Upgrading drives on exisiting ships

[Old School]

How do you approach drive upgrades in your games? I’m refereeing a Pirstes of Drinax campaign and my crew typically want to upgrade the m-drive performance of captured ships. Now they’re getting tired of Jump-2 limitations.

My ruling so far is that a jump drive is one system built for the task. So assuming there is a feasible way to add the capacity (using adjacent cargo bay space is the most likely), the entire existing drive has to be removed (can be sold, but limited demand for used jump drives) and a whole new j drive installed.

M drives I consider to be more modular. Extra capacity can be added so long as a reasonable reconfiguration of the deck plan can acommodate them. I dont have a formula for the additional retrofit costs, but I do make them material. M drives have to be in the rear of the ship. Not because that makes any sense, but because thats how all the existing deck plans do it.

 

[AnotherDilbert]

TCS (Trillion Credit Squadron) from MgT1 (or CT) has rules for refitting:

There are two different types of refit that can be used.

Major refits cover changes in power plant, manoeuvre or jump drive, as well as changes to spinal mounts or launch facilities (such as launch tubes). Removing these components costs 0.5 times the cost of the original system, while removing them and then installing new ones costs 1.5 times the cost of the new system. The time this takes is one quarter of the time required to build a new ship of the same size.

Minor refits are changes to any other components aboard the ship, such as weapon mounts or staterooms. Removing these components costs 0.1 times the cost of the original system, while removing them and then installing new ones costs 1.1 times the cost of the new system. The time this takes is one tenth of the time required to build a new ship of the same size.

Armour and other parts of the ship integral to the hull (such as configuration or reinforced structure) cannot be changed under any refit. Those items covered under a major refit cannot be increased in size though they may be reduced.

The last part marked in bold is harsh. It is probably based on the fixed Engineering spaces in LBB2.

I agree M-drives could be considered modular and just added to. Otherwise these rules are reasonable?

 

[Old School]

The 50% of cost to take something out, and for it to apparently have no value, is also harsh, but the rest makes sense. Thanks.

 

[WingedCat]

If you're increasing the drives - especially the Jump drive, embedded in the hull as it is (whether you're using jump bubble or jump grid) - you're kind of rebuilding the ship from scratch anyway.

 

[AnotherDilbert]

By CT, only a part of the jump drive is embedded in the hull. There is also conventional machinery. I don't think it's defined how big the parts are, and if the embedded part varies with jump performance.

None of this is described in MgT as far as I can remember.

 

[steve98052]

Perhaps a better approach to an overhaul that involves a replacement of the entire engineer section would be to transplant any crew sections that they've customized to the point that they'd miss it, and sell the ship that doesn't fit their needs.

 

[Geir]

Drive stuff: Add for m-drive, replace for j-drive. That all makes sense.

I'd give a trade-in salvage value for a perfectly functional old j-drive, though.

Power plant, there's already an example of an add-in extra power plant in one of the Great Rift adventures, so that looks like an obvious add-in like the m-drive.

Armor is the one that has me a little conflicted. It seems logical that any upgrade can't take more room than the original without a major hull redesign. Unless the entire hull had fuel directly behind it - then you could push some fuel into another compartment and modify inward. So if you upgraded from crystaliron to superdense, you could up the armor, but not the displacement.

But then High Guard p. 12 has this ambiguous sentence:
" A minimum TL is required for each type of armour, and there is a maximum
amount that can be attached to a hull – this includes any armour the ship had prior to modification."

Modification? It might only by referring to the case of planetoids, but I'm not sure.

 

[AnotherDilbert]

--- transplant any crew sections that they've customized to the point that they'd miss ...

Interesting idea, living quarters as module that just slides into the next ship...

I like it!

 

[AnotherDilbert]

Armor is the one that has me a little conflicted.

I think the idea is that the hull is a monocoque shell of armour (like Striker and MT). Adding armour would be replacing the hull with a thicker hull, and moving all other components to the new hull, basically building a new ship.

But then High Guard p. 12 has this ambiguous sentence:
" A minimum TL is required for each type of armour, and there is a maximum
amount that can be attached to a hull – this includes any armour the ship had prior to modification."
Modification? It might only by referring to the case of planetoids, but I'm not sure.

Yes, that refers to adding armour over the minimum while building the ship.

 

[Old School]

My rule is that items that are integral to the hull itself - armor, reflec, radiation shielding, etc. cannot be modified after construction. I could see arguments otherwise, but that’s how I do it.

 

[paltrysum]

Those items covered under a major refit cannot be increased in size though they may be reduced.

The last part marked in bold is harsh. It is probably based on the fixed Engineering spaces in LBB2.

I agree M-drives could be considered modular and just added to. Otherwise these rules are reasonable?

I'm glad this conversation came up. I agree that the bold part is a little harsh. That supposes that engineering bulkheads can't be knocked out and moved back to accommodate larger drives. I suppose they might be onto something if you suppose that an entire hull is really designed to be paired with certain drives and therefore upgrading the size of the engineering component isn't just a matter of adding a bigger, better drive system. It is potentially adding a bulkier, more powerful system that threatens to damage a hull that wasn't designed for it. If the idea is that the entire ship was designed to go along with the first set of drives, then yes, it makes sense to say you can't go bigger.

Personally, I'm going to disregard that. If they want to bore out, say, the accommodations section and put the starship equivalent of a V-12 in there, more power to them.

 

[AnotherDilbert]

That supposes that engineering bulkheads can't be knocked out and moved back to accommodate larger drives.

That is exactly what LBB2 says.

Personally, I'm going to disregard that. If they want to bore out, say, the accommodations section and put the starship equivalent of a V-12 in there, more power to them.

I would say everything can be done, but not everything can be done economically...

The refit rules describe what can be done reasonably economically. Changing things that the refit rules says can't be changed would cost more, probably much more.

 

[Old School]

Damn skippy. Besides, an engine that is overpowered as compared to its hull could be a useful plot hook if you so desire.

There are so many variations of deck plans, its hard to argue that you cant move walls to enlarge your engineering space,LBB2 be damned. Retrofit costs should be high, but it should also be doable.

 

[Condottiere]

1. I'd default to Trillion Credit in general.

2. Specifically, though, you could look at the deckplans and the ship configuration as to feasibility and cost of the refurbishment; originally, you had a set tonnage allocated to engineering.

3. If you couldn't alter armour plating factor, you couldn't repair the hull; but that would essentially be a house rule.

 

[steve98052]

One argument against fitting a more powerful maneuver drive into a ship is that it might exceed the limits of the acceleration compensation, which is a feature that extends throughout the full. So if you fit a 3 G drive into a ship built for 1 G, you might have all the ship's contents squashed at 2 G against this bulkhead or that, depending on the direction of maneuvers. That could be unpleasant, particularly if furniture is tumbling this way and that.

 

[Old School]

One of the handwavium technology features of traveller is that in normal conditions the occupants dont feel the G forces of high thrust drive due to the gravic plates throughout the ship, so I dont think there would be any extra stress on on fixturesor contents, either. Otherwise there would be no 6G acceleration to the 100 diameter jump limit. People cant take that kind of acceleration for that long.

As for armor, repairing and adding are very different considerations. Unless you are increasing the tonnage of the ship by bolting on addtional armor, you’d have to shrink the exisitng interior footprint all the way around to add additonal armor evenly.

I could see a ruling in which the ship isnt built to handle extra power (be it drives or power plant). And it doesnt make sense to make massive changes to. All three. But I think adding 1G of thrust, and a little extra power to handlethat drive and some additonal weapons ought to be doable, with some extra expense.

 

[Geir]

Traveller doesn't really go off and explain how gravity tech works. I already asked the question about the difference between m-drive and lifters and it seems like lifters are just built-in, like what levitates an air/raft.

So, let's say for your Cr 50,000 per dTon ship hull, you get lifters and compensators. That means regardless of a world's gravity you float - which is why a free trader can make it off a size 9 or A world. And inside, you get gravity compensation. Since the compensators are supposed to work from 0-2 gees (I don't know where that "fact" sticks from) then let's say the lifters work the same way - good for 2 gees gravity immunity. So lifters are good for gas giants smaller than Jupiter as well, making skimming without burning up or falling in possible around the majority of gas giants.

That leaves m-drive, also not deeply hand-waved. So let's say it creates a gravity "hole" for the ship - or more likely since the drives are in back, makes a "hill" behind you. So what happens if you fall off a hill or into a hole? You're accelerating all the way down, but you feel weightless. The only reason we "feel" weight on the surface of the Earth is because the stupid ground keeps us from falling further. It's not the fall that kills you…

So by the above convoluted logic, you should be able to add as much m-drive as you can fit or power to your ship. And you don't need to be particularly streamlined to land or take off from a size A world with a m-drive rating of 1.

 

[AnotherDilbert]

I already asked the question about the difference between m-drive and lifters and it seems like lifters are just built-in, like what levitates an air/raft.

Lifters are T5, they are not specified, nor excluded by MgT. Lifters were not included by default in CT&MT, but standard in TNE.

Lifters are anti-grav, like the air/raft, as you say. Anti-grav only works close to strong gravity sources like planets (MT, T5).

M-drives are anti-grav technology combined with damper technology (MT). According to T5 M-drives work relatively close to stars, but not in interstellar space.

So, let's say for your Cr 50,000 per dTon ship hull, you get lifters and compensators. That means regardless of a world's gravity you float - which is why a free trader can make it off a size 9 or A world.

You get compensators, MgT says nothing about lifters, leaving their existence up to you.

I don't use lifters, since I have generally not assumed lifters in earlier editions.

And inside, you get gravity compensation. Since the compensators are supposed to work from 0-2 gees (I don't know where that "fact" sticks from) then let's say the lifters work the same way - good for 2 gees gravity immunity.

Compensators are part of the M-drive, and completely compensates for the drive acceleration, according to CT&T5. Compensator effectiveness is the reason for TL limits on Thrust rating (CT,MT,&TNE).

By CT, the artificial gravity in ships is variable and can be set to 0 - 2 g or 0 - 3 g or so. That might be what you think of.

Lifters only just negate the weight of the ship, but does not make a effective drive, according to T5.

 

[Sigtrygg]

Acceleration compensation is a separate system to the m drive and the grav plates.

See CT Traders and Gunboats (and every other CT book that includes a detaild ship overview), MT ship design sequence and TNE FF&S design sequence.

Acceleration compensation has to mitigate extreme 'g' forces - a 6g m drive ship could be pulling 30+ 'g's as it manuvers during combat.

 

[Saladman]

I can see a case for having to to replace M-Drives in whole rather than part. They're already reactionless, and we don't have much information on how exactly they work. It would be just as valid to rule they're not linearly additive, or even that two adjacent reactionless drives could interfere with each other, as it would be to rule it's just like strapping on another rocket to a rocket ship.

Other than that I do take the approach that it can be done, with the addition that I would be looking at actual deck plans to get a configuration for the replacement J-drive, not only requiring some random allocation of space. So you could get a very odd deck plan after making the new drive fit in the old deck plan.