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

[Grav_Moped]

Agent of the Imperium, which let's face it is a setting bible, has Imperial ships with jump 5 in the 400s, while jump 6 ships are mentioned in the 700s.

Building a semi-civilian xboat network to jump 4 standards when it could have been built to jump 5 shows the IN is not completely stupid.

I can live with that. Still seems odd they never mentioned anywhere that it became a HG design (because for them, it hadn't -- it was just grandfathered in), but that's on them.


One other implication of this is to break the whole genre of ships built as "add 100Td to a surplus XBoat to make something useful that does J2". They'd work if the XBoat has a Size B Jump Drive, but not with a J4 HG drive. (A HG drive that does J4 in 100Td does J2 for up to 166Td.) Yeah, they're broken anyhow since adding an M-Drive breaks the "engine bay size can't be changed after construction" rule, but still...

 

[Grav_Moped]

I have no idea what they intended, nor do I care to speculate.

I do, because it matters in how the rules should be interpreted. Or, as you might put it, it affects how one makes house rules.

 

[AnotherDilbert]

Agent of the Imperium, which let's face it is a setting bible, has Imperial ships with jump 5 in the 400s, while jump 6 ships are mentioned in the 700s.

I haven't read AotI, but from what little I have heard it seems to shake things up quite a bit...

Are those potentially prototype ships, or standard ships?

If they are standard ships the setting seems to have become distanced from even T5 rules.

It they are prototype ships, the eleventh century should see prototype Hop drives...

Building a semi-civilian xboat network to jump 4 standards when it could have been built to jump 5 shows the IN is not completely stupid.

That would say something about the IISS. Who knows what the IN is up to, apart from local J-6 fleet couriers?

 

[AnotherDilbert]

Because when you're two hours out from Jump Limit and some pirate decides that they deserve the MCr20 of computers you're hauling more than you do, that Cr10,417/month is going to be the best investment you made.

Any reasonable pirate will take you anyway and thank you for the extra value of the prize.

If you want to scare off pirates weapons are better and more cost-effective. A fusion gun should scare anything of 400 Dt or less.


Note: MCr 5 × 90% / 240 = Cr 18 750 per month higher mortgage over a m/1bis.

 

[AnotherDilbert]

Take the "diameter" of a 1KTd XBoat Tender as its length of 130m(?)*. 100 x 130m is 13000m.

It's supposed to be 1 kDt, not 10 kDt. Max dimension is 60 m according to S7.

At 1G, it takes about 36 seconds for an XBoat Tender to get 13000m (its 100D limit) away from its starting point.

D = at²/2 ⇒ t = √(2D/a) ≈ 51 s.


Sorry, couldn't help myself. It does not matter in the least for your argument, obviously.

 

[mike wightman]

I can live with that. Still seems odd they never mentioned anywhere that it became a HG design (because for them, it hadn't -- it was just grandfathered in), but that's on them.

The folks at GDW didn't use the rules as written for the OTU and that includes HG both editions and TCS.
The setting has TL10 jump 4 xboats that do not have a power plant or maneuver drive.

If you look at HG and compare with LBB2 there is one other glaring difference - they get the mdrive and jdrive sizes the wrong way round.

The vast majority of the CT OTU setting material uses LBB2 and pays lip service to HG - see The Traveller Advanture

One other implication of this is to break the whole genre of ships built as "add 100Td to a surplus XBoat to make something useful that does J2". They'd work if the XBoat has a Size B Jump Drive, but not with a J4 HG drive. (A HG drive that does J4 in 100Td does J2 for up to 166Td.) Yeah, they're broken anyhow since adding an M-Drive breaks the "engine bay size can't be changed after construction" rule, but still...

As I have said in many a thread over the years including earlier in this one - the HG design system is a totally different paradigm to the LBB2 system, they superficially appear similar but are actually very different.

 

[mike wightman]

I haven't read AotI, but from what little I have heard it seems to shake things up quite a bit...

You should, it will change a lot of the conceptions you have about the OTU - it did for me.
T5 is pretty much the game of the book, but guess what, there are subtle differences between the book setting and the T5 rules

Are those potentially prototype ships, or standard ships?

Standard, the jump 5 example is one of a fleet built for the IISS, while the jump 6 is a standard naval courier.

If they are standard ships the setting seems to have become distanced from even T5 rules.

No, it just means that what the military can build is usually in advance of the standard civilian TL - and that potentially the TL dates we have from MT days are the civilian rather than military dates.

It they are prototype ships, the eleventh century should see prototype Hop drives...

No. Remember a genius level breakthrough is required to discover FTL travel.

A culture could reach TL22 and never invent the jump drive but somehow achieve the breakthrough for hop drives, or never discover FTL at all. The Imperium and its successors may never discover the hop drive and then several centuries down the line make the breakthough for skip drives or what not.

Pre-grandfather no species in this galaxy had discovered the secrets of jump drive - this is a setting fact until MWM changes his mind

 

[BRover]

Under the rules, it's diameter, not mass. Take the "diameter" of a 1KTd XBoat Tender as its length of 130m(?)*. 100 x 130m is 13000m. At 1G, it takes about 36 seconds for an XBoat Tender to get 13000m (its 100D limit) away from its starting point.


*eyeballing it from deckplans that may not be accurate here...

True--but add the requisite handwavium, and it sounds OK.

 

[warwizard]

T4 rules are still OTU so can we consider FF&S rules as well in this discussion?

In that rule set we can design robotic drop tank tugs with a small HePLAR thruster and a 1m3 power plant to kick the tank out past the range of the jump bubble that normally destroys the drop tanks. The tug grapnels the tank, remaining attached while the jumping vessel is pumping for jump, then once the tank is jettisoned, the tug accelerates the empty tank, the tug has neither plumbing or electrical connections to the tank so the grapnel is minimum sized. Of course you will have a non zero chance that something will happen and the tank and tug are both destroyed, the thing is economic as long as the cost of tank + tug times chance of destruction is less than cost of tank that is guaranteed to be destroyed.

 

[AnotherDilbert]

You should, it will change a lot of the conceptions you have about the OTU - it did for me.

Despite appearances I don't care all that much about the OTU. MTU is more based on CT and perhaps a little MT.

In general I would separate the OTU per edition and not let later sources define earlier editions. E.g. I would not let AotI define the CT Imperium. I have taken some care in this thread to only use CT sources.

T5 is pretty much the game of the book, but guess what, there are subtle differences between the book setting and the T5 rules

I don't see any problem letting the setting introduce additional limitations, or small differences. That's basically what they are for...

Standard, the jump 5 example is one of a fleet built for the IISS, while the jump 6 is a standard naval courier.

No, it just means that what the military can build is usually in advance of the standard civilian TL - and that potentially the TL dates we have from MT days are the civilian rather than military dates.

Fair enough, it can be reconciled with that military TL was ahead of civilian TL before, but in 1105 they are both about TL-15, or perhaps jump tech was ahead of general TL.

No. Remember a genius level breakthrough is required to discover FTL travel.

Fair enough, that is certainly up to the setting to define.

... this is a setting fact until MWM changes his mind

Yes, that tends to keep track of the OTU interesting... Especially as most editions have no specific Imperial setting book.

 

[whartung]

It's supposed to be 1 kDt, not 10 kDt. Max dimension is 60 m according to S7.

D = at²/2 ⇒ t = √(2D/a) ≈ 51 s.

Sorry, couldn't help myself. It does not matter in the least for your argument, obviously.

A 100Kdton sphere is 300m in diameter. So, 30Km is 100D limit.

That's roughly 78s to get to 100D.

And, 100D should be the safe limit, right?

The question is whether the ship can wait the 1-2m after final fuel before "jumping". And, if not, what could be done to buffer that.

For example, there could be some tankage on the ship that's used to fuel the last 1-2m of the jump sequence, while the fuel shuttle gets away.

 

[Grav_Moped]

Any reasonable pirate will take you anyway and thank you for the extra value of the prize.

If you want to scare off pirates weapons are better and more cost-effective. A fusion gun should scare anything of 400 Dt or less.


Note: MCr 5 × 90% / 240 = Cr 18 750 per month higher mortgage over a m/1bis.

You can get a fusion gun in LBB2? Think bigger: particle accelerator barbette. Scares anything without armor.

Also, if you're going to spend another couple of MCr, install that second turret while you're at it. Computer gives bonuses to that too.

In terms of defensive capability, LBB2 simply doesn't provide much. No armor, no agility, just sandcasters, and lasers in the antimissile role -- and the Evade and ECM programs.

Adding acceleration capability if you're already at Pn=Jn is a huge hit to cargo capacity and your wallet.

Computer upgrades in LBB2 may be expensive, but they're one of the few defensive upgrade options available. And not a bad one at that.

 

[Grav_Moped]

A 100Kdton sphere is 300m in diameter. So, 30Km is 100D limit.

That's roughly 78s to get to 100D.

And, 100D should be the safe limit, right?

The question is whether the ship can wait the 1-2m after final fuel before "jumping". And, if not, what could be done to buffer that.

For example, there could be some tankage on the ship that's used to fuel the last 1-2m of the jump sequence, while the fuel shuttle gets away.

1-2 minutes is 10% of the 10-20 minutes a Jump burn takes. So, 10% of the total, or 1% MJn. It's there... but for a HG ship, that's all of the 4 weeks powerplant fuel.

 

[Grav_Moped]

The folks at GDW didn't use the rules as written for the OTU and that includes HG both editions and TCS.
The setting has TL10 jump 4 xboats that do not have a power plant or maneuver drive.

If you look at HG and compare with LBB2 there is one other glaring difference - they get the mdrive and jdrive sizes the wrong way round.

They didn't get them "the wrong way round" -- it's the right way round for HG's abstract combat system. It's only "wrong" if you're optimizing for LBB2 space combat or trying to RPG on a low level in a game universe that mostly fits the first three LBBs. (If the PCs are the command officers on a Lightning-Class Cruiser, well... ok.)

The vast majority of the CT OTU setting material uses LBB2 and pays lip service to HG - see The Traveller Advanture

Makes sense. They didn't want to obsolete one of the three core rulebooks or make LBB5 mandatory. In published scenarios, LBB5 ships are basically meant as setting chrome/wallpaper from the PCs perspective: they're things to avoid or outwit, or as the set for a scenario (AHL). In none of those cases does the size of each component in the drive room make much difference as long as it's close enough to maintain suspension of disbelief.

As I have said in many a thread over the years including earlier in this one - the HG design system is a totally different paradigm to the LBB2 system, they superficially appear similar but are actually very different.

Exactly. LBB2 is for the RPG aspect of the game, in which increased Jump capability is a PC goal and therefore expensive and a severe constraint to ship design but available if the PCs have the MCr for it. In LBB2 combat, maneuver (agility) isn't nearly as critical as it is in HG.

HG is for battles between large fleets and/or large ships in an abstracted system in which acceleration/agility rating is very important. Access to high Jn is limited by TL, and in the OTU that largely means access to Imperial technology.

 

[Grav_Moped]

...
The question is whether the ship can wait the 1-2m after final fuel before "jumping". And, if not, what could be done to buffer that.

For example, there could be some tankage on the ship that's used to fuel the last 1-2m of the jump sequence, while the fuel shuttle gets away.

True--but add the requisite handwavium, and it sounds OK.

Yep. As whartung pointed out, it might require a 1%/Jn buffer tank for the minute or two of Jump Fuel burn between disconnection and Jump. Or, maybe that's what the Jump Capacitors are for. Either way, not a big deal in the larger scheme of things.

 

[Grav_Moped]

I do, because it matters in how the rules should be interpreted. Or, as you might put it, it affects how one makes house rules.

To expand on that a little bit:

If the XBoat was grandfathered in reluctantly as a LBB2 design because it was integral to the setting, maybe there's nothing to be deduced from that.

If it was grandfathered in as a LBB2 design that uses the XBoat Tender as a drop tank, then tenders/tankers as drop tanks might be used in other circumstances.

If it was not grandfathered in but instead recreated in HG'80, it suggests that J4 is TL-13 and implies that the LBB2 drive ratings are capped by TL and drive size. (The Jump-3 Type T Patrol Cruiser is TL-10 in LBB2 -- was the Gazelle intended to supercede it?*)

If it was grandfathered in as an LBB2 design to support the idea that the first ship you get when you achieve the TL to build it in LBB2 is an XBoat analog (J3 at TL-9, 4 at 10**, 5 at 11 in 200Td, 6 at 12 in 400Td), then those LBB2 "_Boats" at those TLs should be legal somehow (or are at least an acceptable house-rule). And then you can take whatever rule interpretation you used to make it work under LBB2'81 and apply it elsewhere.

Conversely, the '81 rules eliminate useful (that is, with room for cargo, weapons, or carried fighters) Jump-5 ships before TL-12 and Jump-6 ones before TL-14. This was probably the intended effect (but I'm speculating about this).

A reasonable split (that they didn't do) might have been to have PN=MD but no less than Pn 1. But then you start getting questions about powering lasers and computers, which leads to leaning on HG and then things get complicated.

That's why intent matters.




*... by serving as an object lesson: "Build a Patrol Cruiser under HG rules, and you can have this instead. We're not saying not to use LBB2 any more, just pointing out that LBB2 ships suck by comparison to HG ones."
**The TL-9 and -10 XBoats are identical except that at TL-9 the best computer available is a Model/3, so the TL-9 XBoat can't do Jump-4.

 

[AnotherDilbert]

A 100Kdton sphere is 300m in diameter. So, 30Km is 100D limit.

V = ⁴/₃πr³ = ⁴/₃π(300 m/2)³ ≈ 14 million m³ ≈ 1 MDton.

And, 100D should be the safe limit, right?

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

The question is whether the ship can wait the 1-2m after final fuel before "jumping". And, if not, what could be done to buffer that.

We don't know how long things really take.

When the jump drive is activated, a large store of fuel is fed through the ship power plant to create the energy necessary for the jump drive. In the in- terests of rapid energy generation, the power plant does not work at full effi- ciency, and some of the fuel is lost in carrying off fusion by-products, and in cooling the system. 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.

That is technically CT, even if at the very end, I believe.

As far as I can see the entire process takes less than a few minutes or so, or at least burning the fuel. Hoping to pause the process a few minutes here and there to rearrange the tanks seems optimistic.

 

[AnotherDilbert]

You can get a fusion gun in LBB2?

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.

Think bigger: particle accelerator barbette. Scares anything without armor.

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

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.

 

[AnotherDilbert]

1-2 minutes is 10% of the 10-20 minutes a Jump burn takes.

That is not defined.

JTAS#24 disagrees. In LBB2 combat a ship can jump at the start of the turn, before any attacks, hence the jump is probably faster than an entire turn.

 

[AnotherDilbert]

To expand on that a little bit:

If the XBoat was grandfathered in reluctantly as a LBB2 design ...

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.