewhere. Perhaps even J2, if sufficient tankerage is available.
It provides an escape option.
Likewise, with a J4 fleet and a J5-6 gap... J2 CP/EHJ out, refill from tankers, J4 on... tankers return to base and refuel, and go wait at the CP.
| Week | Wk 0 | Wk 1 | Wk 2 | Wk 3 | Wk 4 | Wk 5 |
| Fleet | At A | Jump to CP | Jump to B | Return to CP | repair | at B |
| Tanker | at A | Jump to CP | return to A | return to CP | Repairing/Refuelling Fleet | Return to A or on to B |
like it, love to have it, but unless the "fleet" consists of small-stuff I don't see how this can actually work unless half the "fleet" is tankers.
(a separate issue is mass fleet refueling in the oort cloud. if this is enacted then there will be no limit whatsoever to "secret bases", forward bases, and overwatch bases. individual star systems will become small galaxies themselves, with the inner system like a mousehole surrounded by waiting cats.)
Quite right. The moment a hostile force jumps in the clock is ticking. If it is assumed that the signature of exit from J-space will eventually be automatically be seen by locals, then the hostiles need to refuel adapt so they have more tactical options than "die in place" if any impending action doesn't go their way.
If it isn't assumed that the jump signature isn't automatically observed, there's a bit more time, but anyone who bases their ops plan on a foundation of hope is probably Mia-matched for their role in the X5 Plans Branch
That proposal sounds like a great basis for a scenario offering all sorts of opportunities for tactical innovation & heroics. The consequences of the fleet train being junked would likely be catastrophic!
That'd be a planning risk a commander would have to be willing to accept.
Think of it in terms of a car trip though. You're going for a drive. You know that there are fuel stations at your destination, but you don't know if you're going to be able to use them. It's likely, but not certain. Do you take extra fuel with you, or risk the tongue-lashing you'll definitely get from the Minister of Finance & War if you come-a-cropper?
Note that the oort is 5000 to 100,000 AU... 27 to 555 Light days out. Even if the flash is significantly visible, the tanker in the oort won't be seen for 4 weeks...
A significant KBO can be plenty of fuel, too.
As for the J2+J4 approach... a J4 tanker carries about 25% hull in surplus fuel... an extra J2... But in normal use, it doesn't fill the fleet units from stored; it fills from local resources, and speeds up the process for other ships. When used for a remote op, it's only providing fuel to equivalent tonnage, and then only replacing the J2 used to get to the CP.
One tech not used in Traveller, but that should be, is externally expandable fuel cells. (Like internal collapsibles, they should take extra tonnage. Probably 2%, rather than the 1% of internals) Major Fleet Tankers should have these.... And use them for storing up up to 3x or even 4x their own volume in external balloon tankages.... And then sit, waiting for the fleet, with enough to totally refuel the fleet, deflating the bladders.
Also note: The tonnage of support vessels probably should total at least 25%, and possibly 50%, of an assault force's total tonnage...
When you need tankers to get from A to B, no.
Simply put, it takes a few hours to transfer fuel; it takes a few days to gather it and refine it. If using expandable external tankage, a tanker can process several times its own tonnage, in a matter of hours, and jump away.
I mean, really, it's pretty self evident to me the hows and whys, and it's BASIC seapower doctrine. You always want a nearby retreat location... and jumping in is always risky. So, you want to retain 1J1 fuel jumping in, and have a refuel point within that range. And you want to minimize time there for the retreat.
If you manage to take the system, you sent a scout, instead of the fleet, and have the tanker meet up at the oort CP for the next system.
It's just basic operational tactics of the type A.T. Mahan envisaged. Only stars instead of islands.
And the light lag means that, if no ships return, and no scout, you ca jump out before you're detected out there.
Note also: hopping oort object to oort object, one can cross deep into a sector... and the oort clouds, presuming they exist for even most systems, make borders impractical to enforce...
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