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Is this 'legal'?

I'm probably missing something here, there has been something of a debate over the economics of various merchant vessels..

Heres my take on it.

Design a USL open frame hull, fit the required jump drive to, and power systems.. then dig up 'Hard times' and fit a non gravetic drive, mostly as a low acceleration thrust system for docking etc.

Now this thing is strictly orbit -> orbit, using either local shuttles or one it carries to move cargo containers as required. It has little STL trhust capacity, but then *doesn't need it* its a box, moves slowly to 100 diameters, jumps, then moves slowly to an orbital station, or just into orbit so the shuttle can handle the rest of it.

The only two bits of the design above TL8 are the jump drive and the computer, which keeps the CP requirements down.

Thus the ship has limited capabilities, but is cheaper to by and cheaper to run. Its not dragging a thruster system round it doesn't need.

I can find nothing in the rules that makes this illegal, but then maybe i've missed something.
I don't think there'd be any reason it's not done. In T20 I've been opting for a close structure and upgraded streamling for a similar reason.

In fact on a supported route you could concievably have a Merchant Boat (ala X-Boat fashion) with just Jump drives.

You can save even more money in T20 if you allow that the computers listed are the version at that TL and you buy your TL5 model/1 computer at TL9 as a standardized design and save 90% on the computer. I don't allow it myself for various reasons but by the letter of the rules it would be reasonable.

And of course for such a low budget Merchant ship you aren't going to add any hardpoints to save a few more creds.

Lots of cost cutting methods depending on the specifics of the route.
I'd say it was legal.

I played with a similar idea with T4, I figured that you could ditch the M-Drive and just use the CG built into the hull as a thruster until it reached 10 diameters out where it cut-off due to distance. Of course, it was pirate bait and so was only used in stable and patrolled systems.

I don't believe that T20 ships have built-in CG, but then again there is nothing saying that they do not either.
Jeff: TNE/T4 CG can't do that; it negates the 99% of the acceleration generated by gravity, but does not, itself, produce thrust.
You can always jump to 100 planetary diameters with zero vector and then let gravity do its thing ;)

It'll take a while to make it to the planet, at which point how do you slow down with CG?
Originally posted by Aramis:
Jeff: TNE/T4 CG can't do that; it negates the 99% of the acceleration generated by gravity, but does not, itself, produce thrust.
I thought that only the TNE didn't produce thrust and that the effectiveness of T4 CG went down by the square of the distance from the body it was using to repel against?

I don't have FF&S2 to doublecheck this, but I confirmed the TNE stuff through FF&S1. Crap, that would mean I'm back to M-Drives for T4 again....
Hang on a second.

I just looked at Central Supply Catalog (T4) and it says that CG both negates surface gravity and provides thrust, but only out to 1 planetary diameter. This still works, because at a default 1.1G where 1G is used to negate gravity and 0.1G is used for acceleration, you can still reach escape velocity for a world before exceeding the 1 diameter limit of that world.

Huh, with the right navigation instruments and life support, you could theoretically use an air/raft for interplanetary travel. Hey! I could see this as a combination marathon/survivor sporting event! Nifty!
You're quite right, T4 put gravitic thrust back into CG:
</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">TL type thrust factor
9 standard 0.08
10 improved 0.12
12 high efficiency 0.16 </pre>[/QUOTE]Adapted from Table 164, page 105, FF&S2.
"Back into it"? No, this is simply not CG.

ANTI-gravity is supposed to be a thrusting agent; pushing against a gravity well.

CONTRA-gravity is supposed to be gravity nullification, eliminating the gravity vector.

Some time ago, some one tried to insist to me that phsycists or some other brainiacs insisted "there's no such thing as deceleration, only negative acceleration (meaning acceleration in the opposing direction)".

My refutation: Drive your car at say 20 MPH. Shift into reverse and press the gas pedal. THIS is negative acceleration. Your velocity relative to the earth is changing, you at first slow down until you stop, but then you start going backwards, because you are imparting a force to accelerate, but in the negative direction.

Now, travelling at 20 MPH again, apply the brakes. Eventually the car comes to a stop (relative to the earth) and does not begin moving in another direction, no matter how hard you push that brake pedal. THIS is deceleration, which is application of friction - NOT ACCELERATION - to reduce the relative velocity between you and something else. While the two are very similar, they are not the same thing.

By the same token, ANTI and CONTRA grav, in terms of Traveller, are not the same thing. One provides thrust, but you are still subject to the gravitational vector of what you're thrusting against, the other simply makes the gravitational vector go away (or very nearly so). One repels gravitons, the other renders them inert.

It is natural to be confused by this, because ANTI and CONTRA mean the same thing. Whoever invented the term should have come up with something else, like maybe Null-grav, which is something I use now and then.

One last point of confusion would be ARTIFICIAL gravity, and this is the generation of gravity for the comfort of passengers, not a thrusting agent in and of itself (though through inventiveness you could probably get it to do so).

That T4 went and made this change shows further that they didn't know what they were doing, but since not many people use it for more than its setting anyway, it's not a big deal.
But as to the actual topic, no it's not illegal, else you would be in jail! Ha! Okay, anyway, yes you can do that, but you don't see it in the majority of Traveller work, probably because the notion of free acceleration is a very powerful one, and not readily given up.

Ships which can constantly thrust at 1G or more don't need to be frames; it's a lot cheaper (in time and money) to just fly the ship to the world. Modularizing ships and having them all do business at the 100D limit means more expense. You need more people to man all the little runabouts and shuttles, you'll need a way-up-port or 10 to handle all the traffic out there, and fuel shuttles, and I'm sure lots of other things.

So what does doing it that way gain you? Well, I suppose if you only had ONE shipbuilding facility, it would make sense. All your ships are based off the same components, so that any ship can have parts interchanged with any other (well, probably an 80% success rate, which would be phenominal from a supply standpoint). It is a lot easuer to have an assembly line assembling ONE kind of thing than to have it shift between projects.

Another possible gain is that, as your cargo needs increase, you simply increase the sizes of the modules your ships carry rather than building all new ships. Much easier/cheaper to make a box than to make a complicated ship. Assuming your jump drives are modular and simple, you might need to add another jump drive module to a ship to get it to perform the same when it's larger, but I really doubt anyone assumes jump drives are THAT simple.

As the number of ship building centers increase, it makes less and less sense to continue to do this, and more sense to just build a specialized and more efficient ship for a given task. So I would say that your modular ship idea would be useful and make appearances in pocket empires, but not the Imperium as a whole.
Originally posted by TheDS:
"Back into it"? No, this is simply not CG.

ANTI-gravity is supposed to be a thrusting agent; pushing against a gravity well.

CONTRA-gravity is supposed to be gravity nullification, eliminating the gravity vector.
Unfortunately, the people who wrote the game disagree with your definitions ;)

By the same token, ANTI and CONTRA grav, in terms of Traveller, are not the same thing. One provides thrust, but you are still subject to the gravitational vector of what you're thrusting against, the other simply makes the gravitational vector go away (or very nearly so). One repels gravitons, the other renders them inert.

It is natural to be confused by this, because ANTI and CONTRA mean the same thing. Whoever invented the term should have come up with something else, like maybe Null-grav, which is something I use now and then.
In CT the were called originally called null grav modules in the description of the air/raft. This was shortened to grav modules at some point.
They negate gravity and provide thrust.

They work this way in MT too ;)

It was TNE that changed the paradigm and brought in CG lifters and removed gravitic thrust.

T4 tried to undo some of the damage that TNE had done to the CT tech paradigms (which are also used in CT/MT/GT/T20), while also allowing the ships etc. built using TNE to remain within canon.
T4 FF&S2 has both TNE style CG (which negates gravity-induced acceleration) AND Gravitic thrusters.

Greg Porter, who did Emperor's Vehicles, did not use the FF&S terminology, and muddled the mix.
Hmm. A "merchant rider" type thing might work, you'd have have a frame with a Jdrive and a power plant for it, and that's it. Attached to the frame is a ship with maneuver thrusters and cargo space, staterooms, etc. You can get away with less maneuver drives/cargo capacity because you don't have to push the jump drive in and out of the 100D limit. Unfortunately you do need to carry enough fuel tankage on the lander subship to fuel the jump frame.

If you want to go a step farther, you have several of these working a route, and a lander module with full cargo and fuel waiting for the arrival of the jump frame at the 100D limit. Empty lander leaves for the planet, full one docks with jump frame and immediately jumps.

Take it even further, and you have dedicated sublight ships at each system waiting at 100D to refuel the frame and attach/remove cargo modules. Then you don't need to carry maneuver drives at all.

You could design one Jframe around all of the above, and you use different cargo/lander/fuel configurations depending on how established the area you're working in is. Frontiers, you carry one lander around. Short routes you set up a few J-Frames and rotate the landers. Routes with such high traffic that it would be profitable could have permanant bases established that would handle the dedicated shuttles for each system.
I have been looking at going a step further.

Long haul cargo stations are out in deep orbits. you only need to get 100 diamiters from the FUELING PLATFORM. Then cargo is loaded and unloaded at the platform, and in-sytem transports carry it to the local worlds.

That conveniently means that those super deep space transports have always been around, just never "seen" becuase travers arn't interested in something as mundain as a bulk carrier that is 2 days in-system travel from anything more than an automated refuling port and and some cargo monkeys.

then you are back to virtually no manuver drive. (how much drive to you need to move a couple of kilometers to jump, and the same back at the detination.) Ok, if you want to follow the rules for jump variance then you need either a man-1 with just enough fuel to get you to dock if you miss the target, or tugs to catch the occasional out of range jump.

Just something I have been toying with.

Mr tek
So you eliminate the m drives. Now what happens if you miss jump, or someone on one of those "insystem" shuttles is a pirate, or a thousand other little things?
Long and short answers:

Misjump M-drive is meaningless anyway.

Why is a pirate going to go tothe trouble to desguise himself to blend into the depot, way out in BFE, to hijack 300,000 crates of widgets to make mark 38 vac suits, or 1/2 million tons of spam.

AHH... what about more valuable cargo? Now you suddely have adventure hooks. Any long haul truckers or longshoremen care to disscuss theft and "misrouting" at long haul terminals and truck stops?

Those other thousands of things that can go wrong?

A: on that standardised a cargo run, if any of them go that wrong, you are screwed way beyound the little bit of travel time saved by having the drive. and

B: In most of those cases, having an M-drive would not make a differnce either way.

and finally

C: 15% estra cargo space, on a flying warehouse, plus fewer crew not having to post the enginerrs.

At some point long haul shipping is a numbers game, and spoilage, (theft, bookeeping errors, equipment failures, spoilage due to excess transit times, accidents, and all of the typical snfus we all know and love burrocracies for,) even to the point of lost ships and crew is more than made up by the gargantuan movement of cargo from point a to b.

(think, as a net exporter of food, how much food travels both directions through US ports, PER DAY. There are long lines of 100,000 ton and larger ships at dozens of ports around the country. Could a whole planet even live on a few hundred 50,000 carriers in and out of port, EVERY SINGLE DAY? and still handle cargo tranisting through bound for other worlds?

The decrease in trafic control alone would be huge. (of course the high ports and low ports at the main world still has to funnel the insystem rigs, but again, those dont need jump, so they can carry lots more and the transiting traffic is safly out of harms way.)
the idea is for the ships that move to dull stuff around, pirates? well the ships are worth more in bits than the cargo is, plus as designed they tend to hunt in packs probably with an escort.

I've knocked up a sample design, just can't get at the spreadsheet right now.. Bascially a TL-8 100DT open framed 'box' Can pull 0.9G for about 4 hours if it has to, with a more sensible 2 weeks crusing at 0.22G for in system work. Life support is factored for a 3 month voyage..

Its amazing how much cargo that 1350Kl hull can hold.. in this case around 1000Kl rated at 1000 tons.

Crew of four, a small fission reactor provides nominal power levels, apart from the drive..

Ah yes the drive... TL8 experimental fusion drive wonderful bit of tech.

Yeah sure this thing can't land (don't need to) and it had trouble out running a milk float, but then given it would need 4-5G to outrun a pirate anyway, which ain't gunna happen does this matter?

Crew of 4.. who probably need some time away from each other at the end of the voyage.

This is a simple mockup, I'll post the full design when i can get hold of it.. for anyone who fancies:
a, a bit of low tech
b, a real cheap way of moving things about
or more probably
c, target practice.. naturally its unarmed.

How hum the 10,000DT version is in the works once the spreadsheet is fully up and running :) Automatic fuel optimisation.. don't cha just love it
Clare, if you don't care about speed then change the experimental fusion drive to a solar sail and just sunjammer your way around the system.
Of course, there is the little issue of mixing MT hardware into *ANY* other edition...

Low-cost M-Drive options really vary with the edition.

In CT there really are no published options, as the ship design mechanics are all somewhat abstract. If you can stretch the HG formulas to do fractional G drives, though, that's the way to go.

Same with MT, though the effects will be *MUCH* stronger in MT because of the cascade effect from cutting by half (or more) the single biggest power using system in the ship. If you are also going for unarmed, the powerplant will shrink to almost nothing. At this point, you really don't need to go econo on the hull, because the ship has already shed a LOT of construction cost...

TNE had thrust-less CG because it's M-Drives didn't use AG technology at all, but AG is canon for the OTU. If you are using TNE as your base, a variety of alternate drives are available. HEPlaR is wildly efficient, however, and a fractional-G drive is at its most viable in TNE.

T4 allows for both HEPlaR and Thrusters in canon, a simple adjustment that makes T4 a favorite technological framework for me despite the bugs.

I will plead relative ignorance of G:T. I own it, but SJG books give me hives for reasons that go far beyond his version of Traveller.

T20 returns to a very HG-like model. Make it up.

As for "legal", it's only illegal if you want to publish, and then only if you can't explain it properly...
Ok a grab of a webpage..

I present the...

Foxtrot Class Light Merchant
Craft ID Foxtrot Light Merchant, Type AAL, TL 8, MCr1,298.00086
Hull 900/2250, Disp 1,000, Config 0USL, Armour 40C
Unloaded = 5525 Tons, Loaded = 17704 Tons
Power 3/6 Fission = 20MW, Duration = 56 Days
Loco 100/200, Ex Fusion Rocket (18,000TT), 1.01G (28 Days), STL Only
Commo Radio (system) x3, Laser (far orbit) x2
Sensors Radar (far orbit) x2
Act Obj Scan = Routine, Act Obj Pin = Routine
Pas Obj Scan = n/a, Pas Obj Pin = n/a
Pas Eng Scan = n/a, Pas Eng Pin = n/a
Off Hardpoints = 10, no weapons mounted as standard
Def Def DM = +3, no defensive systems mounted as standard, EMLevel = Faint
Computer (2/bis) x7 [+ x7 more as backup], panel = Electronic Link x1,000
Basic Env, Basic LS, Ext Ls, All for 2700 Kl of hull (habitation areas & internal cargo bays only - NOT engineering areas)
Accom Crew = 4 (bridge x2, engineering x2), staterooms x4
Other Hydrogen Fuel (for drive) 204Kl, Radioactive Fuel (for reactor) 54Kl [within reactor housing]
External cargo modules (100DT rated @ 1350Tons) x8, Internal bay #1 (100DT rated @ 1350Tons), Internal bay #2 (29Kl rated @ 29Tons)

Built around a triangular cross sectioned longditudinal trust, to which other components are mounted, the Foxtrot Class light merchant is common within the Sword Empire. Operated both by private concerns and Green Sword Logistics Command for the navy.

To date some 140 vessels of this class have been deployed within the Sword Empire.

Designed to operate with eight standard 1,350Kl cargo modules. Each rated at 1,350 Tons along with an further 1,350Kl internal cargo bay in a dorsal pod adjoining the small accomodation areas. A second internal bay is limited to 29Kl and is normally used to store small packages and/or supplies.

The Experimental Fusion drive provides a respectable 18,000 Tons fo Thrust and sufficient propellent/fuel is carried to allow this to be maintained for 28 Days providing a shade over 1G acceleration. It is normal to use the 60MW power output when the drive is operating to run the craft, a small Fission reactor rated at 20MW provides sufficient power to operate the vessels limited systems when the drive in inactive. Reactor fuel is carried to allow for a 56 Day trip at the rated 20MW power, typically this is extended by upto the drives rated 28 Days for a normal endurance of 84 Days. Which can be further extended if required by reducing power requirements of the craft in operation.

The craft operates with a small crew of four, two bridge crew, typically one pilot/commander and one navigator/electronics operator. A pair of engineering crew maintain the drive and reactor, typically one is a fusion drive specialist and maintains this technology, the other crew man maintaining the operations of the reacotr and other ships systems.

The total habitable areas of the craft comes to a little more than the 216Kl from the four staterooms, this is a cramped vessel and as a result some of cargo bay #2 is normally utilised for a recreation area.

Normal operations are limited to orbit - orbit transfers, the Foxtrot has no landing capacity at all, even though it has the required thrust it lacks the capacity to vector this for landing and the frame is not designed for the stresses of landing being braced in the direction of thrust only. Typically the craft will have the eight cargo modules swapped out while the main bay is unloaded of its payload of smaller containers. Normally the crew will serve for one trip, the be replaced with a second crew. They then await the arrival of the next vessel, this is modified for visits to smaller outposts with the same crew handling both directions.

For longer ranged trips it is possible to provide for additional drive fuel within the internal cargo bay, the external modules lack the capacity to be hooked to the fuel or even energy grid. It is worth noting that the craft lacks the capacity to refuel the fission reactor since this requires specialised handling equipment. (This could be carried in one of the payload modules if required).

For FTL transport the Foxtrot requires the services of a jump frame, the Sword Empire is somewhat limited with Jump technology but the foxtrot is designed with a docking couple built around one of the twin airlocks to allow for hooking up to an Orion class Jump Tender


Ok so its not brilliant, but it works, and given it can haul just over 900DT of cargo i'm happy with it