Ship Shapes

[Vormaerin]

Since this seems to be the week of funky space magic physics questions, I have one.

If Jump drives create a jump bubble in a sphere around them, which is how they are described when you aren't using a jump grid in the hull, then

1) Why aren't most ships spherical to maximize volume within the jump bubble?
2) Why are the jump drives in the stern of the ship instead of in the middle?

And if you have a jump grid, doesn't that make hull damage really really not okay with jumping? So Jump Grids would be contraindicated for warships? (especially if you use the T5 version where jump grids weaken hull armor and increase jump flash).

I know the reason I don't use spherical ships is because I'm not Ian Stead to draw badass ship art and deckplans for all the space balls I'd need. People don't draw spherical ships or 2300 style blocky with radiations ships very often...

 

[AnotherDilbert]

1) Why aren't most ships spherical to maximize volume within the jump bubble?

A jump bubble can't jump the entire volume. If you add a pod to a ship jump potential is diminished. Mass probably comes in here somewhere, but is simplified away for the sake of sanity.

T5.10, B2, p113:
D= (Tons * 13.5 )^1/3 *20 (in meters)
For example, a functioning jump drive in a 100 ton ship creates a jump bubble with a diameter (=100*13.5 ^1/3 * 20 = 11.05 *20 =) 220 meters.

The jump bubble is a lot larger than the ship volume it can jump...

2) Why are the jump drives in the stern of the ship instead of in the middle?

They can be anywhere you want. It's just customary to toss them into Engineering together with M-drives that are generally (but doesn't have to be) in the stern.

And if you have a jump grid, doesn't that make hull damage really really not okay with jumping?

More like "not quite ok". You should probably paper over the worst cracks with jump plates, before you presumably limp back to a shipyard for permanent repairs.

So Jump Grids would be contraindicated for warships? (especially if you use the T5 version where jump grids weaken hull armor and increase jump flash).

Yes, but more for armour and external pods, I believe.

I know the reason I don't use spherical ships is because I'm not Ian Stead to draw badass ship art and deckplans for all the space balls I'd need. People don't draw spherical ships or 2300 style blocky with radiations ships very often...

It's a pain to use a sphere for deck space effectively, especially for small ships. They are also not streamlined.

Large warships are often designed around a long spinal. Large commercial ships around a big square box of payload space.

Or more likely, force of habit...

 

[Condottiere]

1. Towing.

2. Jump nets.

 

[Alqualonde]

3. External Cargo Mounts.

 

[MasterGwydion]

A jump bubble can't jump the entire volume. If you add a pod to a ship jump potential is diminished. Mass probably comes in here somewhere, but is simplified away for the sake of sanity.

The jump bubble is a lot larger than the ship volume it can jump...



They can be anywhere you want. It's just customary to toss them into Engineering together with M-drives that are generally (but doesn't have to be) in the stern.



More like "not quite ok". You should probably paper over the worst cracks with jump plates, before you presumably limp back to a shipyard for permanent repairs.


Yes, but more for armour and external pods, I believe.



It's a pain to use a sphere for deck space effectively, especially for small ships. They are also not streamlined.

Large warships are often designed around a long spinal. Large commercial ships around a big square box of payload space.

Or more likely, force of habit...

Isn't the Tigress a spherical hull with a spinal mount?

 

[Vormaerin]

Sure, though one of the downsides listed for the jump bubble is that it extends beyond the ship and can pick up debris that screws your jump. This is also one of its advantages, as you can have a modular hull, external cargo/fuel attachments, etc. But if you have a 100m long needle ship with the jump drives at the aft, it presumably covers the entire ship in the bubble. So that means you've got an excessively long "tail" to accidentally clip other objects before jumping. A spherical ship with the j drive centrally located minimizes that hazard.

Of course, you could just say "sure, but you just check and its fine". But then it's kind of pointless to even mention as a risk factor.

I've never dived into T5's ship construction to really grok just how significant the armor penalty imposed by jump grids are, but its mechanically a thing. Similarly, it is not clear to me how much hull damage is necessary to disrupt the grid. It just says that it's a thing that happens and can't be fixed easily without degrading the system to function like jump plates. But it seems like military ships wouldn't use jump grids, especially if the "jump bubble can cause jump mishaps by grabbing debris" is not considered a real risk.

But I suppose it's irrelevant, since jump grids aren't used by any MgT2e ships that I recall. Just more design for aesthetics rather than how folks would actually do it. Just like the bridge being at the front of the ship, as if the pilot is looking out the window to steer while travelling at thousands of kph.

 

[Condottiere]

Tee/Five has three options, one that you can use for damage control for the lanthanum grid.

In theory, you could use a jump net to cover protruding parts of the hull.

Though more literally, you could cover the hull with in like camouflage netting, and dispense with the jump bubble.

 

[Vormaerin]

The Jump Plates are basically just the primitive, early version of the jump grid that now persists just for temporary patches.

And the jump grid is not made of lanthanum. The jump drive engine needs lanthanum for the coils.

 

[GypsyComet]

(There are several ways to arrange jump drive components *that have seen print* and are considered Canon for their particular editions. Lanthanum hull grid is one such, but not really for the Bubble version, which (generally) uses coils instead.)

A spherical ship intended to fill the bubble would take up more of volume, require a larger jump drive, and produce a larger bubble. Tuning the bubble back down makes it an accidental sheath drive, and then, yes, you would probably have to center the drive in the hull. If you don't push the diameter limit, you don't need to center the drive. Bubble drives are meant to be fault tolerant, so if you push the envelope, you push safety limits.

 

[AnotherDilbert]

Isn't the Tigress a spherical hull with a spinal mount?

Yes, it is. It is also a fair bit bigger than the other described types of battleships with the same spinal. You can make a ship with a spinal with any configuration, without any game mechanical difference, at least in CT and MT. There is still a background assumption that spinals are supposed to be long and slender, even if nothing forces you to draw deck plans that way.


By TNE FF&S, where such things are defined, the length of the spinal gun determines the range of the gun. Longer ship, longer gun, longer range.

There is also a max. range defined by the fire control equipment and to hit task, so it's no use making the spinal gun longer than necessary, even if that is quite long.

 

[AnotherDilbert]

But if you have a 100m long needle ship with the jump drives at the aft, it presumably covers the entire ship in the bubble. So that means you've got an excessively long "tail" to accidentally clip other objects before jumping. A spherical ship with the j drive centrally located minimizes that hazard.

Why? If a 100 Dt ship has a bubble that is a sphere of 220 m diameter around the jump drive, it's the same amount of waste space, regardless of hull configuration. It might be a bit more aft of the ship, less ahead, but still the same amount of space.

Whether the ship is a 37 m Suleiman or a 14 m sphere, they fit well within the 220 m bubble.

 

[Condottiere]

Default bubble size would probably be dependent on how much energy and/or hydrogen you pump into the jump drive.

 

[AnotherDilbert]

Of course, you could just say "sure, but you just check and its fine". But then it's kind of pointless to even mention as a risk factor.

It can be used as a post-hoc explanation if you actually misjump.

 

[AnotherDilbert]

Default bubble size would probably be dependent on how much energy and/or hydrogen you pump into the jump drive.

No, the only described variable is the size of the ship. Again:

T5.10, B2, p113:
D= (Tons * 13.5 )^1/3 *20 (in meters)
For example, a functioning jump drive in a 100 ton ship creates a jump bubble with a diameter (=100*13.5 ^1/3 * 20 = 11.05 *20 =) 220 meters.

 

[Condottiere]

I think this one Marc Miller got wrong.

 

[Vormaerin]

It can be used as a post-hoc explanation if you actually misjump.

So basically meaningless. Especially since you can't roll badly enough to misjump in CT or MgT2e without other more serious problems going on that would mean you don't need a retroactive explanation.

 

[AnotherDilbert]

So basically meaningless.

Yes, hasn't anyone told you that "T5 is a toolbox" yet?

 

[Vormaerin]

Well, having tools that don't actually do anything in your toolbox is kind of silly. All the "fluff" on jump grids has actual mechanics associated with it. As it is, jump bubbles are flat out superior for military ships. And probably superior for civilian ships unless you are really confident that a closer jump point is going to matter more than having more expensive repairs.

 

[AnotherDilbert]

Well, having tools that don't actually do anything in your toolbox is kind of silly.

No comment...

 

[RogerMc]

A wizard did it!

That is to say all FTL is magic and it does whatever the rules says it does.