T5 Book 2 Big Ships

[mike wightman]

Just as well it is in JTAS 24 then. and he has written the same article for MgT in JTAS vol1 issue 2which posts dates T5...

or are you also saying MWM contradicts his own universe?

 

[tjoneslo]

he has written the same article for MgT in JTAS vol1 issue 2which posts dates T5...

This article is a simple reprint of the original JTAS 24 article. In the first six issue of the MgT JTAS are several articles simply reprinted from the original JTAS article. Some with minor updates to the technical information. So I'm not sure Marc re-wrote or updated the article, just Matt reprinted the article from the original publication.

 

[AnotherDilbert]

His jumpspace article, which i consider definitive, states that the hull needs a network of cables, nothing in T5 contradicts or overwrites this.

As quoted it's explicitly expanded:

T5 B2, p113:
Jump Bubble
Without any additional mechanisms, the Jump Drive creates a quasi-spherical (often an egg-shaped oblate spheroid) bubble.
...
Jump Grid
A Hull equipped with Jump Grid has a mesh of jumpfield conductive wires just below its surface; the Jump Drive effect is channeled through these elements to create an efficient field which closely conforms to the shape of the hull.

CT (incl. the JTAS article) uses the Jump Grid, T5 (or some intermediary edition) added the Jump Bubble as an alternative.

 

[Condottiere]

The clue would be that a jump grid cabling compromises the strength of the hull armour, whereas the jump bubble doesn't.

Could there still be cabling, that doesn't compromise the strength of the hull armour? Seems doubtful, since external attachments don't require it for jump bubbles.

 

[Spinward Flow]

Jump Grid
A Hull equipped with Jump Grid has a mesh of jumpfield conductive wires just below its surface; the Jump Drive effect is channeled through these elements to create an efficient field which closely conforms to the shape of the hull.

CT (incl. the JTAS article) uses the Jump Grid, T5 (or some intermediary edition) added the Jump Bubble as an alternative.

And then you've got the LBB S9 example of the Jump Ship that uses a "jump net" of cables to extend the jump field beyond the confines of the hull ...

 

[AnotherDilbert]

And then you've got the LBB S9 example of the Jump Ship that uses a "jump net" of cables to extend the jump field beyond the confines of the hull ...

Yes, but that is outside any rules (except MgT2). We can only speculate that the jump cables fill the same function as the jump grid in the hull?

 

[whartung]

And then you've got the LBB S9 example of the Jump Ship that uses a "jump net" of cables to extend the jump field beyond the confines of the hull

I would surmise that the purpose of the "Jump Bubble" is just this kind of scenario.

Consider for example a dispersed structure modular freighter or Battle Rider carrier.

In order to compensate for gaps in the modular nature (i.e. consider a carrier returning from battle after losing 30% of its BRs), and to also, perhaps, simplify docking, not requiring modules to "wire up" to the grid, in fact not requiring modules to be cabled up at all, etc. The jump bubble contains the entire confines of the ships aura, including those things that are attached but no, perhaps, not "jump capable" as is.

Now, to be fair, I would argue the that "jump bubble" should be more inefficient than the jump grid. If it were me, I'd make the jump bubble cost 10-20% in additional volume. (So, for a 1000 ton ship, the bubble version would need a jump drive capable of pushing a 1100-1200 ton "bubble".)

 

[Spinward Flow]

Yes, but that is outside any rules (except MgT2). We can only speculate that the jump cables fill the same function as the jump grid in the hull?

What you call speculation, I call reading the explicitly written text published in an LBB and understanding the intent.

Now, to be fair, I would argue the that "jump bubble" should be more inefficient than the jump grid. If it were me, I'd make the jump bubble cost 10-20% in additional volume. (So, for a 1000 ton ship, the bubble version would need a jump drive capable of pushing a 1100-1200 ton "bubble".)

Sounds remarkably akin to making use of the small craft/big craft hangar space rules from LBB5.80, p32 ... the ones that say small craft occupy 130% of their tonnage and big craft occupy 110% of their tonnage on ships over 1000 tons. In a sense, then, the "surcharge" that you're talking about has already been paid for (10,000 ton ship needs 11,000 tons of parent craft tonnage allocation to berth), simplifying the considerations you're referencing.

The only real problem you run into then is with ships 1000 tons and under, where small craft are carried "at tonnage" (no surcharge) but large craft still have to pay the +10% tonnage premium to be berthed internally aboard (as part of the larger ship's overall tonnage allocation).

Of course, you would have to be an absolute WEIRDO to think there might be any "profit" to be had in external cargo stowage on ships of 1000 tons hull displacement or less, right?

 

[Condottiere]

The jump net was invented to extend the lanthanum grid, to non integral hull items.

The jump bubble appears to be a solution to simplifying the issue of non integral external attachments.

And apparently, the jump plates are a retcon to being the original way to establish a jump field.

 

[mike wightman]

There is no lanthanum grid. The lanthanum is used in the drive coils, not the cable network.

 

[robject]

T5 Book 2, Page 111 starts a chapter on How Jump Works.

Page 113 talks about the two different ways to express a jump field: as a jump bubble, or as a jump grid. This is essentially a design-time decision (and some hull configurations cannot have jump grids). Each gets an independent, separate section of text, and both sections are parallel texts that can be directly compared:

Jump Bubble	Jump Grid
[it works] Without any additional mechanisms	has a mesh of jumpfield conductive wires just below [the hull's] surface
creates a quasi-spherical ... bubble ... For most purposes, [it] is about five times the diameter of the [ship] and centered on the Jump Drive.	the Jump Drive effect is channeled through these elements to create an effeicient field which closely conforms to the shape of the hull
[it] imposes the effects of the drive on all matter within the bubble. [It] is well-suited to Cluster and Braced Cluster hulls, or the ships which may vary in shape from mission to mission. ...	Jump Grids cannot be effectively installed on Cluster and Braced Cluster Hulls. [p114] Jump Plates cannot be effectively installed on Cluster and Braced Cluster Hulls.
Occasionally, a Jump Bubble will enclose nearby debris. [These] other objects within the bubble suffer Jump Mishaps.	The Jump Grid has virtually no chance of misjump due to random nearby debris.
n/a	When a portion of hull containing Jump Grid is damaged, it is temporarily repaired by applying a bolt-on Jump Plate.

 

[robject]

Yes, but that is outside any rules (except MgT2). We can only speculate that the jump cables fill the same function as the jump grid in the hull?

I think that can be done with T5's jump bubble -- assuming that ship is more akin to a cluster hull than anything else. The jump field is centered on the jump drive, but it could be a dangerously large oblate spheroid.

The funny business -- which was pointed out to me maybe 20 years ago -- is how does the jump field know what the starship is? Without a jump grid, Traveller falls back on magic*. The jump field, somehow, is able to protect everything that qualifies as "ship" and not protect everything that is "not ship", even lacking a jump grid.

And in fact the whole T5 definition of a Jump Bubble requires that there is a quasi-magical division of the universe between "ship" and "not ship".


* OK yes, the jump grid is also magic. But you could argue some magical form of jump-conductivity. Of course once you've posited that, then you can, without pain, posit a form of normal-conductivity that the jump bubble could operate on.

 

[whulorigan]

And in fact the whole T5 definition of a Jump Bubble requires that there is a quasi-magical division of the universe between "ship" and "not ship".

I assume it just means that the Drive model installed in combination with the skill of the engineer projects a field large enough to encompass the vessel based on its settings. As you noted, a ship that will carry subhulls or act as a "tug" will require larger Jump-drives to encomapss the greater displacement when hauling its payload.

 

[mike wightman]

Surely the total volume of the jump bubble should be used to then determine the size of jump drive required.

A bubble 5 times the diameter of the ship means you can actually carry more ships in your bubble - seems like a way to avoid the 10% fuel per jump number not to mention you no longer need a tender, just a drive and a bubble in one of the battle riders will do the trick

 

[Condottiere]

1. My opinion, on the shape of jump bubble.

2. Would be that it can't exist in our universe.

3. That's created like a soap bubble, when a spacecraft with the jump drive goes down the rabbit hole into another universe.

4. It should be spherical, centered on the jump drive.

5. Teardrop would be conceivable, assuming external pressure and velocity.

6. If the jump bubble follows the general configuration of the hull, this sounds somewhat of a customization.

7. On the other hand, you can do this with jump plates.

 

[aramis]

I think that can be done with T5's jump bubble -- assuming that ship is more akin to a cluster hull than anything else. The jump field is centered on the jump drive, but it could be a dangerously large oblate spheroid.

The funny business -- which was pointed out to me maybe 20 years ago -- is how does the jump field know what the starship is? Without a jump grid, Traveller falls back on magic*. The jump field, somehow, is able to protect everything that qualifies as "ship" and not protect everything that is "not ship", even lacking a jump grid.

And in fact the whole T5 definition of a Jump Bubble requires that there is a quasi-magical division of the universe between "ship" and "not ship".


* OK yes, the jump grid is also magic. But you could argue some magical form of jump-conductivity. Of course once you've posited that, then you can, without pain, posit a form of normal-conductivity that the jump bubble could operate on.

Before SSOM, my explanation was that the bubble was resonated off a hull-shaped miniature of a "stability island" metal.

 

[Grav_Moped]

I think that can be done with T5's jump bubble -- assuming that ship is more akin to a cluster hull than anything else. The jump field is centered on the jump drive, but it could be a dangerously large oblate spheroid.

This is why I keep going back to prolate/oblate spheroid hulls...

 

[Condottiere]

If I had a spherical hull, I'd like to be able to adjust the diameter of the jump bubble.

 

[bookwyrm]

I don't have T5 so...

is there a price, size, power difference between the two types of jump drives?

personally, I could see the jump grid being used for any hull configuration and the jump bubble non- dispersed/close structured hulls.

for the jump grid, hull damage has a decent chance to damage the jump grid? (I've seen this mentioned in a few places)

and considering what has been mentioned about the jump bubble so far, how about a ship forcing another ship caught in the jump bubble to misjump, like a merchant ship forcing a pirate to misjump as a defense. silly, I know, but a jump bubble 5x the diameter of the ship it is on, centered on the jump drive... and what if the drive isn't placed in the 'center' of the ship? for larger ships, the bubble would be close to one end of the ship and further away from the other.

then there are the safe jump zones for the different sized ships equipped with jump bubbles. the bigger the ship, the further away from the planet, space port, other ships, anything else known to be in the area that you don't want to disappear in a jump bubble...

 

[infojunky]

This is why I keep going back to prolate/oblate spheroid hulls...

Every time this topic comes up round-ish trader designs keep popping up i my head. collections of pods around a jump drive and tanks with the bridge stuck on jus above the center of mass.

Then the Idea occurs Jump Drive Nodes that allow for longer hulls that look like the above but stretched out...