Jump Frame and barges freighter

[McPerth]

This is an example of what I posted in another thread:

For the true megafreighters, I envision them as pure skeletical jump frames where "smaller" (I'd say up to 1000 dton) barges able to land could be attached. For regular routes, the jump frame just arrives to orbit and the barges dettach and land to be unloaded, while similar barges already waiting loaded in the world attach themselves to it and it's ready to go away again. That way all interface is "self contained" by the company and the loading/unloading could be done dirtside, so shortening the time the jump frame must be in orgit to th time for itself to refuel and for the barges to dock/undock.

To save in ship crew, the barges could be crewed by people in the world and make the roud trip or even be robotic (no crew at all), and each one being a self-contained boat.

Even some of them could be passenger carring, so slowing the time for passenger boarding and, if swaping jump frame, you'd be able to go a whole route in the same barge even if the barge itself has to swap frame several times along the route.

It has been designed with MgT CB system (not the megafreighter told about in the post, it should fit in a MgT small ship universe) to keep it simple. The only extra added from MgT HG is the docking clamps, as I found them quite important here. To think about the true megafreighter, it should be scaled up.

Star Class Jump Frame:

Item	Notes	Tons	Cost(MCr)
2000 tons distributed hull	Hull:40 Structure:40	.	180
Jump Drive=U	Jump=4	100	190
Maneover Drive=K	Maneover=1	19	40
Power Plant=U	Power=4	58	152
Bridge	.	40	10
Computer	Model 3 (bis)	0	3
Electronics	Basic Civilian (-2)	1	0.05
Fuel	PP 2 weeks	38	.
Weapons	1 HP with triple PLaser Turrets	1	2.5
Crew Staterooms	9	36	4.5
Extras	Ship Locker	0	0
.	Escape pods x 9	4.5	0.9
.	Luxuries	2	0.2
.	Repair Drones	20	4
.	Clamps for 8 200 ton barges	80	16
.	8 x 200 ton Barges	1600	Barges’
Software	Maneover	0	0
.	Jump Control/4	0	0.04
.	Auto-Repair/2	0	10
.	Fire Control/1	0	2
.	Library	0	0
Cargo	.	0.5	0
Totals	.	2000	560.1505

Crew is 3 pilots, Navigator, 3 engineers, medic and 1 gunner.

Weaponry is mostly to be legally labeled as armed in order to carry mail runs. It may also be used to avoid debris/meteor damage.

It carries no jump fuel, depending on fuel barges for it. It needs 1 full fuel barge plus 20 tons of fuel on another per parsec jumped. Its own fuel is a reserve, also depending on fuel barges for regular use.

The luxuries for the crew are a rarity, and are to ease life for a crew not expected to land for quite a time, due to operative schedules of those ships (aside that there were 2 tons left, not enough for anything worth it).

 

[McPerth]

Cargo/fuel barge:

Item	Notes	Tons	Cost (MCr)
200 ton hull	Hull:4 Structure:4	.	8
Streamlined	.	.	0.8
Maneuver Drive=A	Maneuver=1	2	8
Power Plant=A	Power=1	4	16
Fuel	4 weeks	4	0
Bridge	.	10	1
Computer	Model 1	.	0.03
Electronics	Standard (-4)	0	0
Software	Maneuver	.	0
.	Intellect/2	.	0.05
.	Expert Pilot (spacecraft)/3	.	0.1
Cargo	180 tons	180	0
Totals	.	200	31.0118

The cargo/fuel barges are fully robotic, relying on ground/frame engineers or drones for maintenance/monitoring. The cargo space may be used either as fuel or as cargo/freight, as needed.

 

[McPerth]

Passenger barge:

Item	Notes	Tons	Cost (MCr)
200 ton hull	Hull:4 Structure:4	.	8
Streamlined	.	.	0.8
Maneuver Drive=A	Maneuver=1	2	8
Power Plant=A	Power=1	4	16
Fuel	4 weeks	4	0
Bridge	.	10	1
Computer	Model 1	.	0.03
Electronics	Standard (-4)	0	0
Software	Maneuver	.	0
Crew staterooms	10	40	5
Passengers Staterooms	30	120	15
Extras	Scape pods x 40	20	4
.	Luxuries	2	0.2
Totals	.	200	52.8973

Crew: 1 Pilot, 1 Engineer, 7 Stewards, 1 Medic. Engineer uses to be specialized in life support, as this is his main function.

 

[McPerth]

Appearence:

may vary, but I envision it as an octogonal saped jump frame and needle/wedge configuration barges (externally symilar to an enlarged scout). One such barge would clamp in each side of the octogon, so, when all 8 barges are clamped it takes the shape of an 8 pointed star (more or less like two NATO stars superimposed).

Operations:

This class of ships use to jump among high pop developed systems, were the barges may be served. Usual operations is for regular schedules, so that the barges may be filled before the ship arrives, and take off when the ship exits jump space, waiting for it to reach orbit, where they exchange for those attached to the ship.

The just detached barges land to be unloaded, while the jump frame, with the new attached barges, go to jump vector and jumps again, usually staying in system less than 24 hours. This allows about 3.5 jumps a month as average.

Once on ground, the barges are unloaded, served, and loaded for the next ship to arrive. The fact that the ships arrival and route is regular allows for them to be prepared for the needs of the same jump (cargos and passengers destined to the next world, exact load of fuel/cargo, etc.).

Economics:

Assuming one passenger barge, a ship has 7 cargo/fuel barges that allow it 1260 tons of cargo/fuel. This uses to include the fuel for the next jump plus 2 weeks PP (the one in the jump frame itself is a reserve), the rest being filled with cargo:

Jump 1: 30 high passengers, 238 tons of fuel and 1022 tons of cargo. Revenue: 1202 KCr (1083 discounting fuel cost)

Jump 2: 30 high passengers, 438 tons of fuel and 822 tons of cargo. Revenue: 1346.4 KCr (1127.4 discounting fuel cost)

Jump 3: 30 high passengers, 638 tons of fuel and 622 tons of cargo. Revenue: 1470.8 KCr (1155.8 discounting fuel cost)

Jump 4: 30 high passengers, 838 tons of fuel and 422 tons of cargo. Revenue: 1575.2 KCr (1156.2 discounting fuel cost)

At 3.5 jumps/month, income (once fuel is paid, if full with freight and High passengers) would be from 3790.5 to 4046.7 KCr

Operating monthly costs (mortgage, maintenance, life support and salaries) are 2478 KCr per month for the jump frame, 127.55 KCr per cargo barge and 329 KCr per passenger module, for a total of 3699.85 KCr/month.

Of course, those numbers may be misleading, as more than one set of barges and good dirtside infrastructure is needed per jump frame to keep with the schedules, but it neither includes speculation, easily made from the ground support facilities.

 

[mike wightman]

I like it - thanks for posting

 

[Garyius2003]

The barges make sense in some circumstances. GURPS had a great idea for lighters at the jump point. Ship comes in, loses the lighters meant for that planet, drives to the outbound jump point, is met by outbound lighters and fuel. Gets an extra jump out of the ship.

The downside is needing to move containers from one barge to the other, because of different final destinations.

I have been playing with the idea of very large (500k) J4 core area jump ships, which would haul a standard size barge. That barge would also be the same size as a battle rider, the ship would be made with fittings for extra weapons and meson and black globe in addition to the damper.

For the next Rim War call up some of the ships, riders on some, troop pods and cargo pods on others. The 3I gives some incentive (sort of like the old US Civil Air Reserve fleet) to the megas to do business that way.

The issue is, without a VERY good reason such as the two listed, why would you use barges? Unless you have truly two point shipments, you will have to move containers from one barge to the next, and 3I has robot container movers. As fast as modern ports are moving containers, the 3I port must just be incredibly fast.

If the ship is already going to the highport, and needs some quick refuel and restocking of life support and chow and parts, and the J arrival uncertainty time is already 18 hours, why not take 18 to unload the containers for that port and load the outbound?

 

[McPerth]

The key of succes for those ships is planification (probably a Vilani design ), and the cargoes should be distrubuted in the barges according to final destinations to avoid this transshiping among barges.

The main advantage is the small time spent in real space. The fuel, life support, etc. needed by the frames should be loaded with the barges, that must be ready at the earliest expected time for the Jump Frame. Even passengers shuld be loaded in the passenger barge by then (after all, they could be totaly oblivious about if they are landed, in transit to the Jump Frame or attached and in jump space, if all works well, so having them loaded some hours earlier than the barge take off will not be a problem).

See that barges making more than one jump with the frame need not to be detached, and fuel can be redestributed from a fuel barge if needed, as can other supplies for a passenger barge making more than one jump in a row.

 

[Dragoner]

ISCV: Leander

Leander is a variable tonnage cargo ship with a 600-ton drive
unit and up to ten 200-ton cargo barges.

1st instance iirc.

 

[Garyius2003]

Figure most of the time the incoming ship will be 1G, and 8-12 hours out from the highport. Almost all versions of highports use a docking method (internal or external).

That means the loadmaster has at least 8 hours to refine the staging plan and preposition the outbound, aided by software which plays container tetris with perfect accuracy.

Ship arrives and docks. Massive gravbot (drone in Mongoose) cargo frames swoop in as yellow warning lights revolve and the final vapor of docking wisps. With unerring efficiency they clamp on, and as quickly as a subway leaving a station they shoot though a hatch to a staging area, moving 4, 6, and 8dT containers as quickly as I pick up legos.

With three bots a 100 ton barge/hold could realistically be unloaded and reloaded in a half hour. With a second (or third) hatch and larger hold more bots would help, but 18 hour load times even for a huge hold is very doable. The barge just does not save all that much time for the trouble.

I do think the Mongoose clipper with the changeable modules makes sense for different routes and charters in semi frontier areas, as long as you rule the shuttle can be deleted in favor of another cargo area. However, I think the advantage there is ease of role revisions for the ship, not for cargo handling.

 

[DaveChase]

Well something similar but not directly

I have ore processing plants in some of the large belt area of mining that produce metals in the shape of modules (30 ton and 50 ton and 100 ton and 1000 ton)

These have fitting built into them for the correct connections to a module carrying ship.

No lifesupport or power supply is need so if they are hooked into a chain the power/lifesupport modules need be hooked into the ship first the ore modules last.

Also the ore procssing plant makes hollow containers similar to the empty module but they are only for hold other by product from the plant and use iron ore for the shell. They are not functional as a empty module.

Dave Chase

 

[rancke]

Of course, those numbers may be misleading, as more than one set of barges and good dirtside infrastructure is needed per jump frame to keep with the schedules, but it neither includes speculation, easily made from the ground support facilities.

There's no 'may' about it. The cost of the ship will include at least one full set of extra set of barges plus the cost of operating them.


Hans

 

[McPerth]

Figure most of the time the incoming ship will be 1G, and 8-12 hours out from the highport. Almost all versions of highports use a docking method (internal or external).

That means the loadmaster has at least 8 hours to refine the staging plan and preposition the outbound, aided by software which plays container tetris with perfect accuracy.

Ship arrives and docks. Massive gravbot (drone in Mongoose) cargo frames swoop in as yellow warning lights revolve and the final vapor of docking wisps. With unerring efficiency they clamp on, and as quickly as a subway leaving a station they shoot though a hatch to a staging area, moving 4, 6, and 8dT containers as quickly as I pick up legos.

With three bots a 100 ton barge/hold could realistically be unloaded and reloaded in a half hour. With a second (or third) hatch and larger hold more bots would help, but 18 hour load times even for a huge hold is very doable. The barge just does not save all that much time for the trouble.

As you hint here (or at least as I read your post) one of the main limiters to the loading/unloading the cargo hold will be the hatch and staging area sizes. Also, what you say needs such facilities in high port, while the frame/barges here presented may even work withut any high port, being fully independent in this sense (but they need ground support for the barges and trade).

I do think the Mongoose clipper with the changeable modules makes sense for different routes and charters in semi frontier areas, as long as you rule the shuttle can be deleted in favor of another cargo area. However, I think the advantage there is ease of role revisions for the ship, not for cargo handling.

You understand here two of the main advantages of this frame/barges combo. As told above, the independecy from highport (that's what I understand when you say the use in semi frontier areas), and its adaptability to the needs of the moment (more or less fuel, more or less staterooms, more or less cargo space)

To compare with the Heavy Freighter depicted in CB page 125, using the frame/barges combo in jump 2 to better compare:

Advantages for the Heavy Freighter:

-Frame/barges combo has a little less cargo space (with 438 tons of fuel, it has 1002 tons for cargo passengers, a 50.1% of its volume versus a 55.2% for the Heavy freighter).

-Frame/barges combo is more expensive (the full combo costing about 4 times what two Heavy Freighters).

-Frame/barges combo needs more ground infrastructure to operate at maximum efficiency. Of course this is not a player's ship, but a subsector and up (more up than subsector) sized company.

Advantages for the Frame/barges combo:

-Adaptability. May convert some of it to passenger space.

-May operate without interface (orbit to ground) support.

-Quicker to load/unload if it has the pertinent ground infrastructure. See that it could work without it, but would lose most of its advantage, the barges will have to land, load/unload, and return. Probably would be able to do it and keep the jump per 2 weeks ratio, though.

-Of course, may use jump 4 capacity.

 

[McPerth]

There's no 'may' about it. The cost of the ship will include at least one full set of extra set of barges plus the cost of operating them.


Hans

Not necessarly a full set of extra barges per ship, but sure at minimum one per port of call (and probably some more).

 

[rancke]

Not necessarly a full set of extra barges per ship, but sure at minimum one per port of call (and probably some more).

Any barge you don't exchange for another at a port of call is a barge that is not generating revenue that jump. The whole point of a LASH setup is to have the insystem travel performed separately to allow the ship to jump out faster.

If the volume of trade is high enough, several ships may share the same extra set of barges, but on the other hand, if the volume of trade is too low, the barges in the system may be underutilized. Say, for example, a ship jumps back and forth between two systems: You'd need an extra set of barges in each system, for a total of three sets.


Hans

 

[McPerth]

Any barge you don't exchange for another at a port of call is a barge that is not generating revenue that jump. The whole point of a LASH setup is to have the insystem travel performed separately to allow the ship to jump out faster.

If the volume of trade is high enough, several ships may share the same extra set of barges, but on the other hand, if the volume of trade is too low, the barges in the system may be underutilized. Say, for example, a ship jumps back and forth between two systems: You'd need an extra set of barges in each system, for a total of three sets.


Hans

You're right in your statements except the point underlined. If a barge stays with the jump frame for 2 jumps that means the goods/passengers have paid for 2 jumps, so revenue is generated anyway.

The barges sharing is one of the basis for the system to work, and you're right in that this would only work among high volume of trade systems (let's say about 2-3 ships covering each 2 systems route), but the fact they can go up to jump 4 allows them to choose the ports of call to be high volume of trade routes.

 

[silversides207]

I am curious as to exactly what sort of cargo you are planning to put into the barges, and for that matter, some of the megafrieghters being discussed on other boards.

Typical bulk cargoes in the Real World are petroleum, grain, coal, ore (iron, aluminum, etc.), and on the US Great Lakes, limestone, concrete, and salt. I cannot see a massive amount of interstellar shipments of petroleum, coal, or ore, and I have serious questions about massive amounts of grain being moved. That is probably because I regard high-population worlds under hostile conditions as to be extremely unlikely, and the result of blind use of die rolls when it comes to population.

Any world government is going to try and make itself as self-sufficient as possible given the limits of its resources and technology, if for no other reason that to keep its population employed. Imports also have to be paid for, and a constant deficit in its interstellar trade balance is eventually going to cause major financial problems for a world.

 

[McPerth]

Just realized: The costs for both jump frame and barges are unadjusted for standard designs, not architect fees have been accounted for.

As they need to be standard designs for the whole concept to work, prices (and so maintenance and mortgages must be reduced by 9%.

EDIT: Edited now, as well as fixed the passenger barge cost (I botched it). Now they should be correct, to the best of my knowledge and intent (if I didn't fail in anything else)

 

[McPerth]

I am curious as to exactly what sort of cargo you are planning to put into the barges, and for that matter, some of the megafrieghters being discussed on other boards.

Typical bulk cargoes in the Real World are petroleum, grain, coal, ore (iron, aluminum, etc.), and on the US Great Lakes, limestone, concrete, and salt. I cannot see a massive amount of interstellar shipments of petroleum, coal, or ore, and I have serious questions about massive amounts of grain being moved. That is probably because I regard high-population worlds under hostile conditions as to be extremely unlikely, and the result of blind use of die rolls when it comes to population.

Any world government is going to try and make itself as self-sufficient as possible given the limits of its resources and technology, if for no other reason that to keep its population employed. Imports also have to be paid for, and a constant deficit in its interstellar trade balance is eventually going to cause major financial problems for a world.

More or less the same cargo shipments that in any other ship (plus passengers on demand).

While I understand your doubts, they will apply to the full concept of interstellar trade, quite basic in Traveller universes concept (not only in OTU), not just to this design.

Traveller assumes those large shipments are regularly traded among worlds, as it assumes hostile worlds can be high population ones (Glisten is a good example). If we rule it out, whole sections of all Traveller rules sets (the ones about trade and commerce) are voided of meaning, as are many adventures.

Of course, all of this may vary in YTU, and then probably this (and most, for what is worth) merchants lose most of their meaning, except passenger lineers. But even then this same design could be used mainly as passenger ship, cargo barges being used mostly for fuel.

 

[rancke]

You're right in your statements except the point underlined. If a barge stays with the jump frame for 2 jumps that means the goods/passengers have paid for 2 jumps, so revenue is generated anyway.

That would only be the case if this is a regular feature of the run. If you occasionally need to drop off the barge in the intermediate system, you need the extra barge for those occasions. If you never need to drop it off, you're right. But then, the advantage you gain over more conventional ships is less, since such ships would need to spend time unloading and unloading in the intermediate system either. And conventional ships carry more cargo than you do.


Hans

 

[whartung]

The biggest advantage of a "Freight Rider" or Jump Frame is turn around time.

The ship jumps in the staging area is setup right there at the 100D limit. As soon as it has stabilized, it kicks off the modules destined for the system. The outbound cargo modules are waiting for the ship and are loaded up post haste. Tankers fuel the ship in place. The crew, if appropriate, is rotated out and the ship prepared for a return or its next leg.

This saves the whole 100D trip and turnaround, everything is loaded and unloaded as quickly as possible and the ship spends as much time in Jump as it can.

It's not really appropriate for passengers because passengers aren't going to sit lingering out at the assembly point waiting for the ship. Passengers need a tighter and more predictable schedule than freight does. Passengers need a "Leaves on Saturday at 10am" rather than "sometime on Sunday" or "we will tell you in within 24 hours of departure the actual departure time". It's basically crummy service.