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Old 04-20-2022, 09:52 AM   #1
Pursuivant
 
Join Date: Apr 2005
Default Need Help on "Semi-Hard" Classic SF Spaceship Design

One of my back-burner projects is GURPSifying the Sector General books.

I've got a good handle on all aspects of the setting except for the spaceship designs.

My attempts to use GURPS Spaceships result in ships that are either way too big for what's described in the source material, don't have sufficient speed to match described performance, or have insufficient range or duration due to insufficient fuel tanks.

I'm assuming a Safetech/Retrotech TL9 setting for most TL, but the spaceship designs and "rubber SF" gear seem "happiest" at TL11^.

The books use a weird mix of hard and soft-boiled SF tech - reaction torch drives for sub-light and atmospheric maneuvering, "cold" reaction thrusters for low-speed space maneuvers, contragravity for low altitude atmospheric maneuvers, and hyperdrives for FTL travel. Fuel type for torch drives isn't specified but it exists.

Ships use torch drives or contragravity to take off from the planet and get into orbit, then use torch drives and constant acceleration to get sufficient speed and distance from nearby objects, and then jump into hyperspace. Sub-light speed and ship orientation is preserved in hyperspace but vector is not.

At the end of the trip the ship drops out of hyperspace, corrects course as needed, then decelerates until it reaches its destination. Landing is via some combination of wings, contragravity, and/or torch drives.

The "feel" of the ships is Golden Age SF: massive, heavily-built ships built using steel and light alloys, huge computers and communications arrays, and bullet- or dart-shaped aerodynamic lines.

Ship performance is comparable to anything from Star Trek or Star Wars. A fast ship can get from the habitable zone of a planet to its Oort cloud in just a few hours then jump to any place in the galaxy in less than a day.

Hyperspace performance is reminiscent of Traveller Jump Drives but power comes from a fusion powerplant, each leg of a hyperspace journey takes a day or less, and range is unlimited given accurate maps. Practically, this means you can jump to anyplace in the galaxy but the rest of the universe is terra incognito.

Four hours of constant burn is repeatedly described as the time needed to get away from the mammoth Sector General space station prior to safe hyperspace jump. There's the strong implication that a ship's speed when it enters hyperspace is a significant fraction of light speed.

Rescue ships are very fast - capable of getting to any place in the galaxy in a few hours - but can't remain on station for more than a week or so. During this time they can burn a lot of reaction mass with sublight maneuvers. Ship's crew is just 4 people, plus 3-4 medics or space salvage crew and space for 20+ sickbay patients in the equivalent of Automed beds.

Scout ships are capable of long-term, long-range galaxy survey operations while carrying a 4-person crew. They're lightly armed but reasonably tough and are capable of planetary landings using reaction drives. I assume they accelerate to a given speed and then coast along a set course, scanning everything as they go.

Warships are humongous, armed with missiles and tractor-pressor beams, and very tough to destroy. They can take smaller ships in tow using tractor beams, even taking them into hyperspace with them. They also have impressive contragravity which allows them to hover in a planetary atmosphere. In wartime they carry massive crews capable of boarding actions. In peacetime, they act as fast colony support and transport ships. Think battleships but with short- to medium-range medium-caliber guns.

Common ship design features are: Aerodynamic Lines, Steel or Light Alloy Armor, Contragravity, Giant Computers and Electronics Arrays, limited Force Fields (only deflect physical objects not energy), Fusion Powerplants, Hyperdrives, Tractor Beams, "Hot" Torch Drives, and "Cold" Low-Speed Maneuvering Thrusters.

I've modified the standard Fusion Torch drive so it gives 5G acceleration and 150 mps delta-V. Sensor Array ratings are reduced by 1 to reflect increased bulk.

Weapon stats are nerfed to make space combat into short-ranged maneuver-based slugging matches and to encourage boarding actions.
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Old 04-20-2022, 11:37 AM   #2
Fred Brackin
 
Join Date: Aug 2007
Default Re: Need Help on "Semi-Hard" Classic SF Spaceship Design

Okay, I've read all of these but not lately.

Reaction drives? That's not the idea I got. I always assumed no fuss/no muss Reactionless. Those "fuel" limits are more likely ased on the old misusndertanding about how fast nuclear power plants burn fuel i.e. on a scale of years and not days.

Very specifically, there are no felt G-forces. If the super-low G insectiod Dr Prilicla can go on ambulance calls there's nothing a human would even feel. Pricla's personal G-field device would seem to have a whole ship version.

The heavy beam weapons of the big ships appear to be Force Beams from UT. Those didn't make to spaceships officially but ISTR once calcluating them to be dDam2 and R2 but with no Armor divisor. This should match the stats for TL10 Lasers and Force beams in UT.

Obviously there's at least some sort of FTL comms. Specificaly the low information "distrtess signals" the ambulance ships respond to.
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Old 04-20-2022, 11:56 AM   #3
Anthony
 
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Default Re: Need Help on "Semi-Hard" Classic SF Spaceship Design

The base problem for talking about what kind of ships Sector General had is that ships in Sector General are basically scenery; the novels were not about what the ships can do.
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Old 04-20-2022, 01:14 PM   #4
johndallman
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Default Re: Need Help on "Semi-Hard" Classic SF Spaceship Design

Quote:
Originally Posted by Anthony View Post
The base problem for talking about what kind of ships Sector General had is that ships in Sector General are basically scenery; the novels were not about what the ships can do.
Absolutely. Jim's fans talked to him about the medical twists in the plots, not the ships or logistics. Also, it seems unlikely that all the cultures in the galaxy use the same ship technology.

Last edited by johndallman; 04-21-2022 at 01:38 AM. Reason: Spelling
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Old 04-20-2022, 01:38 PM   #5
Rolando
 
Join Date: Feb 2005
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Default Re: Need Help on "Semi-Hard" Classic SF Spaceship Design

The best solution is to decide by fiat what ships can do, use the lore you have to determine how they work and how they perform and that's it.

Even if players end using those ships in ways the original author never intended you just make it up as you go, as long as you stay consistent withing the parameters you defined that emulate the original setting you will be great.

The spaceships book is great if you are using it to create new things or adapt easily adaptable setting, when things start to feel very different to the GURPS systems, specially if these things (spaceships) are not the main focus of the game/campaign, you will be better not using strict Spaceship construction. Use the rules and things that make sense and discard the rest.
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Old 04-21-2022, 05:02 AM   #6
Pursuivant
 
Join Date: Apr 2005
Default Re: Need Help on "Semi-Hard" Classic SF Spaceship Design

Quote:
Originally Posted by Anthony View Post
The base problem for talking about what kind of ships Sector General had is that ships in Sector General are basically scenery; the novels were not about what the ships can do.
Trust me, I know. I've closely read all the books to do this adaptation.

I was just wondering if there as a way to square the circle wrt GURPS Spaceships.
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Old 04-21-2022, 05:14 AM   #7
Pursuivant
 
Join Date: Apr 2005
Default Re: Need Help on "Semi-Hard" Classic SF Spaceship Design

Quote:
Originally Posted by Fred Brackin View Post
Reaction drives? That's not the idea I got. I always assumed no fuss/no muss Reactionless. Those "fuel" limits are more likely ased on the old misusndertanding about how fast nuclear power plants burn fuel i.e. on a scale of years and not days.
Functionally, I might have to go with reactionless drives, despite the fact that there are plenty of passages in the books about thermal and other effects from drives and all sublight spaceship maneuvers follow Newtonian physics.

Quote:
Originally Posted by Fred Brackin View Post
Very specifically, there are no felt G-forces. If the super-low G insectiod Dr Prilicla can go on ambulance calls there's nothing a human would even feel. Pricla's personal G-field device would seem to have a whole ship version.
I've assumed gravitic compensators for all ships. Felt G-forces exist, but they are low. Prilicla and members of other extremely low-G species operating in 1-G wear two personal Antigravity belts/gravitic compensators in addition to anything built into the ship.

Quote:
Originally Posted by Fred Brackin View Post
The heavy beam weapons of the big ships appear to be Force Beams from UT. Those didn't make to spaceships officially but ISTR once calcluating them to be dDam2 and R2 but with no Armor divisor. This should match the stats for TL10 Lasers and Force beams in UT.
Functionally, this might be the best way to go, but they're specifically described as being tractor-pressor beams in the books and can be used at lower settings for peaceful purposes.


Quote:
Originally Posted by Fred Brackin View Post
Obviously there's at least some sort of FTL comms. Specificaly the low information "distrtess signals" the ambulance ships respond to.
I've got this one well in hand. FTL radio has penalties beyond a given range, with increased penalties for smaller radios in addition to their inherently shorter range. Modifiers for Time Spent give a bonus, based on resending the message over hours or days.

Distress beacons are standard shipboard equipment and give massive bonuses to be detected as long as they last.
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Old 04-21-2022, 05:34 AM   #8
sir_pudding
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Default Re: Need Help on "Semi-Hard" Classic SF Spaceship Design

You could use hot reactionless drives. They could also consume fuel, just not nearly as much as would account for reaction mass.

These assumptions are generally true for a lot of sf. Presumably because the authors felt that ship drives should have destructive plumes or wash and that ships should consume fuel, but didn't do any math.
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Old 04-21-2022, 05:51 AM   #9
Pursuivant
 
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Default Re: Need Help on "Semi-Hard" Classic SF Spaceship Design

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Originally Posted by sir_pudding View Post
You could use hot reactionless drives. They could also consume fuel, just not nearly as much as would account for reaction mass.
This the way to go, either that or assuming super-efficient fuel which takes up far less space and provides far more delta-v than in GURPS Spaceships.

My main problems are that per GURPS Spaceships the smaller ships don't have the speed or endurance to do what they are described as doing in the books. Big ships aren't as much of a problem.

I will go with reactionless drives with a single fuel tank as homage to the idea that they use reaction mass.

I've got the ambulance ship Rhabwar statted out. It works pretty well using the Spaceship rules with some tweaks. I've also created some of the more unusual Federation ships as potential "victims" and allies.

Quote:
Originally Posted by sir_pudding View Post
These assumptions are generally true for a lot of sf. Presumably because the authors felt that ship drives should have destructive plumes or wash and that ships should consume fuel, but didn't do any math.
This. James White had some very cool ideas, but no scientific background. It's also obvious that he didn't keep notes on the universe and characters he created so there's lack of continuity from book to book.

If there's interest in a fan-based SG GURPS supplement, I can create a dedicated thread for it.
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Old 04-21-2022, 08:07 AM   #10
Varyon
 
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Default Re: Need Help on "Semi-Hard" Classic SF Spaceship Design

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Originally Posted by johndallman View Post
Also, it seems unlikely that all the cultures in the galaxy use the same ship technology.
Depends on the setting. Deathworlders gave a pretty decent initial explanation of why, prior to humans getting involved, basically all the alien species largely used the same technology - they became members of galactic society once they figured out FTL travel, and it was generally easier to just adopt the (more advanced) technology used by the rest of the galaxy than continuing to develop their own. Humans, having evolved on Earth (arguably the most hostile life-producing planet in the galaxy), had a lot of crazy ideas that shook things up, of course (but even they initially relied on the tried-and-true, already-established technologies, although they divorced themselves from that reliance as quickly as possible). And it turned out that the technological homogeneity was largely due to a vast, ancient conspiracy suppressing certain developments, but I digress...

Quote:
Originally Posted by Pursuivant View Post
Functionally, I might have to go with reactionless drives, despite the fact that there are plenty of passages in the books about thermal and other effects from drives and all sublight spaceship maneuvers follow Newtonian physics.
I like to call this "semi-reactionless" - the drives use reaction mass, have drive plumes, etc, but they get physically-impossible efficiency out of it, and typically their drive plumes are far less energetic - and have far less range, such that an orbiting ship could just turn to have the planet it's orbiting directly behind it and go full-throttle without any ill effects on said planet - than they should be.

As for matching the performance of the ships in the source series (which I haven't read any of, nor indeed do I have any familiarity with), I'd suggest looking at a few of the ships you consider iconic (that is, those that your players will protest if they have markedly different performance than seen in the books) and base the behavior of your drives off of that. This may mean everything using the same drive technology but its efficiency goes either up or down as ship size (and thus the size of the drive itself) increases, or it may mean different technologies used in different applications (which again could be a size issue - maybe the drives used for smaller ships simply don't work on larger ones).

And if I wasn't being clear - absolutely, you should just create your own drives if nothing in Spaceships matches the performance you need.
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