Topics Enjoying 30 Years of Discussion

[G. Kashkanun Anderson]

That's a useful summary.

I suppose Book 2 '77 would make it painfully clear that the Xboat cannot have a Power Plant. Let's try it out.


ONE TRIP?? Does that mean what I think it means?

The assumption, in this particular case, would be about three weeks, I guess. Allow for 3-4 days travel time to get from orbit to 100 diameters and another 3-4 days the other way, plus about 8 days for an extra long jump time, then toss in a few more days for an extra margin of error. Something more specific might be stated elsewhere in the book, though I don't remember seeing it.

(100 tons): STANDARD 100 TON HULL.
  15 tons: Jump drive B (J-4). This fills the engine room.
  40 tons: Jump drive fuel.
  20 tons: Bridge with basic controls, comms, and sensors.
   2 tons: Computer Model/2 (is that enough?)
   8 tons: Two staterooms.

Looks like we still have 15 tons free.
However, the jump drive does fill up the STANDARD HULL's engine room, leaving no room for a power plant.

Yeah, but the standard hull isn't a hard rule for starship construction; it just makes nonstandard designs much more expensive for your Average Eneri to build. And the Imperium is not an Average Eneri contractor. If Strephon tells Gas-Bag that he wants umpteen-thousand of a certain type of ship built, Gas-Bag's not going to come back with a sheepish shrug and a, 'sorry, Streph, we don't do nonstandard designs. Maybe try Vinnie Vargr's Custom J-Rods down in the Dog District; I hear they do good work'.

Or, to be blunter: if the Imperium wants it built, it is a standard design.

No. What borks up the process in the '77 rules is the frankly bonkers fuel requirements given for power plants (10 tons per plant number, regardless of ship size). And anyone who does not think this is bonkers is welcome to explain to me how the exact same power plant (A) requires twice as much fuel to run a 100 DTon Type S Scout as it does to run a 200 DTon Type A Free Trader.

That rule still exists in the '81 starship construction rules, alongside that book's explicit ruling against allowing power plant free starships. Also, that edition was never intended to change any rules so much as clarify those that the '77 rules had unintentionally left fuzzy -- or, at least that's what they said about it at the time that they released it.

High Guard, quite reasonably, would assign two DTons of fuel for both the Sulie and the Free Trader designs. And High Guard is the more explicitly OTU version of the rules. It is, after all, the only ruleset that expressly mentions the existence of XBoats.

 

[G. Kashkanun Anderson]

In '77, it was pretty much explicitly maneuver fuel.

I honestly do not know where you come to this understanding, considering that right above the statement from Robject you are quoting it explicitly states otherwise. To reiterate:

[5] A power plant, to provide power for one trip (internal power, maneuver drive power, and other necessities) ...

Another example is the double fire rule on page 32, which makes a very strong case for ship's weapons being among the 'other necessities' mentioned above:

Double Fire: This program allows a ship to draw excess power (if available) from the power plant, and thus increase the output of laser weaponry. When this program is functioning, a vessel with a power plant rated at least one letter higher than its MDrive (and which has not yet taken damage to reduce the current letter rating to equal to or below the M-Drive letter) can fire a double beam or double pulse with laser weaponry.

 

[Grav_Moped]

I honestly do not know where you come to this understanding, considering that right above the statement from Robject you are quoting it explicitly states otherwise. To reiterate:

Another example is the double fire rule on page 32, which makes a very strong case for ship's weapons being among the 'other necessities' mentioned above:

Construction and fuel use rules. If you don't have a maneuver drive, a power plant (and its fuel) was not required in LBB2'77.
Presumably a '77 XBoat could mount a turret, and put lasers into it. It couldn't use double-fire though.

I suppose basic power (and for weapons, too, rules-as-written) could have come from batteries charged by the jump drive. Or something. It wasn't explained, and didn't matter until High Guard came out.


Non-starships had the same fuel allocation requirement as starships, except for the jump drive fuel.

The extreme case is probably a 100Td hull containing only the bridge, a Mod/1 computer, two staterooms, a triple laser turret, and 70Td of cargo space. Somehow the lasers could still be fired once each per turn, indefinitely.

 

[robject]

I suppose basic power (and for weapons, too, rules-as-written) could have come from batteries charged by the jump drive. Or something. It wasn't explained, and didn't matter until High Guard came out.

Local fusion+ modules could charge the capacitor-like thingies, maybe. Causes other game rule issues.

 

[robject]

[...] the standard hull isn't a hard rule for starship construction; it just makes nonstandard designs much more expensive for your Average Eneri to build. [...]

Or, to be blunter: if the Imperium wants it built, it is a standard design.

[...] What borks up the process in the '77 rules is the frankly bonkers fuel requirements given for power plants (10 tons per plant number, regardless of ship size). [...]

All good stuff. And yet it leaves me scratching my head, because I've missed something about the Xboat's design and I don't know what it is.

Space is so cramped aboard the xboats that they do not even contain maneuver drives.

Thing is, they're not cramped per se. There's just not enough space for the M-drive, P-plant, and P-plant fuel. As you noted, the fuel rules are strange. Maybe we'll get a Book 2 revision.

Anyway, we do have 15 tons free for other things.

 

[Spinward Flow]

Anyway, we do have 15 tons free for other things.

Those 15 tons are already allocated to mission critical systems.

Communications arrays (possibly multiple to multiplex transmissions on multiple frequencies simultaneously) and their power supplies.
Encryption/decryption and data compression resources needed for transmissions and storage.
Extensive data banks to hold all the data.
Heat pumps to keep all that computer power from overheating the interior of the XBoat.

Okay, I'm only kind of joking with that last one, but you get the idea.

 

[Grav_Moped]

Yeah, but the standard hull isn't a hard rule for starship construction; it just makes nonstandard designs much more expensive for your Average Eneri to build. And the Imperium is not an Average Eneri contractor. If Strephon tells Gas-Bag that he wants umpteen-thousand of a certain type of ship built, Gas-Bag's not going to come back with a sheepish shrug and a, 'sorry, Streph, we don't do nonstandard designs. Maybe try Vinnie Vargr's Custom J-Rods down in the Dog District; I hear they do good work'.

Or, to be blunter: if the Imperium wants it built, it is a standard design.

Which, though I absolutely understand the meta-game reason for the Standard Hull mechanic, is why I hate it.
Those hulls need to be standard for some specific ship design, and half of them don't evenly match any possible combination of LBB2 drives. Or LBB5 drives either, for that matter.

No. What borks up the process in the '77 rules is the frankly bonkers fuel requirements given for power plants (10 tons per plant number, regardless of ship size). And anyone who does not think this is bonkers is welcome to explain to me how the exact same power plant (A) requires twice as much fuel to run a 100 DTon Type S Scout as it does to run a 200 DTon Type A Free Trader.

That rule still exists in the '81 starship construction rules, alongside that book's explicit ruling against allowing power plant free starships. Also, that edition was never intended to change any rules so much as clarify those that the '77 rules had unintentionally left fuzzy -- or, at least that's what they said about it at the time that they released it.

The '77 starship/nonstarship powerplant fuel rule was an extrapolation of the (nonsensically nonlinear) fuel rule for small craft.
The '81 adjustment didn't change the formula; instead, it only changed what the required amount of fuel did.
They did change the formula for small craft (by using High Guard quantities and its minimum fuel tank size).

High Guard, quite reasonably, would assign two DTons of fuel for both the Sulie and the Free Trader designs. And High Guard is the more explicitly OTU version of the rules. It is, after all, the only ruleset that expressly mentions the existence of XBoats.

T5 sets it at 2Td per rating # per 100Td (that is, 2Td per EP in High Guard units of measure), though there are some efficiency gains by TL.

 

[Straybow]

Yeah, but the standard hull isn't a hard rule for starship construction; it just makes nonstandard designs much more expensive for your Average Eneri to build. And the Imperium is not an Average Eneri contractor. If Strephon tells Gas-Bag that he wants umpteen-thousand of a certain type of ship built, Gas-Bag's not going to come back with a sheepish shrug and a, 'sorry, Streph, we don't do nonstandard designs. Maybe try Vinnie Vargr's Custom J-Rods down in the Dog District; I hear they do good work'.

Or, to be blunter: if the Imperium wants it built, it is a standard design.

"Standard" should be a design that actually works, not a collection of numbers scribbled down in a beery fog for the first draft of a game. Yeah, pitched that argument a few times. Mine was a bit different though. The broken rule could be a throwback to an earlier era when drives were clunkier. If the Vilani were too hidebound to change the standard, the Rule of Man would have tossed it aside and set a new standard. That's pretty much the reason why the little Terran Confed was able to take on the huge Vilani empire and win.

 

[G. Kashkanun Anderson]

All good stuff. And yet it leaves me scratching my head, because I've missed something about the Xboat's design and I don't know what it is.

Well, I can't be sure, but I think what may be missing here is that the XBoat design is a problematic attempt to force an OTU (High Guard) shaped peg into a Book 2 shaped hole. The clue is in Traders & Gunboats (which, as I mentioned before, is where XBoats were first fully detailed), where the text (page 10) says that they come equipped with Model/4 computers (required under High Guard), while the deck plans specs (page 9) allow for only a Model/1bis computer (all that's required under Book 2).

Just for because, let's build an XBoat using High Guard '80 rules:

Start at TL-13 (the TL at the time they were initially built)
Use a 100 DTon hull (to insure a one-man crew)

1. 15 Dtons Jump Drive 4 (Book 2 model, allowed under High Guard)
2. 8 DTons Power Plant 4 (fuel-efficient High Guard model, required for Jump Drive 4)
3. 44 DTons fuel requirement
4. 20 DTons bridge
5. 4 DTons Model/4 Computer (requirement for Jump Drive 4)
6. 8 DTons two staterooms (Admiralty insisted on VIP courier capability)

Total used space: 99 DTons, leaving 1 DTon for cargo space.

This does, canonically speaking, fit the XBoat's description like a glove.

I admit, it is a bit eccentric to combine a Book 2 Jump Drive with a Book 5 Power Plant, but the rules don't say that you can't do it, and an in-universe explanation could be that Book 2 Jump Drives sacrifice space efficiency for reliability and ease of repair. The Book 2 Power Plant is, conversely, smaller and cheaper than its High Guard equivalent, but this is more than made up for by the fact that it's such a damned hydrogen hog that you can't fit its fuel requirements inside the boat!

Fun Fact #1: At TL-14 you can build a Jump 5 XBoat by 'reverting' to a High Guard Jump Drive, but only at the cost of removing the extra stateroom, and I can see the Admiralty declaring a hard no to that idea.

Fun Fact #2: You can't build a Jump 6 XBoat under any circumstances in High Guard, even at TL-15. At least not until you figure out how L-Hyd tanks work -- which, if you recall the TAS dispatch in JTAS 2, which is exactly why the Imperium was finally able to start upgrading its XBoat network to Jump 6 capability in 1105.

 

[Spinward Flow]

8 DTons Power Plant 4 (fuel-efficient High Guard model, required for Jump Drive 4)

That only works at TL=13.
XBoats are TL=10 (presumably for the Model/4 computer).
A Power Plant-4 drive in a 100 ton starship @ TL=10 under LBB5.80 would be 12 tons, not 8.

Fun Fact #2: You can't build a Jump 6 XBoat under any circumstances in High Guard, even at TL-15. At least not until you figure out how L-Hyd tanks work -- which, if you recall the TAS dispatch in JTAS 2, which is exactly why the Imperium was finally able to start upgrading its XBoat network to Jump 6 capability in 1105.

Well ... you can't do it in a 100 ton form factor.

You CAN do it in a 172 ton form factor though with all internal fuel under LBB5.80 @ TL=15.

• 172 tons
• TL=15 Jump-6 drive = 12.04 tons
• Maneuver-0
• Power Plant-6 = 10.32 tons
• Fuel = 113.52 tons (6 parsecs, 4 weeks)
• Bridge = 20 tons
• Model/6 computer = 7 tons
• Staterooms (2) = 8 tons
• Cargo = 1 ton
• Waste space = 0.12 tons

If however you "break" the power plant fuel formula so as to require only 10 days of endurance at full power (enough for 1 jump plus a 3 days for Tender recovery) rather than requiring the standard 28 days (4 weeks), you only need 35.714% of the standard power plant fuel load.
Net result is a non-drive/non-fuel internal fraction of 24.857%.
For 36 tons of bridge, computer, staterooms and cargo, that means a minimum hull size of 145 tons.

• 145 tons
• TL=15 Jump-6 drive = 10.15 tons
• Maneuver-0
• Power Plant-6 = 8.7 tons
• Fuel = 90.15 tons (6 parsecs = 87 tons, 10 days = 3.107 tons)
• Bridge = 20 tons
• Model/6 computer = 7 tons
• Staterooms (2) = 8 tons
• Cargo = 1 ton
• Waste space = 0 tons

Bump it up to 150 tons and you can get 14 days of endurance out of the power plant.

• 150 tons
• TL=15 Jump-6 drive = 10.5 tons
• Maneuver-0
• Power Plant-6 = 9 tons
• Fuel = 94.5 tons (6 parsecs = 90 tons, 14 days = 4.5 tons)
• Bridge = 20 tons
• Model/6 computer = 7 tons
• Staterooms (2) = 8 tons
• Cargo = 1 ton
• Waste space = 0 tons

Basically you wind up with J6 XBoats that require 3 J4 berths to fit 2 J6 berths in a Tender if using all internal fuel.

The problem is that when you price it out in terms of 40 year life cycle costs ... the 150 ton internal fuel version winds up costing the IISS Communications Office more over 40 years of operational service than using a 100 ton form factor with L-Hyd drop tanks to make up for the remaining fuel fraction needed (especially if the drop tanks can be recovered for reuse, rather than being destroyed at jump!). The 100 ton form factor is also places far less "demand loading" on Tenders for refueling logistics (either taking the Tender off station or assigning a Scout/Courier a fuel tanker for fuel run transfers so Tenders can remain on station) in order to sustain operations.

So it CAN be done inside of Hull Code: 1 ... but you're right that it's difficult to do within 100 tons without resorting to external fuel fraction.

 

[robject]

Well, I can't be sure, but I think what may be missing here is that the XBoat design is a problematic attempt to force an OTU (High Guard) shaped peg into a Book 2 shaped hole. The clue is in Traders & Gunboats (which, as I mentioned before, is where XBoats were first fully detailed), where the text (page 10) says that they come equipped with Model/4 computers (required under High Guard), while the deck plans specs (page 9) allow for only a Model/1bis computer (all that's required under Book 2).

After reviewing Book 2 '77, Book 2 '81, HG1, and HG2, I've decided that:

1. The Xboat was designed alongside High Guard 2nd edition.
2. The 1977 Book 2 jump drive assumption was pulled in as a "custom" jump drive, which is allowed on p22.

Custom-built drives must be produced and installed while observing restrictions as to tech levels and interior space.

...which is said almost in the same breath as the immediately following sentence:

It is possible to include standard drives (at standard prices) from Book 2 if they will otherwise meet the ship's requirements;

I note, wryly, that they don't limit the statement to a particular version of Book 2.

 

[mike wightman]

The x-boat is TL10 which is in breach of the HG drive TL paradigm and is therefore only legal under LBB2 - which raises the question yet again of how you can have letter drives and % drives with contradictory TL paradigms in the same universe...

 

[whulorigan]

I note, wryly, that they don't limit the statement to a particular version of Book 2.

Becuase HG2 was published in 1980, when there was only the 1977 version of Book 2.

 

[whartung]

and is therefore only legal under LBB2

I dunno, seems to me it's illegal under every rule set, otherwise the 30 years discussion around them would be long settled.

 

[Spinward Flow]

which raises the question yet again of how you can have letter drives and % drives with contradictory TL paradigms in the same universe...

Easy.
Standard drives that get built to spec "regardless of hull" ... or ... custom drives that get built to spec "for specific hulls" is the answer you're looking for.

LBB2 standard drives are "same drive yields different performance in different hulls" and you just need the tech level to build the standard drive designs.

LBB5 custom drives tend to be more tonnage efficient below 1000 tons of hull, but require greater tech level to produce "non-standard" drive designs custom built for each hull.

 

[Grav_Moped]

I dunno, seems to me it's illegal under every rule set, otherwise the 30 years discussion around them would be long settled.

Legal under LBB2 '77. Implausible (there really ought to be some within-the-rules power system), but legal.

 

[robject]

The x-boat is TL10 which is in breach of the HG drive TL paradigm and is therefore only legal under LBB2 - which raises the question yet again of how you can have letter drives and % drives with contradictory TL paradigms in the same universe...

Traders and Gunboats, p46, corroborates Mike's statement.

TYPE X EXPRESS BOAT
X-51216 Express Boat X-1540041-000000-00000-0 MCr70.65 100 tons Book 2 Design Crew=l .TL=10. Passengers=l (possible). Low=O. Fuel=40. Cargo=l (possible). EP=O. Agility=O.

This works because they're using Book 2 jump drives.

But they're using computer rules from HG2, which is fine... unless the Model/4 is TL 13...

 

[mike wightman]

Model 4 is TL10.

 

[robject]

Model 4 is TL10.

Yah. I just looked it up and almost immediately after that, I saw your post here.

The High Guard jump-4 drives are TL 13.

However, perhaps silly-ly, the Book 2 jump-4 drives are TL 10.

It's almost perverse that you can use Book 2 drives to get around a TL limitation.

UNLESS...... well it makes me revisit the whole jump drive paradigm.

GIVEN, we KNOW that JUMP 4 IS A TL 13 THING. It was discovered at TL 13. It was NOT discovered at TL 10.

THEREFORE, it seems, somehow, that working J4 drives can be manufactured at TL 10, within "TL 13 space".

 

[Spinward Flow]

UNLESS...... well it makes me revisit the whole jump drive paradigm.

GIVEN, we KNOW that JUMP 4 IS A TL 13 THING. It was discovered at TL 13. It was NOT discovered at TL 10.

THEREFORE, it seems, somehow, that working J4 drives can be manufactured at TL 10, within "TL 13 space".

Ah, I see where you're going with that.

You have to make the breakthrough at high tech levels in order to enable the performance to be backported into lower tech level standard drive systems. Jump-4 needs to be "discovered" at TL=13 before previous tech levels can become "capable" of that performance output as a matter of engineering/control. So the LBB5.80 limits on jump per TL are still true, and once those breakthroughs are understood then lower tech level standard drives are capable of reaching up to that (new) performance limit.

So a TL=10 Jump-F drive is capable of up to Jump-6 performance in a 200 ton hull, but only after that Jump-6 performance is "unlocked" by a TL=15 advancement. If a society has only reached a maximum TL=13 then that same Jump-F drive in a 200 ton hull would be limited to only Jump-4 because the "fundamentals" of Jump-5 and 6 have not been "unlocked" yet by TL=14-15 advancements.

That's a reasonably clever bit of workaround that does not invalidate anything especially hard. It simply means that until the jump and maneuver drive numbers are "unlocked" as per the LBB5.80 table on tech levels, the standard drives are limited to those performance maximums. But then once those "unlocks" are achieved by the society and/or by technology transfer (knowledge has a way of crossing borders) then "older" standard drives can be "retuned" to deliver uprated performance courtesy of developments made elsewhere in custom (meaning prototype) starship designs that can then be rolled out more widely to the entire fleet inventory.



I approve.