Book2 designed Xboats

[tbeard1999]

Perhaps this was solved elsewhere...

If I understand this correctly, there is a discrepancy between the 1st edition Book2 design of the Xboat as it appears in Supplement7, and the design rules from later editions of Book2. The newer editions necessitated that starships include a jump drive AND a power plant; therefore, by Book2 fuel formulae, a 100-ton Xboat needed 80 tons of fuel. This left no room for the drives, bridge, Model/4, 2 staterooms, and 1 ton of cargo.
...
-Fox

Yup, you can't design a 100 ton jump-4 craft in CT. The problem is the defective formula that CT uses to calculate power plant tonnage -- 10 tons per power number. So a 100 ton ship with Jump-4 and Power-4 has to have 80 tons of fuel.

Here's the solution in my Commonwealth Campaign:

Fast Couriers

Since communications is limited to the speed of travel, the Commonwealth interstellar communications network relies on courier ships. There are three classes of courier ships. Most ordinary communication is handled by a large fleet of Type S Scout/Couriers (Book 2, p. 19), These ships are capable of Jump-2 and provide communications be-tween worlds up to 2 parsecs away.
The X-Boat network relies on 200 ton CF-3 class Jump-4 couriers to provide high speed (up to Jump 4) service between key worlds of the Commonwealth.

These ships are operated by the Survey Service and private companies. In many systems connected by the X-Boat route, the Survey Service subcontracts private contractors who operate their own CF-53 couriers. Survey Service CF-3’s are not named, but are assigned a service number starting with 001 and currently going through 526. There are 81 systems on the Com-monwealth X-Boat route. Ships traditionally depart on Mondays, Wednesdays and Fridays. Considering overhaul and maintenance requirements, this means that about 486 couriers are required. The Survey Service operates 253 couriers and private contractors operate 104 couriers.

As a result, much of the X-Boat fleet is behind on scheduled maintenance. Remarkably, there’s been no statistically significant increase in the accident rate. However, maintenance deferred usually costs more in the end, so the Survey Service is having to increase the X-Boat budget, at the cost of exploration and (particularly) interdiction. X-Boat costs are per jump, and run about cr10 per jump per terabyte of data or kilogram of weight. A courier typically carries triple redundant data storage facilities for 10 million terabytes of data. If this sounds impressive, consider that the typical TL11 high population world planetary data network carries about 1 billion terabytes of data per day. (Just made these numbers up, by the way).

Each courier can carry 9,000 kg of cargo. On non-Survey Service couriers, two passengers can be carried in lieu of the cargo for cr60,000 per passenger per jump. This is three times the going rate for Jump-4 high passages and there is usually a waiting list. The accommodations are cramped, with both passengers sharing a stateroom (or half the stateroom filled with mail if only one passenger is going) and eating in the crew galley. Also the passenger must arrange transport to and from the courier tenders. However, the difference is speed. Commercial Jump-4 liners average 8 parsecs per month; the X-Boat network averages about 14 parsecs per month.

CF-3 Fast Courier

Type: Courier
Displacement: 200 tons
Empty Cost: MCr 128
Drives: Jump D, Maneuver A, Power D, giving Jump-4 and Maneuver-1
Computer: Model-4
Fuel: 120 tons
Staterooms: 2
Cargo: 9 tons
Armament: none (crew has small arms)
Crew: Pilot/Navigator; Engineer

 

[boomslang]

CF-3 Fast Courier

Type: Courier
Displacement: 200 tons
Empty Cost: MCr 128
Drives: Jump D, Maneuver A, Power D, giving Jump-4 and Maneuver-1
Computer: Model-4
Fuel: 120 tons
Staterooms: 2
Cargo: 9 tons
Armament: none (crew has small arms)
Crew: Pilot/Navigator; Engineer

Lookin' good, but two notes re: CT --

1. You need a Medic at 200 dtons and above, unless House Ruled (Aslan excepted).

:smirk:

2. You need a Gunner and installed ship's weaponry if you haul Mail, unless House Ruled. And since Mail is commercial service, the crew will all need single occupancy, again unless House Ruled.



It's why I settled on 195 dtons for my Type XC Express Courier; it cuts the crew roster in half...

:devil:

 

[tbeard1999]

Lookin' good, but two notes re: CT --

1. You need a Medic at 200 dtons and above, unless House Ruled (Aslan excepted).

:smirk:

2. You need a Gunner and installed ship's weaponry if you haul Mail, unless House Ruled. And since Mail is commercial service, the crew will all need single occupancy, again unless House Ruled.



It's why I settled on 195 dtons for my Type XC Express Courier; it cuts the crew roster in half...

:devil:

Yes, you're correct re medics and re staterooms for commercial vessels. I've always considered requirements for medics and suchlike to be Imperial regulations. Since my campaign is not set in the Imperium, I feel free to change them. That said, the Commonwealth has similar regulations to the Imperium on such matters. The difference is that military (and quasi-military) organizations can be exempt from such regulations. In the case of the Survey Service (the Commonwealth scout service), the Survey Service is exempt from legal minimums, since its under the command of the Prime Minister (separation of powers, you see). And Parliament has granted an exception to the normal rules for private contractors operating couriers in the X-Boat network. The alternative would be for Parliament to dramatically increase Survey Service funding, and high taxes are not politically feasible in the free market Commonwealth.

If your campaign is set in the Imperium, there are no private contractors operating X-Boats. And you can use similar rationales to exempt private contractors from the rule requiring single occupancy (it's obviously not a *real* limit, since military craft can do it). I have no problem assuming that the scouts are able to use the same occupancy rules as the Navy.

Re: gunners--I don't think that large companies working under direct contracts with the Survey Service (or Scout Service) as part of the X-Boat network would be subject to the same rules that would apply to regular mail ships (many of which are presumably operated by comparatively small companies or individuals). X-Boat couriers are single purpose ships; mail ships deliver mail *and* do a lot of other things. In any case, Parliament is easily able to make a business decision.

Besides, I'd rather ignore a few manning and legal requirements than ignore the starship creation system (like GDW had to do).

I use a nifty program to create my Book 2 designs, but one limit is that it cannot do non-standard hull sizes. Otherwise, your 195 (or 199) ton fix would work as well. And I could easily see the Survey Service designing its couriers to exploit legal loopholes on manning requirements. Especially if it intended to use private contractors to operate such ships.

 

[Foxroe]

I like the 200-ton idea, but it doesn't "feel" right for the OTU.

Another idea that I had tossed around was making Xboats only capable of jump-2. How bad would the impact be on communications and the timeline of Imperial history, I wonder? Eye-balling the maps, it looks like about 66% of the routes are jump-3 or jump-4, which should translate to an equivalent increase in communications time (my math may be off). Xboats would have maneuvering capability, so there would be no real need for tenders. Instead of tenders, empty hexes on the maps along the boat routes would have to have deep-space way stations. The alternative would be to double up on the jump fuel in the Xboats.

-Fox

 

[Foxroe]

On a related side note: I believe that MWM is quoted in print as defining the duration of a jump as 168 hours, +/- 10%. Is this variability random? Can it be modulated in some manner? For instance, if a Navigator plots a course to a system that he has never charted a jump to, would the duration be entirely random? But if said Navigator has jumped to that system many, many times, does the duration shorten to 151.2 hours for every jump that is made to that system? If this is true, would pre-charted jump routes purchased on cassettes provide this same temporal advantage (perhaps at a higher cost)?

Or maybe…

Due to gravitational relationships between certain systems, the jump routes between these systems result in slightly shorter transit times, while other inter-system jumps necessitate longer jump durations. This might explain why some of the Xboat routes take the path that they do – the Imperium wants communications to follow the fastest possible path. If this is the case, then a 100-ton Xboat could get away with 40 tons of fuel for a jump-4, and another 10 tons of fuel would provide power for the duration of the jump (151.2 hours) and then another 16.8 hours of power after arriving in system… those tenders would have to be real close.

-Fox

 

[tbeard1999]

I like the 200-ton idea, but it doesn't "feel" right for the OTU.

Another idea that I had tossed around was making Xboats only capable of jump-2. How bad would the impact be on communications and the timeline of Imperial history, I wonder? Eye-balling the maps, it looks like about 66% of the routes are jump-3 or jump-4, which should translate to an equivalent increase in communications time (my math may be off). Xboats would have maneuvering capability, so there would be no real need for tenders. Instead of tenders, empty hexes on the maps along the boat routes would have to have deep-space way stations. The alternative would be to double up on the jump fuel in the Xboats.

-Fox

Looks to me like a Jump-2 communications network (which is the standard communications network IMTU, supplemented by a Jump-4 network) would require the Imperium to be smaller. The speed of communications constrains the maximum size of an empire. If the Imperium is straining at its current size--implied by many Traveller supplements and adventures--with a Jump-4 network, then reducing that to a Jump-2 network would dramatically reduce the size that the Imperium could reasonably be. Let's assume that the reduction to jump-2 doubles communication time (it's true that not every link is a Jump-4 link, but there will be a lot more unbridgeable chasms with Jump-2 ships than Jump-4 ships, which will require less direct paths to the core). In that case, the Jump-2 Imperium would be 1/4 the area of the Jump-4 Imperium.

I think that Jump-4 communications are important enough that the Imperium would deploy 200 ton couriers if necessary. But it would be expensive; in my Commonwealth campaign, you'll note that the X-Boat network is not fully funded.

Just my random thoughts...

 

[tbeard1999]

As an aside, it seems to me that one major advantage of a well-funded dedicated X-boat system is that the message speed can be nearly doubled over commercial ships without increasing jump drive capacity.

Commercial ships average 2 jumps per month. So a message on a single Jump-2 courier would travel 4 parsecs per month.

But if a daisy chain type system were in place, this message could be handed off to a new ship at the end of each jump. Assuming a day to do this, the message could travel nearly twice as fast -- 6.66 parsecs per month -- with no increase in drive speed.

So a version of the X-Boat network built around Type S scout/couriers would still be pretty good.

 

[boomslang]

I like the 200-ton idea, but it doesn't "feel" right for the OTU.

Another idea that I had tossed around was making Xboats only capable of jump-2. How bad would the impact be on communications and the timeline of Imperial history, I wonder?

Horrific and nightmarish, I expect.



You'd need to make them Jump-2x2 to work the plotted routes, but the commo lag would make the system useless over long distances (as per tbeard1999 above).

BTW, you *can* do Jump-2x2 in 100 dtons; for example, if you take a Type S and gut all payload and accommodations (including weaponry) except for a single stateroom, it'll serve. But it's kind of a pointless exercise...

 

[boomslang]

On a related side note: I believe that MWM is quoted in print as defining the duration of a jump as 168 hours, +/- 10%.

Well, it was never-really-playtested article in the dead-tree JTAS, which makes it technically an "optional rule", at least within the CT canon. It is canonical in MT and all later versions of Trav.

But it never appears in any version of the LBBs or the BBB.

And it creates many more problems than it solves...

It's a bad idea. It only persists because so many Traveller refs are addicted to using random die rolls to passive-aggressively screw over their players, I suppose... remember: Trav is renowned as the only RPG in which your PC can actually die during the process of character creation... which kinda sets an abusive precedent right out of the gate, there.

Is this variability random?

Not just "yes", but "Hell, yes!"

Can it be modulated in some manner?

Not just "no", but "Hell, no!"

The best you can do is that a good Navi can plot an exit point within, oh, I dunno, 2 days' travel time of the destination. A bad (or lack of any) Navi can drop your arse out of Jumpspace the better part of a week from the starport.

Good luck making your bank payments that month, chumps...

:smirk:

And don't start me on the mess it makes of naval fleet operations and the wildly-loopholish handwaves that get proposed as a result...

:nonono:

 

[boomslang]

Commercial ships average 2 jumps per month.

See, not at 168 hours ± 10% they don't. By the time you add up all the in-system travel and passing through customs, if you want to spend a full week in port to get the good cargo/passenger rolls, you'll be lucky to work in two jumps in less than 30 days. 32 to 33 days ends up being typical.

Which is more than four weeks... and means you're down to at best 23 jumps per year, not 25...

Hmm... perhaps it's time to dust of the old "Repo Agent" character template...

 

[boomslang]

Yes, you're correct re medics and re staterooms for commercial vessels. I've always considered requirements for medics and suchlike to be Imperial regulations. Since my campaign is not set in the Imperium, I feel free to change them. That said, the Commonwealth has similar regulations to the Imperium on such matters. The difference is that military (and quasi-military) organizations can be exempt from such regulations. In the case of the Survey Service (the Commonwealth scout service), the Survey Service is exempt from legal minimums, since its under the command of the Prime Minister (separation of powers, you see). And Parliament has granted an exception to the normal rules for private contractors operating couriers in the X-Boat network. The alternative would be for Parliament to dramatically increase Survey Service funding, and high taxes are not politically feasible in the free market Commonwealth.

Interesting.

IMTU, in the absence of any one over-arching interstellar government such as the 3I, Mail Service is what holds the various disparate societies and cultures of interstellar civilization together. In some polities, Mail delivery is a government service, in others it is a commercial enterprise, and in areas without interstellar governments at all it is a very dangerous and exciting activity...

 

[aramis]

See, not at 168 hours ± 10% they don't. By the time you add up all the in-system travel and passing through customs, if you want to spend a full week in port to get the good cargo/passenger rolls, you'll be lucky to work in two jumps in less than 30 days. 32 to 33 days ends up being typical.

Which is more than four weeks... and means you're down to at best 23 jumps per year, not 25...

Hmm... perhaps it's time to dust of the old "Repo Agent" character template...

It's only 7 hours each way (size A, 1G Drive), plus 5 dirtside...
168 hours is 7 days exactly, plus 17h is 7.708d , plus another .3 to land...

So yes, it can be done regularly.

For a routine land, fuel, and take off, assuming 5 hours to fuel, call it a 9 day cycle. 3 jumps per 28d Imperial month. With a day to spare.

 

[boomslang]

For a routine land, fuel, and take off, assuming 5 hours to fuel, call it a 9 day cycle. 3 jumps per 28d Imperial month. With a day to spare.

Ah, but you see, canon also informs us (in one of the early paragraphs introducing "Interstellar Travel") that non-commercial vessels may refuel and depart immediately, averaging one jump per (presumably 7-day) week.

(For that matter, TCS lets you fight an entire space battle between Jumps, and still refuel and stick to the one-completed-Jump-per-week schedule on a long-term, strategic scale.)

Allowing for the suggested and conservative 9-day cycle you estimate, 168 hours ± 10% breaks CT canon.

Q.E.D.

No, really. I know lotsa folks are totally married to it, but it ain't in there to begin with and it won't fit no matter how much you try to retcon it...

I think a more reasonable number for Marc to have pulled out of hard vacuum would've been 150 hours ± 10%; that would've provided the desired (if incompatible with any theoretical model of interstellar Navigation) randomness, while still preserving the "one Jump per week" rule of thumb and allowing a modest in-system operating margin for refueling and so on. (18 hours ± 15 hours.) Under such a formula, the worst-case scenario would be a 165-hour Jump, which still leaves three hours to hustle and try to get back on schedule the <3% of the time it happens.

But Marc didn't ask me at the time, and avoids the subject on those rare occasions when I do mention it to him in passing, so it's beating a dead poni, I suppose.

I have other reasons for preferring a fixed Jump duration, but they're already posted on these boards elsewhere, IIRC... accurate timekeeping for cartographers and Jumping within the Milky Way's 10-diameter limit and stuff like that...

 

[tbeard1999]

"Commercial starships usually make two jumps per month. They spend one week in jump, followed by one week in the star system, travelling from the jump point to the local world, refuelling, marketing cargo, finding passengers, leaving the starport and proceeding to a jump point again. ...

"Non-commercial ships usually follow the same schedule of one week in jump and one week in a system. If haste is called for, a ship may refuel at a gas giant immediately, and re-jump right away. This allows the ship to make one jump per week, but makes no provision for cargo, passengers, or local stops."

Book 2, 1981 Printing, p. 4

 

[robject]

"Non-commercial ships usually follow the same schedule of one week in jump and one week in a system. If haste is called for, a ship may refuel at a gas giant immediately, and re-jump right away. This allows the ship to make one jump per week, [...]

...more or less.

Close enough for government work.

Hmmm, does sound like a bureaucratic SNAFU. "First, assume a spherical horse..." Cynical! The more I think about it the more I like it.

 

[boomslang]

...more or less.

Close enough for government work.

Um, that's kinda the point: it ain't. ObThisThread: the Xboat system begins to fall apart if it can't stick to a regular schedule -- the tenders don't know when to be where for Breakouts, that becomes a real problem with Pilots routinely coming out of Jump relying on vacc suit life supp & Fast Drug to save their lives, then it's impossible to schedule the logistical support at Way Stations because the Boss Dusters have no way to model the movement of the assets spread across the network, and so on and so on...

How you know Marc pulled that number out of hard vacuum when put on the spot by gearheads at a convention panel: if it had actually been playtested, it would at least reflect the basic CT mathematics and be "161+2d6 hours"... there is simply no way in the basic CT game mechanics to do a normal probability distribution over "±10%" with six-sided dice...

:smirk:

 

[far-trader]

Just FWIW (and to answer the earlier question later) I've never pegged the "random" time and space (off target by 3000km per parsec?) effects of jump travel as anything but a metagame function.

In the game (imtu at least and supported by examples in the otu) the exact time and place of jump travel is a known factor to a high degree of certainty, before the jump is made, as long as everything is operating properly.

Sure if...

...your drives are out of spec for lack of maintenance,

...you're cheaping out on fuel,

...you try to jump from within(1) a gravity well,

...you miss the outbound jump window's precise X:Y:Z/time that you plotted for the jump to start from(2),

Then there's gonna be unknowns thrown into the equations that can be inconvenient if not downright lethal. But that's supposed to be the exception, not the rule.

So, I roll the dice and tell the Navigator that the best jump plot will get them from a precise X:Y:Z/time coordinate of their choosing to the desired place (as close as possible - random rolls for time and distance) at precisely X:Y:Z/time coordinate with orientation as desired.

(1) or into a gravity well, a little twist imtu, similar effects for misjumps based on origin within 10d or 100d, but applied at the destination end

(2) such as from a jump plot on a self erasing cartridge or one calculated in advance and used in emergency before or after the correct time or at another X:Y:Z coordinate

 

[aramis]

there is simply no way in the basic CT game mechanics to do a normal probability distribution over "±10%" with six-sided dice...

:smirk:

Wrong. (2d-7)*2%....

2d6:
2 151.2 hours
3 154.56 hours
4 157.92 hours
5 161.28 hours
6 164.64 hours
7 168 hours
8 171.36 hours
9 174.72 hours
10 178.08 hours
11 181.44 hours
12 184.8 hours

 

[boomslang]

Wrong. (2d-7)*2%

Hmmm... perhaps so... if you use Swatch Time or something equally-contrived that counts hours to two decimal places -- and doesn't round off to the whole number like CT does for everything.

But that still doesn't make it canon...

:nonono:

 

[aramis]

But being in MT, TNE, and T4 does makes 168:00±16:48 canon for the OTU, whether or not it's canon for non-OTU CT campaigns.

THat the dicing only comes close to it is fine by me; an abstraction for game purposes.