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CT 2 x J6 ship

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I use CT ship design, with some additions allowed from HG.

A long time ago, there was much discussion over drop tanks (External demountable fuel tanks) in the TML and in the various usenet discussion groups.

I have come up with the following - it may not work IYTU!

The Type ZZC Special Experimental Courier (with external fuel tanks)
Constructed at TL15, and based upon a Dispersed Structure shaped 2,000-ton Unstreamlined hull, the Type ZZ mounts Jump Drive Z, Manoeuvre Drive K and Power Plant Z, giving a performance of Jump-6 and 1G Acceleration. Fuel tankage of 28 tons supports the power plant for 14 days, Adjacent to the Bridge is a Model/6 Computer. 4 hardpoints are fitted as standard. No turrets are mounted. No weapons are mounted. 4 tons are allocated for gunnery control. Accommodation comprises 4 Standard Staterooms and 4 Half Staterooms. There is no cargo capacity. 480-ton space allocated for second fuel tank. 1200-ton space allocated for collapsible fuel tanks.
The Type ZZC Special Experimental Courier (with external fuel tanks) costs MCr744.000 (MCr669.600 with standard discount)

Crew is 12 (Pilot, Navigator, Sensor Ops/Comms, 6 Engineers, Maintenance Technician, Medic & Commander)

The 1200t external fuel tanks allow for 1 jump-6.
Then they are jettisoned, leaving an 800 ton ship, with a 480t internal fuel tank - enough for a second jump-6.

This assumes that a Jump Drive Z can be 'tuned down' to act as a Jump Drive W (thus allowing an 800t ship to make a jump-6)

I would envisage the time taken between jumps to be about 12 hours to demount the tanks, retune the Jump Drive and recharge the Jump Grid. There is not enough space (actually, there is NO space) in the 800t craft to stow the demounted tanks. Using just HG rules, it might be possible to design a ship that could.

This ship would ONLY be of any use as a super-fast courier, or Rift crossing courier. As it MUST end it's second jump in a system where it can be refulled in orbit (non-streamlined, remember) it can average a little over J11 per fortnight.

From Capital to Mora, the Type TJs can do nearly J6 per fortnight, and from Terra to Mora (going around the rift) the average is only J3.4 per fortnight, so the ZZC is nearly three times faster.

(BTW, it is commercially completely unviable ...)

Any thoughts, comments or flames?
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Only enough power for the power plant for 14 days? They can jump but remember jump can take 6-8 days. Get two 8 day jumps and life support failed 2 days before you arrive. Everyones dead. This doesn't include time taken to get from planet to jump point and back.

Anyway 2000 tons seems a bit large for a simple courier.
 
Yes, I realise the 14 days problem (I thought about that after posting) so it relies upon some exceptional navigation to make sure that you end up <1 day from your pickup ship

If necessary the crew could be cut by2, giving you an extra 4t = 2 days of life support

2000t is indeed far too large for a courier - even if you say it's 800t with 1200t of extra fuel, that's too damn big and expensive for any but highly important 'speed-is-critical' missions

But hey, in a war situation, there might be enough of those missions to make it viable to have a couple of these on standby in vital positions?

Image if one were stationed at Mora in 1107.

The news of the Zhodani attack can now be gotten back to the Corridor fleet in 2 weeks rather than 4, and to Capital in 8 weeks rather than 15.

How much difference would the arrival of the Corridor fleet have made 2 weeks into the Zhoi attack?
 
Hi Ghunkugoe, since you asked I'll toss in my cr.02 but as always what ever is right for your game is right.

First off, the idea of a special J6 courier is certainly merited, and 2000 dT is not unreasonable, since there is actually a canon published design that is exactly this. Suprised?



Spoiler Warning? Just in case there is a player here who actually wants to maintain some genuine lack of knowledge and wonder. Scroll down if this is not applicable...
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Just a little more, you have been warned, how I wish I could forget more of what I know and be a fresh newbie player again <sigh>...
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OK :D

Its from MegaTraveller:

"The Imperiallines TI Frontier Transport is a common sight throughout the Imperium, operating on trade and commerce missions to worlds off the main trade routes."

That is the description for the commonly known and encountered version, a 2000 dT J2 2G hauler, no passengers. What is less widely known is that this ship is also a cover for a few special versions (type TJ) that sacrifice most of their volume for J6 performance. Externally the two versions are identical. These are used to, in secret, cover long distances with vital information and/or a couple special passengers, quicker than the public J4 X-boat.

So in your example of knowledge about the war, it is actually canon that said info reached those who needed to know on Capital quite some time before it did so on the X-boats and became public knowledge. As for why there wasn't a quicker response I could only guess planning and recall of elements, though perhaps a few chosen special forces might have been sent early.

Hmm, come to think of it now I might have missed doing a CT conversion of this ship for my own long lost game, have to track down the specifics and have some fun, thanks for the inspiration. Of course I'll have to do one for my new to be T20 game too. I really need to finish my time dilation field generator so I have time to do everything I want to get done :rolleyes:
 
I found the ship described in the MT Rebellion book and used my version of falkyn's excellent ship design Excel spreadsheet to create it in T20. The J6 version (notes: Avionics model type is my version to describe the maximum hull size, in this case 4000 [4T] tons), Nuke Dampers larger USP than given but smallest I could fit as T20 does not have optimum option, added a few spare staterooms for passengers and troops, removed the Fusion Gun and Missile Turrets as it isn't a true combatant and a civilian version might draw too much attention if it has too many weapons-and to get everything to fit
):


Frontier Transport

Statistics:
2,000 ton Hull (Close Structure) - Streamlined - USP: B
AC: 9 (6 vs. Meson Guns) AR: 0 SI: 275 Initiative: 0
Starship Size: Large Cost: 1,462.934 MCr (1,828.668 MCr without discount)
Computer: Model/7 Fib, Avionics: Model/4T
Sensors: System Wide, Communications: System Wide (Maser, Meson)
Cargo: 11.5 tons
Annual Maintenance = 146.2934 KCr (73.1467 KCr if maintained routinely)
Routine Maintenance = 45.7167 KCr/Month

Performance:
Jump-6 (enough fuel for 1 x Jump-6)
Acceleration: 2-G Agility: 0
Power Plant: TL-15 Fusion (176.0 EP output, duration: 4 weeks)
Total Fuel Tankage: 1,288 tons
Fuel Scoops, Fuel Purification Plant (TL-15, 5 hrs per 1,400 tons of fuel)
Atmospheric Speeds: NOE = 1,175kph Cruising = 3,525kph Maximum = 4,700kph

Active Defenses:
Nuclear Dampers - USP:4

Weapons:
Hardpoints: 6
3x Triple Beam Laser Turret TL-15, +4 To Hit, 4d8 (20/x1), Range: 30,000km
3x Triple Sandcaster Turret TL-15, +5 AC, Ammo: 60 sand canisters

Ship's Vehicles:
1x 5-ton vehicle hangar (air/raft)
1x 95-ton small craft (shuttle)
Launch facilities for 1 Craft per turn
Accomodations & Fittings:
Bridge
14x Single Occupancy Stateroom (14 People)
15x Double Occupancy Small Cabin (30 People)
6x Emergency Low Berth (24 People)
1x Sickbay (2 Patients)
4x Airlocks

Crew Details:
7x Command Officers, 3x Command Crew
1x Flight Officers, 1x Flight Crew
1x Gunnery Officers, 10x Gunnery Crew
2x Engineering Officers, 4x Engineering Crew
1x Medical Officers, 0x Medical Crew
4x Service Crew


The J2 version has 880 tons more cargo and requires 1 less Engineer, cost drops to 1207 MCr. It also has 2 Agility unless you want to shrink the power plant as well but it is probably cheaper to keep the same power plant for the mass production benefit. Reducing the PP: +80 tons cargo, Cost is 1111 MCr.


Oh yeah, not in the T20 format, but in the format falkyn put in the spreadsheet (which I like). Eventually one of us will probably put in the T20 design worksheet style in the spreadsheet (or is that copyrighted?).
 
Originally posted by far-trader:
First off, the idea of a special J6 courier is certainly merited, and 2000 dT is not unreasonable, since there is actually a canon published design that is exactly this.
The Fleet courier [FS:20] is only a 400 T design. It is impossible to get jump-6 in a 100 T hull and IIRC it is also impossible to get it in a 200 T design. I'm not sure about 300 T. Jump-5 should be possible with a 200 T hull.

2000 T is way too much for a simple courier (the design you mention is so big only because it has to look like another 2000 T design).


Hans
 
Originally posted by rancke:
It is impossible to get jump-6 in a 100 T hull

<snippage>

Depends I guess on if you allow drop tanks or not. I have a nice little 100 dT J6 6G racing yacht. Of course it relies on drop tanks for any but short routine jumps and is a bit pricey and totally impractical commercially, but man does it go!

2000 T is way too much for a simple courier (the design you mention is so big only because it has to look like another 2000 T design).


Hans
Quite true, it is a Q-ship and wouldn't need to be that big except for the blending in aspect. Mainly my point was there is a canon precedent for such a large ship being used in a clandestine express courier capacity. I'm not sure the Imperium would encourage open public access to J6, just so it could maintain a small edge over public information.
 
I know about the TJ (and mentioned it in the original post)
It can average almost J6 per fortnight (two weeks)

I had assumed that this is how the news of the Zho invasion DID get to the Corridor fleets in only 4 weeks (XBoats would take 6 weeks)

By allowing two J6 jumps per fortnight, this design would get the information there in little more than half the time.

I don't really want to restart the 'drop tank' argument, but my take is that the fuel is required throughout the jump, thus the volume of the tanks must be taken with you and dropped after arrival.

This design allows for one jump-6 with the tanks, and another, almost immediately, without them.
 
Originally posted by Ghunkugoe:
I know about the TJ (and mentioned it in the original post)
Right you are, missed or blanked it, my goof. "Read twice, post once." ;)


I don't really want to restart the 'drop tank' argument, but my take is that the fuel is required throughout the jump, thus the volume of the tanks must be taken with you and dropped after arrival.

This design allows for one jump-6 with the tanks, and another, almost immediately, without them.
I did see that, and like it. Nuff said about the "drop tank" issue. The key would be figuring out where to station these ships and what to do with them between need (if anything), if the primary design reason is vital info in half the time. Included in this factoring would be refuel points at the ships extreme range, say 9-12 parsecs per leg depending on the route and astrography. These could have fully fueled and purified external tanks ready at secret locations with a small base to keep watch and top up the internal tankage.

One more issue. The ship has 4 tons allocated for fire control but no weaps mentioned and no gunners included in the crew. Given the nature of its mission and the tight power supply duration maybe you could consider replacing some or all of the weapon reserve volume with fuel and/or emergency low berth(s) for some of the crew. Just a thought. Or did I miss something again?
 
Originally posted by Ghunkugoe:
I know about the TJ (and mentioned it in the original post) It can average almost J6 per fortnight (two weeks)

I had assumed that this is how the news of the Zho invasion DID get to the Corridor fleets in only 4 weeks (XBoats would take 6 weeks)
I assume it got their by Fleet Courier. The Imperial Navy has jump-6 couriers [FS:20]. (Just how much use the Imperial Family actually gets out of its secret courier network is unclear to me.)


By allowing two J6 jumps per fortnight, this design would get the information there in little more than half the time.
A single courier should be able to average one jump per 8 days (less if it doesn't have to refuel from a gas giant. A large number of couriers set up pony express style can average a few hours less than 7 days*.


Hans

* Yes, I do mean less than 7 days. You send off a number of couriers with the same message. The average time for at least one of them to reach the destination is less than 168 hours. You have a second groop of couriers ready to jump as soon as the first courier arrives at its destination and the message is transmitted to them. The first courier group won't be ready to jump again until the last of the group to arrive is ready, so this method is even more expensive than multiplying by the number of couriers. (An added benefit is that even if one courier misjumps, the other(s) will get the message through).


IMTU I calculate jump duration as 140+8d6 hours (I can't recall if this is from an official source (GT?) or something I made up myself). With this two couriers average 165.3 hours, 3 couriers average 163.9 hours, and 4 couriers average 163 hours. Beyond that the gain in efficiency is minimal (8 couriers average 161.1 hours). I have my IN use pairs of couriers for routine messages and more for priority messages. YMMV.
 
Darn...I could almost smell smoke and flames after reading these post...smelled GREAT!!!...any way here goes. My favorite ship is the old Gazelle class (I love it for some reason). those drop tanks are neat....and i DO NOT belive design Engineers would drop the CONCEPT of DROP TANKs, i belive they would be used and changed Thruout Imperial History, the idea and concept of Droptanks is just to useful, you can change, modify, them for dran near anything!!!
 
This thread is pretty good, but don't forget the COLLAPSABLE fuel tanks!

The ones that fit in your cargo hold and are filled up only when you need them. They take up a little cargo space (even more when they are filled
) but they don't run the risk of being shot off by the first enemy battery.
 
But collapsble tanks are pretty worthless for dedicated long-range ships like couriers, since they don't give you any more fuel capacity than a standard built-in tank would.
 
Just did some doodling to see how small a J6 x 2 courier can be in T20. Turns out 500 tons is probably real close to the lower limit, assuming you use the fuel consumption implied on p.354.

Springer Class Courier (TL 15)
Designed by: Tom Schoene

Statistics:
500-ton Hull (Flattened Sphere) - Streamlined
AC: 12 (10 vs. Meson Guns)
AR: 0
SI: 160
Initiative: 2
Starship Size: Medium
Cost: 239.259 MCr (299.074 MCr without discount)
Model/6 Computer
Avionics: Less than 600-ton
Sensors: Medium Range
Communications: Extreme Range
Cargo: 4.-tons
Extra Ship's Stores: 24 person/weeks of Standard Stores,
Annual Maintenance = 23.926 KCr (11.963 KCr if routinely maintained)
Routine Maintenance = 5.981 KCr/Month (59.815 KCr per year)

Performance:
Jump-6 (enough fuel for 1.2x Jump-6)
Acceleration: 2-G Agility: 2
Power Plant: TL-15 Fusion (35 EP output, enough fuel for 2.99 weeks)
Atmospheric Speeds:
NOE = 1,175kph
Cruising = 3,525kph
Maximum = 4,700kph

Active Defenses:
none

Weapons:
Hardpoints: 3
2x Triple Beam Laser Turret TL-15, +4 To Hit, 4d8 (20/x1), Range: 30,000km
1x Triple Sandcaster Turret TL-15, +5 AC, Ammo: 20 sand canisters

Ship's Vehicles:
none

Accomodations & Fittings:
4x Double Occupancy Stateroom (8 People)
2x Emergency Low Berth (8 People)
1x Airlock

Crew Details:
1x Pilot
1x Astrogator
2x Engineer
3x Gunner

Description:
The Springer is a fast courier designed to carry extremely important messages and sometimes very small high-priority cargos as quickly as possible. One passenger can be carried (more if they can replace the ship's gunners), but no ammenities are provided. In rare circumstances, more passengers could be carried in the ship's emergency low berths, thought there is significant risk involved. (The low berths are installed primarily to give the crew a chance of survival in a misjump.) The ship has limited armament, sufficient to deter "casual" pirates but not a committed attack. Therefore, the Springer is generally used only in secure areas where the risk of attack is low.

This design uses a 240-ton drop tank, which costs MCr 0.25. This tank would generally be discarded before jump, allowing the ship to make two successive J-6 jumps without refuelling. (The 60 tons of fuel required to maintain the jump field during the first jump are stored internally, along with the 300 tons of fuel required for the second jump.) There are caches of tanks and refuelling facilities located along the primary courier routes, allowing these ships to pick up replacement tanks as needed.
 
Originally posted by trader jim:
...I DO NOT belive design Engineers would drop the CONCEPT of DROP TANKs, i belive they would be used and changed Thruout Imperial History, the idea and concept of Droptanks is just to useful, you can change, modify, them for damn near anything!!!
It's not a matter of choice. I'm sure starship engineers have been fantasizing about drop tanks for millenia, but the crucial invention that made them possible wasn't made until the last half of the 11th Century. That's just a historical fact. In the OTU, that is. Doesn't say anything about how things are IYTU.

Just keep in mind that drop tanks change the economics of starship travel drastically. If you don't restrict them some way (like, for instance, say that they are a fairly recent invention and hasn't had time to change the market yet), you will more or less eliminate non-drop tank ships between medium- and large-sized starports. And if you have jump-5 or jump-6, long-distance freight and travel becomes much cheaper.


Hans
 
Originally posted by Tom Schoene:
But collapsble tanks are pretty worthless for dedicated long-range ships like couriers, since they don't give you any more fuel capacity than a standard built-in tank would.
No, it's mostly for free traders (the career, not the ship) who want an inexpensive alternative to doubling the jump ranges of their merchant ships between fuelings. You only fill them when you need to jump those extra parsecs.
 
I like the idea posted here
http://www.travellerrpg.com/cgi-bin/Trav/CotI/Discuss/ultimatebb.cgi?ubb=get_topic;f=4;t=000266 by far trader - Drop Tanks ARE available, but Imperial regulations forbid them for any passenger craft, and 'standard' employment contracts demand premiums for crews manning craft with them.

And in answer to a previous question, I left the armament off the ship to allow customisation (IMTU players never know for sure until they find out the hard way exactly what weapons have been fitted to any ship)
The Maintenance Tech, Sensor Ops and Medic would all double up as gunners, with one turret filled with lasers set to anti-missile and run by the computer - but again, there is room here for variety.

I've been reading about the 80/20 rule, but I prefer the idea that more of the fuel is needed throughout the jump. My TU handwavy technology says that the fuel is used to power the jump grid of the WHOLE ship (including drop tanks) and to 'rip open' the window into jumpspace - so dropping the tanks just after powering the grid would leave big lumps of the ship surface uncovered by the now-deformed jump grid. Also, the grid has been powered, and the 'rip' opened for a certain distance jump, dropping the tanks afterwards would have 'unspecified' effects...

Theoretically, IMTU, a dispersed structure, with the jump tanks on the end of a long sponson could risk charging the grid, jettisoning the tanks, and trying to jump with an incomplete jump grid, but it would add at least +6 to the misjump roll - it might be used in an emergency, but you wouldn't rely on it for regular cargo runs!
 
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