Traveler core rules deck plans, first impressions

[bytedruid]

I'm new to standard Traveller, having just finished reading the core rulebook 2022. Most of the content is well ordered and reasonable (though some table entries have got to be typos), and the artwork is rather nice. Also, unlike BattleTech, the ships have deck plans (Whoo Hoo!)

Though, speaking of deck plans, only a few are reasonable. Good examples are the Laboratory Ship (p206), and Mercenary Cruiser (p216). Unfortunately, most of them have the following glaring safety flaw that would have been immediately corrected during early engineering design review:

• If grav-plating is off-line and the ship has to maneuver, all the long-axis hallways become plummeting death tunnels.

In general, when designing non-atmospheric spacecraft, down is always towards the reaction drive. Anything else is just silly. For ships that act as aircraft for some portion of their flight, rooms would still not be very long in the fore<-->aft axis because it's just not safe. Space travel is dangerous enough, futuristic ship designers wouldn't intentionally compound the problem with deck layouts such as these.

If anyone has a source of more reasonable standard designs, I'd be happy to pick it up.

(I'm assuming that maneuver drives are essentially reaction drives since they are described as generating thrust. As far a jump drives go, anything's fine. They're basically magic anyway.)

 

[Condottiere]

For the standard belly lander deck lay out, I would assume there are three forces prevailing during acceleration with a gravitic manoeuvre drive.

1. Deck artificial gravity, which is likely ninety degrees right angle to the nose of the spacecraft.

2. Felt acceleration, gravity multiplied by the (current) acceleration factor of the manoeuvre drive.

3. Neutralization of felt acceleration by the organic inertial compensation (field) of the manoeuvre drive.

4. Reactionary drive has no inertial compensation, and one assumes that that the naval architect would design the interior layout with that in mind.

 

[Reisender]

• If grav-plating is off-line and the ship has to maneuver, all the long-axis hallways become plummeting death tunnels.

If the brakes fail in a car at 100mph...

 

[MonsterX]

A plummeting death tunnel sounds like just the thing you'd want for discouraging a boarding party. Or passengers who complain about the food. Maybe even put in some punji sticks on the bottom wall. heh heh, heh heh, heh heh

You might want to put a big red warning sticker by the grav plate off button though, if you're the kind of whiney little baby that worries about stuff like this.

Does Traveller have an ISM code (International Management Code for the Safe Operation of Ships) or a SOLAS convention (Safety of Life AT SPACE - they'd have had to change the acronym to SOLIS)? Safety inspectors might have something to say about this.

 

[Lurking Grue]

if you're the kind of whiney little baby that worries about stuff like this.

Whoa, isn't that kind of harsh. It was a valid question and something I've wondered as well. As it is now, the artificial gravity and inertial dampening must be the most reliable and durable pieces of equipment onboard starships as if either of them breaks down or is damaged, most belly lander ships become, like the OP wrote, death traps (or you maneuver very carefully with minimal thrust, in the 0.1 G or less range). If the ships were designed with science and safety in mind, they would indeed be built as rockets (with the decks perpendicular to the main thrust direction), but instead they are designed with "ease of use" (can just walk off the ship) and "looking cool" in mind, so they are built like airplanes (or e.g. the Millennium Falcon). Also, many designs are from the original edition times and classic in many ways, so tampering with them would be equal to sacrilege.

So, I guess the answer to the OP is that the issue is practically hand-waved, not really taken into consideration. It's just how it is, roll with it. One could say it is assumed the tech is so rock solid that it practically never fails and is so distributed that a single hit cannot take it out completely and then leave it at that. Traveller is not hard SF, even if it tries to take science into consideration more than most sci-fi RPGs. It is space opera where the awe and wonder, in addition to "cool factor", measure as much, if not more, than scientific accuracy and such.

(Even so, I have long been tinkering with MTU, where ships are built as tail-landers, if capable of landing at all. Most use shuttles and dropships for planetary landings. But that's just IMTU.)

 

[NOLATrav]

If anyone has a source of more reasonable standard designs, I'd be happy to pick it up.

2300AD might be more to your liking.

It does sound like an interesting design exercise though: take a Free Trader hull and build it as a tailsitter. I guess ultimately you end up with ships that look like traditional rockets or maybe the Alliance patrol ships from Firefly.

The actions of Streamlined ships in planetary gravity wells would need more examination, I’d think.

 

[Vormaerin]

The inability of grav plates to fail catastrophically seems to be a pretty standard space opera trope. There are very few sci fi ships that are not built in this manner. Either the setting is rockets and tailsitters or the ships are built as if grav doesn't fail under acceleration.

 

[Condottiere]

The only real risk is if the inertial compensation (field) deactivates.

If artificial gravity gives out, everything floats.

 

[MonsterX]

Whoa, isn't that kind of harsh. It was a valid question and something I've wondered as well.

Sorry, I should have put a smiley face after it. Smiley faces have been added on edit. Of course it is a valid issue to raise, and an interesting topic to discuss.

 

[bytedruid]

We'll that generated a lively discussion Thanks for all the responses. I'll engage with them later after work.
Cheers,

 

[Geir]

So the thing with reactionless thrusters is that they might not actually produce a 'gravitational' acceleration effect. Consider freefall - you jump out of an airplane and you are falling at one gee (okay, not accounting for atmosphere but bear with me - let's say you jumped out of a lunar lander and are falling at one-sixth gee if you want to be pedantic). In orbit it's the same thing - except you're 'falling' around the world, moving fast enough to keep in a circular orbit.

So, if an M-drive distorts the gravitational field (okay warps spacetime, but this is all handwaving once the word reactionless gets thrown in) - if it makes a 'well' in front or a 'wave' in back, it is similar to freefall and all the interior grav plates are doing is providing artificial gravity inside the ship. If you are accelerating at 6G on that sort of M-drives and the internal gravity fails, you'd just be in freefall. Assume that is how M-drives work. Which is far from clear - just providing a scenario where it doesn't matter. I'm a big fan of tail sitter designs myself.

 

[Condottiere]

There are two reasons you will find that most commercial vessels don't use rockets, and do use gravitic drives:

1. Rockets use too much gas

2. Organic inertial compensation (field)

 

[AnotherDilbert]

Though, speaking of deck plans, only a few are reasonable.

Yes, depending on your definition of "reasonable". I tend to agree, possibly for other reasons.

• If grav-plating is off-line and the ship has to maneuver, all the long-axis hallways become plummeting death tunnels.

In general, when designing non-atmospheric spacecraft, down is always towards the reaction drive. Anything else is just silly.

The basic assumption is something like: The Imperium is thousands of years old, its tech base is thousands of years old. It's not experimental tech invented a few years or decades ago. Internal gravity doesn't just fail randomly. (If it does, just stop accelerating: problem solved.)

The real reason is that somewhere in the seventies people started to draw deck plans without worrying about the details too much, presumably inspired by movies and TV. Some of the first few deck plans were aircraft-like, and that stuck as the standard. And that predates any mention of artificial gravity in Traveller...


Of course tail-sitters makes more sense, but that didn't happen to become the default...

If anyone has a source of more reasonable standard designs, I'd be happy to pick it up.

You will struggle to find any collection as large or good as MgT core and Highguard. Just having deck plans for every ship is great! Individually they might not be perfect, but they are there and they are usable.

(I'm assuming that maneuver drives are essentially reaction drives since they are described as generating thrust.

Not really, it's a magical machine that turns power into thrust working on the drive.
An earlier edition said:

MegaTraveller, Referee's Manual, p56:
The second major breakthrough is artificial gravlty. Created by manipulating subatomic forces, artificial gravity is not anti-gravity but is instead a unique force that acts upon the natural gravity field created by all matter. Artificial gravity can be made to either push or pull [i.e. both artificial gravity and grav vehicles]. Because of its nature, artificial gravity is not a very efficient means of locomotion in deep space where there are no strong gravity wells to push against.

MegaTraveller, Referee's Manual, p56:
The fourth significant development came from the search for a starship maneuver drive that did not lose efficiency when away from a strong gravity well. Artificial gravity and damper technology led to yet another sub-atomic force-based technology. This new, artificially generated force pushes against a vessel's "thrust plates" themselves, which make true reactionless thrusters a reality for starship-sized vessels.

The idea is standard physics with some specified few exceptions, e.g. artificial gravity, manoeuvre drives, and jump drives.

My house cop out is that the manoeuvre drive acts on the local star system through the local gravity field, preserving Newton's Third, i.e. as the ship is accelerated, the local star system is imperceptibly accelerated in the opposite direction.

The contemporary Traveller bible, T5, says:

T5, B2, p101: "How Maneuver Works":
Elementary instruction systems explain:
Maneuver drives interact with gravity to move spaceships. Parts of the drive reach out and grab the gravity of a world or a star and push against it to make the ship move. Isn’t that neat?

T5, B2, p101: "How Maneuver Works":
M-Drive
Maneuver is the standard in-system ship drive. It interacts with gravity sources to produce vectored movement. It requires a separate Power Plant.
M-Drives are manufactured with performance levels from 1G to 9G.
M-Drives are subject to the 1000D limit: beyond 1000D from a gravity source, the drive operates at only about 1% efficiency.

As far a jump drives go, anything's fine. They're basically magic anyway.)

Agreed, but so are agrav and m-drives...

 

[Vormaerin]

If anyone has a source of more reasonable standard designs, I'd be happy to pick it up.

(I'm assuming that maneuver drives are essentially reaction drives since they are described as generating thrust. As far a jump drives go, anything's fine. They're basically magic anyway.)

As noted above, maneuver drives are magic reactionless drives. If you want starships that are built around a reaction drive, then you are looking at Ships of the Frontiers and the Aerospace Engineers Handbook for the 2300 setting. It uses a different FTL drive, but it uses reaction drives and spin based gravity so is more "realistic" to current technology.

 

[Condottiere]

You'd think that by now, research and development should have managed to recreate the inertial compensation (field) apart from a manoeuvre drive.

 

[Asimovian]

Hey @bytedruid, welcome to Traveller! I've been playing and messing with it on and off since about 1980, and I agree with your comments about deck arrangements. I think it would be interesting in a Traveller or other SF setting to use less fantastical assumptions about the viability and reliability of inertial dampening on spacecraft. Thinking along those lines, I designed a tail-sitting ship (attached) for a short-lived ALIEN RPG campaign I ran a couple of years ago. I enjoy having to consider design options constrained a little more by physics than what we tend to see in various space opera settings.

 

[Galadrion]

Late to the game here, but still...

I handwave this issue in my game by ruling that the inertial compensation is integral to the maneuver drive field effect, which would imply that as long as the drive is working (thrust is in effect), it is inherently being compensated, which means you don't have to worry about your inertial protection going *poof!*. If the compensation goes away, it's because the thrust has also gone away. No plummeting corridors of doom apply.

"But what about grav plates?" Those are there to provide a frame of reference. Without the grav plates, whether the M-drive is functioning or not, all contents of the hull are in a zero-g framework regarding that hull. The grav plates change that from zero-g to whatever gravity pseudo-field they're set for.

 

[NOLATrav]

I handwave this issue in my game by ruling that the inertial compensation is integral to the maneuver drive field effect

This is what I do as well. Your explanation is more thoughtful than I could have expressed.

I’m toying with making IC a bolt-on component for reaction drives, using T5 Lifters as inspiration.

 

[bytedruid]

Hey @bytedruid, welcome to Traveller! I've been playing and messing with it on and off since about 1980, and I agree with your comments about deck arrangements. I think it would be interesting in a Traveller or other SF setting to use less fantastical assumptions about the viability and reliability of inertial dampening on spacecraft. Thinking along those lines, I designed a tail-sitting ship (attached) for a short-lived ALIEN RPG campaign I ran a couple of years ago. I enjoy having to consider design options constrained a little more by physics than what we tend to see in various space opera settings.

Work's been crushing today, still at it so no time to respond properly, but WOW I have to tip my hat to this post! Nice work Asimovian! Well considered and well themed, it's practically art.

 

[GypsyComet]

The inability of grav plates to fail catastrophically seems to be a pretty standard space opera trope. There are very few sci fi ships that are not built in this manner. Either the setting is rockets and tailsitters or the ships are built as if grav doesn't fail under acceleration.

And the standard setting has had working gravitics of this sort for 10,000 years, originally developed by a people who make OSHA look like dangerous dynamite hurling freaks.