Proneutron
SOC-13
Which is powered by the jumpdrive. Sorry but no cigar.
That's like saying the jet is propelled by the exhaust coming out the nozzle but you don't need the spinning turbine in the engine to keep it coming out. :coffeesip:
CT Only: Jump Torpedoes
- Thread starter Timerover51
- Start date
Which is powered by the jumpdrive. Sorry but no cigar.
That's like saying the jet is propelled by the exhaust coming out the nozzle but you don't need the spinning turbine in the engine to keep it coming out. :coffeesip:
mike wightman
SOC-14 10K
The jump drive is to open the rift into jump space. The jump field that protects the ship is something to do with the hull cable network and the lanthanum coils.
Remember that we are talking about a jump torpedo that predates a lot of the rules that would come later - even the MWM article on jump drives.
At the time of the 77 CT rules where jump torpedoes are a thing the minutiae of the jump drive had not been filled in - all that is mentioned is the hull grid and lanthanum coils from early library data.
So it is possible that the jump torpedo, rather than being able to jump all by itself and thus need all that jump fuel etc. consists of nothing more than the grid and coils necessary to protect it from jump space, plus the usual stuff such as a battery, comms, a computer...
Last edited:
OTOH, if Virus is an option, it could survive on a Jump Torp quite nicely, assuming there is sufficient data capacity.
The main consequence is that unless you've got another ship with you or your ship is big enough to carry a Scout/Courier, you're on your own -- the cavalry isn't two weeks away, it's at least 41 months away at lightspeed (if your signal is noticed at all).
And if you're in combat, it means taking at least 100Td of ship (and one turret) out of the fight to get the message out. That's if it has jump fuel... and if you jumped into the situation, it probably doesn't.
Unless you're handwaving it, the smallest you could build one under HG is maybe 6Td and about MCr25.5 (and that takes a bit of rules-twisting). It'll do Jump-1 (computer-limited). See my "The Littlest Starship" thread for a slightly more capable unit. It doesn't cost that much less than a Type S, and only does Jump-1. To get Jump-2 out of it, add a ton of fuel and MCr18 (to upgrade to a Model/3bis computer from Model/3), and then it costs almost half again as much as a Type S.
Doesn't make much difference to the XBoat network. What it does is to make calling for help far less costly and less dramatic. (There are minor effects on reconnaissance techniques as well.)
Another thing jump torpedoes do is break the 100Td minimum rule. It's arbitrary, but one key issue with it is that if you're using LBB2 the maneuver drive formula breaks below 2G in 100Td (Size A). You won't see this unless you try to use LBB2 to make small-craft sized starships (or try to figure out the specs for a 1G maneuver drive in 100Td).
Still another thing they do is break the 20-ton/2% minimum bridge size rule. This rule is a key element of penalizing smaller starships (the LBB2 power plant fuel by Pn rather than Pn and ship tonnage is the other element).
And if it's missile-sized rather than minimal small craft sized, it's almost certainly breaking the "computer Mod/n = Jn" rule.
Last edited:
Some possible absurdity:
1. It doesn't actually need anything. Fire up the ship's jump drives and kick the torp into the hole you just made in space.
2. It doesn't need much fuel. Use drop tanks. Heck, use a fuel hose from the launching ship's tanks and give the torp a good hard kick just before the Jump Drive lights off (or run away from it).
3. It doesn't need a computer. Run Generate and Navigate, record the results and load 'em into an iPad built into the torp.
I'm only serious about point 2.
But yeah, under '77 rules you could pretty much say it only needed to be a mini jump drive, 10%/Jn fuel, and a hand computer to run Jump-n.
HG2 lets you comply with all starship requirements except the 100Td minimum in 30Td.
TL9, J1/1G/Pn1 (1Td each), 20Td bridge, Mod/1 comp, 1/2 stateroom, 4Td fuel.
MCr12.165 as flattened sphere, w/o class discount.
Minimum drive size is 1Td but fractional sizes above 1Td are allowed (HG2, p. 34).
- in 30Td, 1Td jump drive (3.33...%) could be J-2 (only J1 in this case).
- in 30Td, 1Td maneuver drive can only do 1G.
- in 30Td, 1Td TL9 power plant is Pn-1 (1.11...)
Minimum power plant fuel is 1Td (HG2, p. 34).
Minimum starship bridge size is 20Td (CT, passim). Cost is by ship tonnage (HG2, p. 27).
Jump fuel is 10%*Td*Jn; 3Td (ibid).
2Td Half-stateroom allowed by TCS (p. 15), while only implied in LBB2 and LBB5.
J2/1G is probably possible in 35Td, but the Jump Drive and power plant will need to be enlarged by a fraction of a ton each, in addition to the additional jump fuel requirement and upgrading to a Mod/1bis.
Last edited:
mike wightman
SOC-14 10K
No, it is not like saying that at all. It's like saying you need to continually input energy to maintain the magnetic field around a steel core that has been through a solenoid - hint you don't. (By the way there is a big flaw in your jet engine analogy but I will let that one go)
Point me to the rule that states the whole jump drive is needed to maintain the jump field please. And make sure that rule is pre1981 revision since we are discussing something that can not exist post revision and was written out of the game.
You are arguing based on rules that do not exist at the time when jump torpedoes were a thing- something I am also guilty of since the idea of a hull cable network isn't mentioned until the article.
Nowhere in the Traveller corpus is the jump drive fully detailed until MWM jumpspace article.
The earliest mention of the inner workings are the final cost of a spaceship rather than a starship is half (so why is the hull of a spaceship cheaper than a starship?) and that lanthanum coils are part of the inner workings.
Jump drives don't need a separate power plant, and all the jump fuel is used when you jump. We are also told the power plant less x-boat maintains its jump field using batteries.
Last edited:
mike wightman
SOC-14 10K
I quite like this 30t runabout idea and actually may have a good use for it in a scenario I have in mind...
Thanks! It could be a drop-in replacement for a carried Ship's Boat or Slow Boat.
Even going slightly larger can provide significant performance improvements, but this is as small as it gets without breaking anything except the 100Td rule.
Condottiere
SOC-14 5K
You can attach a seventy tonne fuel tank.
You could, but it wouldn't move or Jump.
HG2 needs 2% tonnage drives each for J1 and 1G. This thing uses 1Td drives because that's the minimum HG allows (this from the small craft design rules; in fairness, they weren't thinking about jump drives when they made those rules because you're not supposed to put a jump drive into a small craft in the first place).
It'd work at 50Td (20Td tanks) though, still at J1/1G. Needs 6Td total tankage for J1 and 4 weeks.
The notion that a naval battle squadron doesn't have Scout support is absurd, for all the reasons cited -- it's their only link to the "outside" world.
If a fleet is dragging a tanker squadron along, there's certainly a few 100 spare dTons to shove in a scout or two among the ships of the fleet.
Outside of the tanker squadrons simply existing, there's not much detailed canon that I'm aware of talking about the fleet train. But everything suggests that it exists, that there's means to communicate with the fleet, and that the communication takes time. The actual mechanics of the scouts flitting about is simply not detailed because it is a bunch of detail.
I expect there were hundreds of scouts lingering and flying about during the FFW. Those attached to fleets, those carrying messages to and from admiralty, those hanging in remote systems waiting for the jump flash of invading ships and staying long enough to take a rough count and size estimate, and then rush out the information to command.
Scouts are a cost of doing business for military fleets.
I don't see the existence of a Jump Torpedo changing that "game" one wit. It makes the communications "cheaper", and adds a little bit of capability not existing before, but at the large scale of civilization, it's not a game changer.
I can see an "adventure" ship for sure would like to have a jump drone Just In Case, like a modern adventure hiker or wilderness traveler taking a satellite phone or beacon. A typical Free Trader wouldn't, it's not worth the cargo space.
I was thinking in terms of player-character level activities, not fleet actions. On that level it makes a huge difference. As I said, it means the cavalry is two weeks away, not three and a half (if ever).
The de-canonized canon j-torps in Adv. 4 seemed to be about turret-missile sized, and did not have a listed range or cost. Basically, "you have four of these, it's between you and the ref to figure out what they can do". That's a big deal! A Free Trader could carry one, or a few.
The HG2-derived ones I worked out are big and expensive enough to give a Free Trader pause about the costs. They also involve radically twisting rules (minimum bridge size) to enable them, but so do the (non)canon j-torps from A4.
Those (non)canon j-torps break four major design constraints for Traveller ship building.
1. Starships require a 20Td minimum bridge
2. Jump requires a computer ('77: with CPU to run Jump-n; '81: Mod/n=Jn).
3. Jump requires a powerplant of Pn=Jn (all post-'77 CT rules).
4. Minimum drive size is 1Td.
These affect ship design.
And the existence of j-torps radically drops the cost of interstellar communication. A J2 Scout/Courier is about MCr27. A J4 XBoat is about MCr70. An 800Td J6/1G ship is about MCr563*. A j-torp... is far less expensive than that.
A standard XBoat link with a one boat per day cadence in each direction requires 14 Xboats, at close to a billion credits in ships per link. That's just linking two worlds, and it's part of a chain so there's at least two links out of every world on the route. What do 14 j-torps cost? Why wouldn't you deploy them everywhere? All you'd need for a tender at each end would be a 50Td cutter with a fuel module.
Then there aren't any backwaters.
That breaks things.
*smallest possible LBB2:'81 J6 that's entirely Rules As Written compliant. It's TL15. HG2 lets you do J6 in under 150Td at TL15 (if memory serves, it's about 135Td) without drop tanks.
The de-canonized canon j-torps in Adv. 4 seemed to be about turret-missile sized, and did not have a listed range or cost. Basically, "you have four of these, it's between you and the ref to figure out what they can do". That's a big deal! A Free Trader could carry one, or a few.
The HG2-derived ones I worked out are big and expensive enough to give a Free Trader pause about the costs. They also involve radically twisting rules (minimum bridge size) to enable them, but so do the (non)canon j-torps from A4.
Those (non)canon j-torps break four major design constraints for Traveller ship building.
1. Starships require a 20Td minimum bridge
2. Jump requires a computer ('77: with CPU to run Jump-n; '81: Mod/n=Jn).
3. Jump requires a powerplant of Pn=Jn (all post-'77 CT rules).
4. Minimum drive size is 1Td.
These affect ship design.
And the existence of j-torps radically drops the cost of interstellar communication. A J2 Scout/Courier is about MCr27. A J4 XBoat is about MCr70. An 800Td J6/1G ship is about MCr563*. A j-torp... is far less expensive than that.
A standard XBoat link with a one boat per day cadence in each direction requires 14 Xboats, at close to a billion credits in ships per link. That's just linking two worlds, and it's part of a chain so there's at least two links out of every world on the route. What do 14 j-torps cost? Why wouldn't you deploy them everywhere? All you'd need for a tender at each end would be a 50Td cutter with a fuel module.
Then there aren't any backwaters.
That breaks things.
*smallest possible LBB2:'81 J6 that's entirely Rules As Written compliant. It's TL15. HG2 lets you do J6 in under 150Td at TL15 (if memory serves, it's about 135Td) without drop tanks.
Last edited:
Condottiere
SOC-14 5K
Which is where fleet couriers and the ecks boat network come in.
Proneutron
SOC-13
They wouldn't leave everyday. Just like the Age of Sail. Except on all but the largest, most important Gov world pairs they would be once a week unless some catastrophe happened. For which one spare X-boat would exist. No idea what cannon says on this though.
Amortized over a 20 year ship life span. Not a real issue with planetary economies.
Obviously it's different if all you have is outposts with 100 people on it, but they need external supplies anyways, and can use those supply runs for their base communications. And if they could use so jump torpedoes? Again, IN THE LARGE, not very game changing.
Can jump torpedoes be re-used? I have no idea. If they can't be, perhaps the JT is not a cheaper alternative to the X-Boat network.
Nevertheless whether it's with "cheap" jump torpedoes or an X-boat network, communication is STILL 2 weeks round trip. THAT is the "real cost" of communication, not the infrastructure to move it. The idea of having to wait 2 weeks for, well, anything (lawyers, guns, money...), makes communication very expensive.
Fundamentally, the X-Boat network does not make civilization expensive. The X-Boat network is well worth its costs, whether fronted by the individual systems, subsidized by wealthy systems, paid for by the mega corps. The overall "friction" of the cost of the X-Boat network is low. Making it cheaper would not have a gross impact on interstellar civilization.
Clearly the X-Boat network does not have 100% coverage, even if it's cheap, doesn't mean its necessarily universal. Those systems not directly on the network are serviced ad hoc through mail runs or other less formal mechanics.
If you're using XBoats at all, it's because you want messages to arrive faster than they would by using multiple jumps for the same distance. If you can wait up to 2 weeks to send a message (that is, one created just as the week's XBoat leaves, so you have to wait a week in addition to the week in Jump), you can probably get by with using two shorter-ranged ships instead and take 2 weeks in transit.
Also, apparently the once-a-day thing is standard according to this discussion here. There's a really good analysis of the economics (cost per message) on the last page of that thread.
Also, apparently the once-a-day thing is standard according to this discussion here. There's a really good analysis of the economics (cost per message) on the last page of that thread.
Proneutron
SOC-13
No I use X-boats to have messages go 4 parsecs in 2 weeks time. I don't use X-boats across shorter distances. And it would take a J1 freighter 4 weeks (if it holds enough fuel, longer if it had to "go around") to bridge that distance. Same with a J2 ship. With much more wear and tear on the J-drives.
That an IMTU poll. Not RAW of the 3I. But RAW could be 1/day. I don't know. But X-boats are only on major routes. Mostly J-4 routes.
It's not the poll, it's this quote from post #31 in that thread (top of the linked page):
"The "one boat every 24 hours per link" tempo was hashed out right here years ago. Hans [Rancke] wanted more departures, probably to soak up more of the Imperium's taxes, but the time issues eventually convinced him. IIRC, Robject let us know that Mr. [Marc] Miller considers the 24 hour tempo correct."
Proneutron
SOC-13
That's not RAW. "IIRC" - That's dodgy hearsay on a 3rd party conversation. But, maybe buried in T5 as it would be in there given the time frame mentioned in that post. I DO seem to recall something from decades ago about 1/Day but can't recall source.
