Jump Ships and LASH Boats

[ottarrus]

So, in light of @MasterGwydion 's thoughts on 'reverse tonnage jump drives', I thought I'd bring up another method of Alternate Jump Drives...

The idea is large capacity Jump mother ships with everyone else owning non-Jump capable boats of various sized. This is rather like the BattleRiders of Traveller, the JumpShip system of BattleTech, and several other sci-fi milieaux.
The Jump Ship would be a million ton vessel with lots of cargo space, some passenger room, and the ability to move a couple hundred thousand tons of boats of all types [military, commercial, private, whatever].

Now, normally I'd say that this would be most appropriate for smaller map sizes... say a quadrant of one sector in Traveller terms. But Battle Tech has made the concept work on a far greater scale that that. The Inner Sphere contains THOUSANDS of worlds. According to the website sarna.net the Inner Sphere contains 2 million stars and over 2000 colonized inhabited worlds. That's 6 or 7 Sectors in Traveller terms, assuming the average of 300 worlds per sector.

The advantages of this are fairly plain:
- Ships get their Jump fuel and Jump Drive tonnage back
- Planetary systems become more important as PCs have to spend more time in them
- It would make the polities a lot smaller

Thoughts?

 

[Arkathan]

Heighliners of Dune
With psionic navigators

 

[AndrewW]

Like the dreadnoughts in the Twilight Sector Traveller setting from Terra/Sol games.

 

[ottarrus]

Well, the Fifth Foreign Legion books by the Keith brothers have jump ships operated by a shackled A.I. instead of mutant psionic Dune fish...

I don't have the Twilight Sector stuff, so I can't say 'yea' or 'nay' to that.

 

[Sigtrygg]

Civilian jump frames have been a thing IMTU for a very long time now.

Many of them are directly subsidised by the Imperium and so can be called up during war time to rapidly transport military vessels.

 

[Condottiere]

 

[AnotherDilbert]

It's expensive...

Instead of one ship, you need several ships duplicating capabilities. Depending on edition it ends up more expensive, or much more expensive than monolithic ships.

There is no corresponding increase in income, so LASH systems tend to be less profitable.


Possibly express hi-jump passenger liners are an exception, e.g.:
https://forum.mongoosepublishing.com/threads/jump-train.118716/

 

[Sigtrygg]

A LASH tender can jump every 8 days, 43 jumps per year.

The expense is a jump engine not in jump space for half the year.

 

[AnotherDilbert]

A LASH tender can jump every 8 days, 43 jumps per year.

A scheduled freighter can jump every 9-10 days or so. Average time from jump point to the planet is just a few hours, even at 1 G.

A prerequisite for jumping the LASH tender immediately is having the payload modules waiting around, driving up the wasted time for the LASH system.

It's comparable time wastage.

 

[MasterGwydion]

A scheduled freighter can jump every 9-10 days or so. Average time from jump point to the planet is just a few hours, even at 1 G.

A prerequisite for jumping the LASH tender immediately is having the payload modules waiting around, driving up the wasted time for the LASH system.

It's comparable time wastage.

What if you combine LASH tenders with UNREP systems? That should cut the transfer times down to almost nothing.

 

[AnotherDilbert]

What if you combine LASH tenders with UNREP systems? That should cut the transfer times down to almost nothing.

Refuelling can be quick, e.g. with fuel pods and a breakaway hull. The payload pods can be exchanged quickly.

But:

CT LBB5'80, p17:
Because of the delicacy of jump drives, most ships perform maintenance operations on their drives after every jump. It is possible for a ship to make another jump almost immediately (within an hour) after returning to normal space, but standard procedures call for at least a 16 hour wait to allow cursory drive checks and some recharging.

I can't remember what, if anything, MgT2 has to say about that.

At a guess the 8 day jump cadence mentioned earlier is about as quick as it gets.

 

[Condottiere]

I believe GURPS also has cold fusion and fifty year endurance.

 

[Danestar]

Refuelling can be quick, e.g. with fuel pods and a breakaway hull. The payload pods can be exchanged quickly.

But:

I can't remember what, if anything, MgT2 has to say about that.

At a guess the 8 day jump cadence mentioned earlier is about as quick as it gets.

A brute force fix to this is for the ship to have 2 jump drives, you maintain the one not being used while in jump.

Problems begin when travellers start wondering what happens when you use the spare drive while in jump, something that resulted in several pages of notes and some rather scared players in one campaign I ran.

 

[Condottiere]

Assuming enough power and fuel, another jump bubble.

Which could lead to, double bubble trouble.

 

[Danestar]

That was the first thing they found, the second was allowing the ship to transit through the 100d area and use Lagrange points. There was other ideas but they wisely stopped experimenting.

Pity I never had them work out how to control things, every time they tried was the chance of making an extra long jump or far more likely to end in a different direction and far to close to something dangerous.

 

[tytalan]

A LASH tender can jump every 8 days, 43 jumps per year.

The expense is a jump engine not in jump space for half the year.

Not really between refueling connection the smaller vessels disconnecting the the current vessels plus travel time since jump is variable you can’t really have a pin point schedule. Plus maintenance your looking closer to a jump every 10 days with down time for maintenance every few months so more realistically 30 maybe at best 35 jumps a year. Not any better than a freetrader. Plus it’s not going to be economical feasible to jump to secondary or more remote systems often if at all. Figure 1 jump ship a week for most class A, once a moth for Bs, once a quarter for C and who knows for the rest.

 

[AnotherDilbert]

A brute force fix to this is for the ship to have 2 jump drives, you maintain the one not being used while in jump.

Sure, but that is a bit expensive: Not only are we duplicating the most expensive system onboard, the ship has to be larger to maintain the same payload, making everything more expensive.

 

[Danestar]

Sure, but that is a bit expensive: Not only are we duplicating the most expensive system onboard, the ship has to be larger to maintain the same payload, making everything more expensive.

I would agree, the only times I can see the benefit of having a second jump drive is when you really need to be able to jump as soon as your back in real space, your combining the 2 drives to give you the equivalent of a more advanced drive or the 2 drives are being used for some sort of jump shenanigans. As there has only been 1 official ship in traveller with 2 jump drives I would assume that most of the reasons you would need a second drive would be rare edge cases that would only occur in backwater subsectors.

On the use of LASH ships, GT Far Trader gives an estimate of the main ship being able to make an extra 4 jumps a year, with the best use for LASH ships being systems with multiple masked jump points.

 

[AnotherDilbert]

I would agree, the only times I can see the benefit of having a second jump drive is when you really need to be able to jump as soon as your back in real space, your combining the 2 drives to give you the equivalent of a more advanced drive or the 2 drives are being used for some sort of jump shenanigans. As there has only been 1 official ship in traveller with 2 jump drives I would assume that most of the reasons you would need a second drive would be rare edge cases that would only occur in backwater subsectors.

I can remember two published ships with dual jump drives, Leviathan and Annic Nova.

The general case is to have a backup drive in case of battle damage or on long expeditions away from any repair yard. Leviathan's secondary drives are explicitly backups.

TCS, p15:
SPARE SYSTEMS
Spare jump drives, maneuver drives, power plants, computers, and screens may be installed in a ship to take over in the event that the main unit is disabled. These are backup devices only and may not be in operation at the same time as the main device.

 

[Condottiere]

Current rules permit one plus chained together.

Limited by lowest common denominator.