OTU Only: A Funny Thing Happened on the Way from Collace

[Grav_Moped]

Strictly by RAW, no, but by the same logic LBB2 ships wouldn't be able to use drop tanks. I think the demountable tanks in TTA disagrees with that.

Turrets are supposed to be fungible, and at least the simple turrets are obviously the same in LBB2 and LBB5.

Plasma and Fusion Gun turrets are 2 tons. PartAccs are 5Td barbettes at TL-14, 3Td turrets at TL-15. Problem is they take 5 EP in either case...

Particle barbettes are nothing special, fusion guns inflicts size criticals on small ships (in LBB5 combat at least).

Particle Accelerators get to use the Radiation Damage table. Now think about what a Crew-1 result on that table means... :devil: Yeah, can't get there without a spinal in LBB5. Still...
More to the point, consider how much it costs to repair a Weapon-3 (how many lasers does that take out?) or Computer-2 hit.

A critical destroys the hit system, necessitating replacement. A pirate risks tens of MCr in repairs by attacking a ship with a fusion gun.

Spacecraft combat is a very expensive hobby.

Very true.

 

[Grav_Moped]

Or more probably no-one bothered to consider it. The X-boat was defined using LBB2'77 and never revisited.

The Far Trader was only redesigned for LBB2'81 when it was used in an adventure. The X-boat was never looked at in detail again.

This is the most useful answer from my perspective. If it works by fiat, the explanation is left to the referee's discretion.

Maybe it's magic, maybe it's out of HG, maybe it gets all of its Jump fuel from the tender, maybe it only needs one week of fuel.
They didn't say, so any of these could be true. Perhaps they all are, in different parts of the universe.

 

[Grav_Moped]

This is the most useful answer from my perspective. If it works by fiat, the explanation is left to the referee's discretion.

Maybe it's magic, maybe it's out of HG, maybe it gets all of its Jump fuel from the tender, maybe it only needs one week of fuel.
They didn't say, so any of these could be true. Perhaps they all are, in different parts of the universe.

And that's the answer.

TL-10&11 (LBB2): 50Td fuel (J4 with only 7 days PP fuel), minimum databanks, half stateroom, and risks having to run on batteries for up to 16.8 hours if the Jump runs longer than average. Misjump is very likely lethal, even if ship emerges intact. (A rare 1 or 2-week-long misjump may be survivable, batteries won't last beyond that.)

TL-12 (LBB2): 40Td fuel, larger databanks, normal quarters, tender acts as drop tanks. Misjump is lethal if it lasts longer than 4 weeks, even if ship emerges intact. (1 week on batteries, only slightly more than 3 weeks PP fuel remains at start of Jump because up to 10Td fuel is used after tender disconnects during the Jump fuel burn.)

TL-13&14 (HG): 44Td fuel, even larger databanks, second stateroom for passenger or just elbow room for the pilot. All but the longest-duration misjumps are survivable if the ship emerges intact, and it might even be possible to hold out for a full six weeks in Jumpspace.

TL-15 (HG): 44Td fuel, full 13Td databanks, second stateroom as above. This is the canonical XBoat, 5 TLs after its introduction. Misjump results as TL-13&14, above.

 

[Grav_Moped]

Survival Protocol

There's probably a contingency plan for misjumps.

As soon as it's clear that a misjump has occurred (Jump hasn't ended within 185 hours), the pilot gets into his vacc suit, attaches the Emergency Fast Pod to it, and plugs into the ship's power supply.

The Emergency Fast Pod incorporates a week's worth of hydration/nutrient fluid (at normal metabolic rate), four or more doses of Fast Drug and two doses of Fast Drug Antidote in an automated sequential autoinjector. (Note that Fast Antidote is TL-12, and might not be included in Emergency Fast Pods made at TL-9 through -11.)

The first dose of Fast is administered after a short delay for the pilot to get comfortable.

When it takes effect, the ship shuts down all power except a passive radio receiver and a microcontroller so all remaining power can be used keep the vacc suit warm.

When the microcontroller detects that it the ship has left Jumpspace, the Fast Pod administers the first dose of Fast Drug Antidote. (If Fast Drug Antidote is not available, this process is automated and the pilot remains under Fast.) At this point, the ship's passive sensors power up to permit the pilot to determine his location if possible, and a low-power emergency beacon begins transmitting. If the Jump exit point is in an inhabited system with spaceflight capability, the pilot may elect to use a higher-powered radio to signal for assistance.
Otherwise, the pilot has a drink of the nutrient fluid and self-administers another dose of Fast Drug. The remaining three doses are auto-administered at 2 month intervals after the pilot has had a chance to "eat". If the microcontroller detects the XBoat's airlock being opened, it signals the Fast Pod to administer the second dose of Fast Drug Antidote (if available) so the pilot can greet the rescuers.

If not rescued by the time the last dose of Fast Drug wears off about six months after the misjump (and with the ship's batteries finally running out), the Fast Pod signals the vacc suit to euthanize the pilot by replacing the suit's oxygen with nitrogen.

If the ship has fuel to hold out longer, provide more doses of Fast Drug and periodically restart the power plant to recharge the ship's batteries.

It's probably too expensive to provide this for more than a single crewmember.

A simpler solution is to add a low berth powered by a radioisotope generator, but that would occupy a half d-ton that the XBoat doesn't have to spare.

 

[mike wightman]

And that's the answer.

TL-10&11 (LBB2): 50Td fuel (J4 with only 7 days PP fuel), minimum databanks, half stateroom, and risks having to run on batteries for up to 16.8 hours if the Jump runs longer than average. Misjump is very likely lethal, even if ship emerges intact. (A rare 1 or 2-week-long misjump may be survivable, batteries won't last beyond that.)

TL-12 (LBB2): 40Td fuel, larger databanks, normal quarters, tender acts as drop tanks. Misjump is lethal if it lasts longer than 4 weeks, even if ship emerges intact. (1 week on batteries, only slightly more than 3 weeks PP fuel remains at start of Jump because up to 10Td fuel is used after tender disconnects during the Jump fuel burn.)

TL-13&14 (HG): 44Td fuel, even larger databanks, second stateroom for passenger or just elbow room for the pilot. All but the longest-duration misjumps are survivable if the ship emerges intact, and it might even be possible to hold out for a full six weeks in Jumpspace.

TL-15 (HG): 44Td fuel, full 13Td databanks, second stateroom as above. This is the canonical XBoat, 5 TLs after its introduction. Misjump results as TL-13&14, above.

You missed the actual OTU version from your list namely the TL10 Jump 4 40 tons of fuel version that actually exists in the setting as published.

 

[Grav_Moped]

You missed the actual OTU version from your list namely the TL10 Jump 4 40 tons of fuel version that actually exists in the setting as published.

That's the TL-12 version that uses the tanker as a drop tank.

If you can do it without a powerplant and at TL-10 (no Drop Tank Jump Caps), then you're in a '77-rules universe and the rest is moot.

 

[mike wightman]

The OTU was built with the 77 rules and then modified over the years as further rule books and revisions of rule books came along. The underlying setting remains though, and in that setting xboats are TL10 jump 4 with 40t of fuel.

 

[whartung]

Yes, perhaps, but that was not really defined in CT. CT only spoke of worlds and stars preventing jump.

But T5 refined it to being within 100D of anything.

Actually, according to the T5 ruling, you only have to be outside the 100D of the tanks (since the tanks aren't jumping, the ship is).

At the end of a very brief period (less than a few minutes), the jump drive capacitors have been charged to capacity. Under computer control, the energy is then fed into appropriate sections of the jump drive and jump begins.

And then there's the jump capacitors.

How big are they? How long will they hold a charge? Clearly they can hold a charge "for a few minutes" since...they're being charged. How long after that? Maybe when the capacitors are full they start to leak. Ok, then what if I have twice as much capacitor capability? What if I over charge them and let them leak while the fuel shuttle gets safely away?

I'm sure a J6 100K ton freighter would be much happier with a 6,000 ton jump fuel load than a 60,000 ton jump fuel load. If the freighter wants another 10% capacity, it needs 25% more ship to carry it.

At scale most any efficiency is worth taking. The singular expense of jump is the time it takes. As long as the efficiency gained is cheaper than another entire ship and its crew, it's likely worth taking.

 

[BRover]

This is the most useful answer from my perspective. If it works by fiat, the explanation is left to the referee's discretion.

Maybe it's magic, maybe it's out of HG, maybe it gets all of its Jump fuel from the tender, maybe it only needs one week of fuel.
They didn't say, so any of these could be true. Perhaps they all are, in different parts of the universe.

Yep. I, personally, like the Tender feed--or might as well use a Drop Tank with attached rocket. (That way, a slight mod allows a J-6 upgrade with a bigger drop tank, much more elegant than a 2000 ton courier.)

Aside: In MTU, the X-boat was designed by an efficiency expert*, who reasoned that, if you were planning on building 1000s for a network across the Imperium, even minor savings add up. So she designed it as a near-optimal cylinder, 6 m diameter, 12 m high. Four decks, each 25 dTon. That way, 6 fit into the XT's bay--6 "cans" in a "six-pack." And, originally, the J-6 version required a 25 dTon Drop Tank, so four could replace one "can." All very neat--until the revision that needed a Power Plant came along. I also had smaller XT-like ships, for four or even two X-Boat capacity, for outlying or branch route stations. It was a fun design for a more complete system.

*She was never accused of having a poetic soul. More the artistry of an accountant.

 

[Grav_Moped]

But T5 refined it to being within 100D of anything.

Actually, according to the T5 ruling, you only have to be outside the 100D of the tanks (since the tanks aren't jumping, the ship is).


And then there's the jump capacitors.

How big are they? How long will they hold a charge? Clearly they can hold a charge "for a few minutes" since...they're being charged. How long after that? Maybe when the capacitors are full they start to leak. Ok, then what if I have twice as much capacitor capability? What if I over charge them and let them leak while the fuel shuttle gets safely away?

I'm sure a J6 100K ton freighter would be much happier with a 6,000 ton jump fuel load than a 60,000 ton jump fuel load. If the freighter wants another 10% capacity, it needs 25% more ship to carry it.

At scale most any efficiency is worth taking. The singular expense of jump is the time it takes. As long as the efficiency gained is cheaper than another entire ship and its crew, it's likely worth taking.

More Fun With Capacitors... (Not OTU, more of a thought exercise.)
You don't need Pn=Jn to Jump, you only need Pn=Jn/2.
What you need is 3 sets of capacitors in addition to the ones in the Jump Drive. These each hold 1/4 of the 2EP per MJn needed to power the Jump Drive (aside from its own fuel burn, of course).

Basically, charge capacitors in turn, and roll the ones that "time out" after two turns into empty capacitors. It looks like this:

Assume ship needs 4EP to jump (Type S, J2 at Pn 1: 1EP/turn)
EP with an asterisk is in second turn in capacitor and must discharge at end of turn.
Zapping is capacitor being used to charge another capacitor.

Turn    Powerplant     Bank 1       Bank 2     Bank 3    JumpCaps
  1     charges#1      1EP           --         --          --

  2     charges#2      1EP*          1EP        --          --
End of 2               zaps#3        1EP        1EP         --

  3     charges#1      1EP           1EP*       1EP         --
End of 3               1EP        zaps jcap  zaps jcap      2EP

  4     charges jcap  zaps jcap        --        --         4EP and Jump.

This assumes no loss in charging one capacitor from another, of course.

 

[AnotherDilbert]

But T5 refined it to being within 100D of anything.

Quite, but that hardly changes how the CT'81 version worked.

And then there's the jump capacitors.

How big are they?

LBB5 says:

The jump drive capacitors mass .5% of the ship's mass, per jump number; for example, a drive capable of jump3 will include capacitors equal to 1.5% of the ship's mass.

How long will they hold a charge?

I have no idea. LBB5 lets you use them to store Black Globe energy indefinitely.

 

[AnotherDilbert]

The OTU was built with the 77 rules and then modified over the years as further rule books and revisions of rule books came along. The underlying setting remains though, and in that setting xboats are TL10 jump 4 with 40t of fuel.

No, the CT'81 version is vague, e.g. TTB:

Express Boats: The primary means of interstellar communication is the physical transport of messages by a jump-capable ship. Within the Imperium, the method is called the express boat system. Small, fast, information carrying ships are specially constructed to make large jumps and carry data for retransmission.

The X-Boat was defined for CT'77, but never revisited, unlike e.g. the Far Trader or the Gazelle that were redesigned. That leaves them basically undefined for CT'81, just as they were in MT (IIRC).

 

[AnotherDilbert]

Basically, charge capacitors in turn, and roll the ones that "time out" after two turns into empty capacitors. It looks like this:

Why would capacitors "time out"? That is not specified anywhere?

 

[Grav_Moped]

Why would capacitors "time out"? That is not specified anywhere?

I assumed capacitors can't hold full charge for more than two turns or else "something bad happens", as the explanation for why a Jump requires the Jump Capacitors to get their power in two turns or less.

There is no mechanism in the rules for them to self-discharge. Therefore, whatever energy goes into them stays there unless used in ship systems.

This implies two things:
First, this eliminates the reason for the 2EP/MJn power plant input to initiate Jump. Unless a ship has a Black Globe, there would be no reason to not leave the Jump Capacitors fully charged at all times. Then, a jump could happen in 1 turn, limited by the ability of the Jump Drive to process the fuel.*

Second, for combat (or other very short duration use) it's cheaper at most TLs to carry additional power as capacitors than as power plant+fuel.
1EP-Day (72 EP) (EPD) requires 2Td of capacitors and costs MCr8. At TL-15, 1 EPD needs Pn-1 at 2Td (1 ton fuel, 1 ton power plant) and MCr 3.

For 2 EP over 12 hours, the TL-15 power plant + fuel is MCr6 and 6 Td.
For 4 EP over 6 hours, the TL-15 power plant + fuel is MCr 12 and 12 Td.
That's still just 2 TD of capacitors at MCr 8.

6 hours is 18 combat turns. And they provide the option of trading duration for surge power on demand.

Why hasn't this been used in canon?

This sort of requires reading between the lines since it's not really discussed. Jump Drives include 18EP/MJn of capacity, but need 2EP/MJn to initiate Jump. This might imply that they are normally charged up with 16EP/MJn and can store that much indefinitely.** This would suggest that ships with Black Globes (and only those ships) normally don't leave their jump capacitors charged, to save capacity for absorbed energy.

But then, why can't those EPs be used for weapons, shields, or agility instead of Jump?





* ... and we're this close to '77 rules again (no powerplant for the Jump Drive)...
** On the other hand, the other 16 EP might be coming from the Jump Drive during its fuel burn. As a separate matter, it suggests that capacitors can only hold 32EP/Td for extended periods. If so, adjust the math in the preceding section accordingly.

 

[whartung]

Why would capacitors "time out"? That is not specified anywhere?

Because capacitors naturally discharge. These are very large capacitors, holding "lots" of energy. Maybe they're "very leaky".

I assumed capacitors can't hold full charge for more than two turns or else "something bad happens", as the explanation for why a Jump requires the Jump Capacitors to get their power in two turns or less.

There is no mechanism in the rules for them to self-discharge. Therefore, whatever energy goes into them stays there unless used in ship systems.

This implies two things:
First, this eliminates the reason for the 2EP/MJn power plant input to initiate Jump. Unless a ship has a Black Globe, there would be no reason to not leave the Jump Capacitors fully charged at all times. Then, a jump could happen in 1 turn, limited by the ability of the Jump Drive to process the fuel.

Second, for combat (or other very short duration use) it's cheaper at most TLs to carry additional power as capacitors than as power plant+fuel.
1EP-Day (72 EP) (EPD) requires 2Td of capacitors and costs MCr8. At TL-15, 1 EPD needs Pn-1 at 2Td (1 ton fuel, 1 ton power plant) and MCr 3.

What it implies is that if the Jump comes from capacitors, then, perhaps, "anything" can charge those capacitors: fusion plant, fission plant, antimatter plant, solar panels, a really long extension cord from the starport, frozen watch on bicycle generators.

If the capacitors are "leaky", then that can explain why they need to charged "so fast" (i.e. not just a fusion plant, but one requiring lots of fuel for power and coolant). You have to overcharge them faster than their leak rate and then fire them before they discharge below the viable point. It also can explain why you can't charge externally (i.e. drop tanks, fuel shuttles, etc.) since they leak so fast that they become the constraint which dictates the speed of the jump process.

But that than suggests that a ship could be over-provisioned, and overcharged to buy them some time during the process.

See the trick is hear it not to necessary explain why things alternatives like this etc. are "impossible", but why they're uncommon. Why are they "not worth it", etc.

The "rules" are a projection of the universe (which is why exceptions exist), not the other way around.

"Why don't ships do XXX?" "Cuz they don't, they haven't done that since year 375...since that was way before my time, I don't know why they stopped."

 

[Grav_Moped]

I was thinking that the "something bad" was more on the explodey side than the leaky side, but self-discharge is a reasonable explanation.

On the other hand, they apparently don't significantly self-discharge within the time frame of a typical HG battle, or there would have been some game mechanic to cover that.

 

[BRover]

I was thinking that the "something bad" was more on the explodey side than the leaky side, but self-discharge is a reasonable explanation.

I'd think that, given the scale of energy stored, "leaky" (if fast enough to matter) would quickly escalate to "sparksen poppen" and then "explody." :xh:

 

[Grav_Moped]

I'd think that, given the scale of energy stored, "leaky" (if fast enough to matter) would quickly escalate to "sparksen poppen" and then "explody." :xh:

That's a bad thing, right?




(1EP=83.3 MWh. That's ONE EP. Ouch.)

 

[Grav_Moped]

...
But that than suggests that a ship could be over-provisioned, and overcharged to buy them some time during the process.

...

... and we're this close to LBB2'77 rules again.


(No, I don't prefer them. It's just funny how other rules keep coming around to that if you look at them sideways for long enough. And in fairness, I could easily be talked into a house-ruled ATU where Pn=Gs or Pn=Jn whichever is higher, but minimum of 1.)

 

[BRover]

I'd think that, given the scale of energy stored, "leaky" (if fast enough to matter) would quickly escalate to "sparksen poppen" and then "explody." :xh:

That's a bad thing, right? <:rofl:>

(1EP=83.3 MWh. That's ONE EP. Ouch.)

It's only bad if you're sensitive. Like--living sophont, or electrical-based (robots, vehicular control systems)?

Otherwise, enjoy the fireworks! :coffeegulp:

Ooooooohh--shiny!