FTL rate of movement for GURPS SPACESHIPS
 

Hello Folks,
In digging up some of my older material from FULL THRUST, and jogged by a memory elsewhere in this forum, I thought I'd bring up the idea of making smaller ships move more quickly via FTL than larger ships.

In a nutshell, the rate a ship travels is equal to its mass^.2 such that a 1000 ton ship would 3.98 days to travel 1 light year. A 1,000,000 ton ship would take 15.85 days per light year to travel.

It is an easy enough formula to utilize - but you can always customize it to some extent. For instance, if you want a 1,000 ton hull to be able to travel at about 1 light year per day, you could simply make the formula as being .25 * Mass^.2.

Thus, smaller ships can fast without needing to do much to change how the game works when designing ships in general.

If you really want to have fun? Make it simply that the ship moves at a rate of Mass^.20 days per light year PER FTL engine. Thus, with two such engines, you halve the time required to travel 1 light year.

If you don't like the fifth root of mass, then use some other value such as cube root or log of, etc.

Just a way to maybe fiddle with the formula to make things work in a manner that might be more fun. Maybe.

Re: FTL rate of movement for GURPS SPACESHIPS
 

Is there any particular reason to want small ships to move between systems aster than large ones?

Re: FTL rate of movement for GURPS SPACESHIPS
 

Is it so that small, unmanned message torpedoes can carry communications and other information far faster than people can travel? Is it so that transport will be divided among a myriad of small ships so that there is always a number of starships in any system and rarely only one to deal with an unexpected event?

Re: FTL rate of movement for GURPS SPACESHIPS
 

When I was handling FULL TRUST campaigns back in the day when it was JUST the original FULL THRUST rules - there wasn't all too much to difference the smaller ships from the larger ones. The "mass rules" were different for that game, but I recall working on that problem so as to give a reason for having "Scouts" that were smaller. They could get to a trouble spot faster, scout things out and possibly even return. The larger ships, taking longer to arrive, were massive firepower platforms, but if they took longer to arrive - it allowed for smaller ships of a destroyer class or corvette class or what have you, to engage in smaller ship actions.

Is it worth it to have for use with GURPS SPACESHIPS? Can't say, it would be up to the GM or player to suggest to a GM "Hey, what are the implications of this".

In the end? It is an idea being tossed out there for any who might like it enough to try it. If even one person gives it a shot, or it gives someone an idea on how to customize their own FTL ratings for their games, I can rest happy that a few electrons died for this.

;)

Seriously though. What WOULD be the implications?

As was pointed out, it would allow for smaller ships to make good couriers. It would also perhaps allow for smaller ships to be able to outrun the larger ships?

Suppose you had a 300 ton hull flee a star system with a 1,000 ton hull in hot pursuit. Let's say that they're both trying to reach a destination that is 3 light years away. The 300 ton hull will take 9.38 days to reach its destination. The 1,000 ton hull will take 11.94 days to reach its destination.

That makes a difference no? If the ability to have FTL-2 makes it such that you halve the time taken, if both have FTL-2, the smaller ship STILL retains an advantage.

Now suppose we're dealing with a game universe where the GM uses reaction drives, or solar sails or what have you, no "reactionless" drives at all? What if the "FTL limit of a star is based on solar masses and the limit was 2 AUs x Solor Masses?

Now we have something Traveller-like in that ships can approach up to a give point, but then have to rely upon good old fashioned newtonian movement.

For every ship system that is given up for FLT drives, the ship's fighting capabilities become weakened. But take a hard look at what happens when dealing with a Dreadnaught class ship at say, 30 million tons.It would take 93.88 days per light year of travel. Even with FTL-5, that Dreadnaught will take 18.77 days to arrive. Compare this with the 300 ton hull taking only 9.39 days to travel the same distance.

In the end, it is an easy way to handicap the larger ships in speed where FTL is concerned. Some might not like that idea (many probably won't). That is, until they need to be on a FAST ship. Fast and Fragile, or Slow and sledgehammers? <shrug>

Re: FTL rate of movement for GURPS SPACESHIPS
 

It will certainly encourage the use of message torpedoes/probes. If you use Spaceships there's already incentive to use many small ships over few large ones, even for civilian use - the cost per ton is the same, the payload per ton is the same, and the 'small ship fleet' is more flexible. For military purposes, the small ships are even more strongly selected for - missiles make ships eggshells with hammers, so you want each egg to be as cheap as possible.

The proposed FTL system hammers this home, even with a relatively slow loss of speed with increasing mass.

It would likely kill carrier+fighter and carrier+rider concepts, because the big carrier would be strategically slow compared to a fleet of small ships.

It would make small PC-owned ships faster than the lumbering great warships of the Evil Empire. However, if two FTL drives means you go twice as fast, a 30,000 ton ship with two drives is very nearly as fast as a 1,000 ton ship with just one, which might not be a strong enough speed difference to really differentiate ships by speed.

Re: FTL rate of movement for GURPS SPACESHIPS
 

I generally have FTL drives give more speed when you have more of them and/or put more power into them (assuming they're designed for that - or even if they're not if you're willing to risk Bad Things happening). My current rule is: [Power Points used by Stardrives]^0.5 x 5 lightyears/day (round to the nearest whole number), and you can have any mix of Stardrives and Super Stardrives, but they have to all be in the same hull section. Thus the most speed you can get is with seven Super Stardrives, consuming 14 power points, for 19 LY/day (and as at TL10-11 it takes four power plant systems to power these drives, 55% of the ship is just FTL drive and power for it). Most ships just have drives good for one or two points, and thus 5-7 LY/day.

I think most fast ships will tend to be relatively small, because most of the time you don't need to move massive amounts of stuff very fast at considerable expense. There will be some fast larger ships, of course - the rich might well pay for faster travel, the military will probably like some decent sized ships capable of fast interventions, etc., but most big ships won't, IMO, be especially fast.

Re: FTL rate of movement for GURPS SPACESHIPS
 

Assuming that you include the defense favouring switches then it creates the early 20th century paradigm of battleships for heavy firepower, destroyers for speed and cruisers to catch destroyers.

Re: FTL rate of movement for GURPS SPACESHIPS
 

On the other hand, the larger ships don't need engine rooms and can be automated more cheaply. I recently did a cost study for a particular set of assumptions, and found that a highly-automated SM+12 ship came in 30% cheaper per ton-lightyear than an SM+9 ship with an engine room.

Re: FTL rate of movement for GURPS SPACESHIPS
 

I disagree. Modern day carriers are lumbering hulks compared to jet planes. However, modern day carriers are not meant to be front line vessels, they are meant to serve as a base of operation for the much faster fighters, a place where the pilots can take their fighters to rest, refuel, rearm, and repair.

I see nothing about the proposed setup that would change that, though it does open the door for a different class of medium-occupancy "corsair" fighter which has limited fuel, repair/maintenance capabilities, and extremely cramped living space but is based out of a carrier allowing the crew to rotate and any necessary repair/maintenance to be done back on board the carrier. These would be larger than your typical fighter, capable of operating on their own for a few weeks, but smaller than your typical independent ship. Given the background description such vessels could dart around ahead of the larger fleet, performing reconnaissance or hit-and-run operations.

Re: FTL rate of movement for GURPS SPACESHIPS
 

What would happen if you flipped the assumption? For example, that spacecraft possessed a speed equal to ((mass^0.5) × (FTL engines^0.5))c? In that case, a 100 metric ton smallcraft with four FTL engines would have a maximum velocity of 20c while a 10 million metric ton capital ship with one FTL engine would have a maximum velocity of 3,160c. It would give a military reason for large ships and a logical reason for carrers.

Re: FTL rate of movement for GURPS SPACESHIPS
 

A modern carrier is as frontline as any ship in a carrier group. Either the whole group is out of reach of the enemy, or it is not.
The OP is proposing an FTL system that makes large ships noticeably slower in FTL than small ships. Thus a carrier with a fighter wing is slower strategically than a fleet of FTL gunships. As missiles tend to make large ships a liability anyway, it works against carriers quite strongly, because they have to carry the fighters right into any system there's combat in (and may have to recover them directly from combat). A gunship fleet's support vessels, if they're operating very far from a base, may be no faster than a carrier, but they don't have to come into a hostile system - they can be non-combat vessels in a way that a carrier can't.

Re: FTL rate of movement for GURPS SPACESHIPS
 

Bulk freighters dominate interstellar shipping and small tramp cargo vessels don't exist except in really marginal areas that simply don't have the volume of trade to fill large vessels, even when you run the large vessels in a long circuit to give the cargo plenty of time to pile up. The small vessels not only can't carry much, they do slow slowly.

For long distances you'll have your small FTL scout or yacht carried by a larger vessel, and if this is at all common it'll be a standard procedure.

Re: FTL rate of movement for GURPS SPACESHIPS
 

While these classes had differing tactical speeds, where their strategic speed varied it did in ways you might not expect - for long distance movement destroyers were often quite slow because they were small (making them uneconomical at quite quickly as their speed rose, and they lost speed in bad weather) and carried little fuel (so they had to travel slowly to conserve fuel if they were moving long distances between bases). Cruisers were only faster than battleships if they had reasonably close bases for the same reason. However, these things varied a lot depending on the exact time - before reduction gearing was used the only steam turbine ships with good range were ones with 'cruising' turbines, and that limited them all to quite slow cruising speeds.

Also, if you're using that naval model, destroyers are fleet boats and FTL that's faster than that of the battleships is wasted, as they'll be moving as a group. Cruisers are the scouts and would need fast FTL speeds, but destroyers wouldn't.

Re: FTL rate of movement for GURPS SPACESHIPS
 

I assume that's including crew salaries and life support costs, etc. Did you try a SM9- ship with Total Automation of the Engine Room?

I'm curious as to whether the high cost of total automation would be worthwhile in this case.

Re: FTL rate of movement for GURPS SPACESHIPS
 

I suspect you get better results if you cap the speed gain from size at some point. That sort of thing happens all the time, as different limiting factors take over.



If you want to create a fighter and carrier paradigm, increasing the FTL speed of the fighters is a little odd, unless you intend for battles to be fought with carriers parked in different systems sending fighters back and forth to each other. Also, with many paradigms you end up with the "Carriers" being nothing more than fuel tankers and cargo ships, so watch out for that.

Re: FTL rate of movement for GURPS SPACESHIPS
 

You'd get the Alternity Star*Drive setting.

The purpose there was to isolate small PC ships in a frontier sub-setting. The mostly barren area between the Core and the frontier (or whatever it was called) would have been more than year's trip for PC ships and they couldn't carry enough food and would have broken down without their yearly maintenance. Gigantic ships could jump 10x as far per week and thus link the Core and the Frontier together.

It worked to produce the isolation that TSR wanted but put a pretty sharp damper on PC importance generally. Want to warn your homeworld that the Evil Corporate Cruiser is coming? You can't get there before it does.

Re: FTL rate of movement for GURPS SPACESHIPS
 

Yes, and propellant, insurance, amortisation, depreciation. Also maintenance, repairs, and overhauls of the reaction and FTL engines based on engine hours.

No. It seemed to me that total automation is so expensive that you would need really, really low interest rates, insurance rates, and depreciation to let it compete with crew salaries, quarters, and life support.

At 8% interest, insurance, & depreciation (which was as low as I dared to go) each workspace totally automated costs G$400,000 per year. Spaceships 2 suggests a crew employment cost of $67,200 per year for base-level crew, plus which it costs G$150,000 (G$12,000 per year) to give them a cabin, $75,000 to give them a shared stateroom or couchette, or $37,500 a bunk in a bunkroom. And $730 per year for consumables. High automation is really marginal at 8%, even with comfortable long-occupancy crew quarters. Only adding foremen to large crews puts it firmly over the top.

If I had ships with very small payload fractions it might be different: total automation of all workspaces and NAI "officers" might mean having no crew habitat at all. But I was at a payload mass fraction of 70% or better, so it obviously wasn't going to work.

I'll take a look after breakfast and get back to you.

Re: FTL rate of movement for GURPS SPACESHIPS
 

I would expect a couple of interesting results:

1: Carriers would become a real big deal.

2: Ships would have some kind of connection device or coupling connection.

For some applications, staying together is much more important than speed. You don't want your big ship to jump in-system with no support, so attach a few (dozen) small ships to it's hull and have them ready to detach. This is not necessarily a military application, but for an exploratory mission, everybody may want to arrive together and not 3 days ahead of the supply cruiser.

Similarly, having all the ships show up at the same time may be better than being fast. Even with an exponential slow-down, having all 30 invading ships show up at the SAME time instead of over the 5-minute span which is the closest you can get with careful weighing may be worth a full 2-day delay in the plans. Even with careful weighing and math, it may be impossible to time things better than a few hours when systems are days apart. And that can be an eternity in battles.

If these connections double as some kind of emergency towing and/or rescue attachment and are standardized, that's a bonus.

Re: FTL rate of movement for GURPS SPACESHIPS
 

My small freighter cost G$207,307.69 per "compartment" of cargo space, and the large freighter G$189,233.33 per "compartment"; the passenger ships cost G$368.846.15 per passenger compartment and G$358,677.78 per passenger compartment. So total automation is more expensive than more/bigger ships as a way of increasing payload, in the situation I modelled.

Re: FTL rate of movement for GURPS SPACESHIPS
 

And in which even 30-ton "fighters" take a couple of days to travel one light-year and a month or so to travel the typical distance between a habitable planet and its nearest neighbour among habitable planets.

Re: FTL rate of movement for GURPS SPACESHIPS
 

Which is rather slow. Slower universal FTL speeds usually mean that larger ships are more effective and efficient, as they are capable of doing more stuff, but a difference in FTL speeds that favors smaller ships changes generally messes everything up. When it gets that slow though, it really means for combat is that interstellar wars will be fought with waves of automated SM+4 fighters equipped with missiles with antimatter warheads.

Re: FTL rate of movement for GURPS SPACESHIPS
 

For easier math, you can get something similar by saying a ship takes its dST in hours to travel one lightyear (or parsec, or 10 ly, or whatever). That 1000-ton ship (dST 70) would take 70 hours (2.9 days) per lightyear, while a 1,000,000-ton ship (dST 700) would require 29 days per lightyear.

Re: FTL rate of movement for GURPS SPACESHIPS
 

I had a feeling it probably wouldn't be worthwhile. I do wonder how removing the engine room entirely changes things - it reduces crew requirements, and frees up space for more payload. The question is how much the -1 HT and the annoyance of having to do maintenance from outside the ship costs compared to the savings, and I have no idea how best to assess that.

Re: FTL rate of movement for GURPS SPACESHIPS
 

You would need to make assumptions about the amount of extra hangar time needed for the maintenance and the increased rate of depreciation. I'd start with the number of staff-hours that the crew in the workstations put in for the amount of extra MRO, and I might start on the costs of lower HT by looking at the rules for extra maintenance costs of Cheap and Used Ships at the top of Spaceship 2 p.28. You could interpret -2 to HT as costing 1% per month in extra maintenance, and -4 to HT as costing 4% per month in extra maintenance, extrapolate a value for -1, and apply it only to the price of systems that would have a workstation requirement if the ship were large.

Re: FTL rate of movement for GURPS SPACESHIPS
 

I notice that Cargo Holds, even refrigerated ones, do not require any workstations, and thus a ship that is largely cargo spaces will have little increased maintenance with your suggestion. I think both this effect and your suggestion make sense.

As for the OP's thought on making smaller ships faster, how about simply having a cap on speed that varies depending on ship size? If each stardrive/super stardrive produces 5LY per day for each point of power, and the maximum FTL speed is set at something like: 80 - (SM x 5) LY/day, then a SM+6 ship (a little 100 ton scout, FTL shuttle, or heavy fighter) can do a maximum of 50LY/day, and so can't utilise the output of more than five Super Stardrives. A SM+13 ship (a 300,000 ton freighter or major warship, say) can do no better than 15LY/day, and shouldn't mount more than three standard Stardrives or one Super and one standard Stardrive.

This means that for the same speed a large ship is no less mass efficient than a small one, they just can't go as fast.

Re: FTL rate of movement for GURPS SPACESHIPS
 

While it lends itself to certain types of adventures, a faster FTL speed for smaller spacecraft distorts everything. Why have capital ships when you can use the same tonnage in automated bombers to accomplish the same military goals faster? Why have merchant haulers when you when you can use the same tonnage in automated cargo pods to accomplish the same commercial goals?

By having smaller spacecraft go faster, you remove any economic or military reasons for humans to be in space. Now, if your group wants to play AIs, that is fine, but I think that would get boring after a while, as there would be no particular reason to allow robotic bodies on the drone. After all, a robotic body would count against the cargo/weapons available to the drone...

Re: FTL rate of movement for GURPS SPACESHIPS
 

Umm. Why do you assume automation is related to size? Why would robots/AIs not invalidate humans on large ships just as well as small?

Actually, it's easier to do this on large ships, because of the automation rules.

Re: FTL rate of movement for GURPS SPACESHIPS
 

Automation is not mandatory on capital ships. When it comes to long distance SM+4 or SM+5 spacecraft though, automation is mandatory because they cannot have habitats. In addition, smaller spacecraft only need to pay for automation if they have an Engine Room. If their designers are willing to accept a -1 HT (after all, who cares in the case of a drone), they do not need to pay for automation.

Since you automatically have automation for long distance SM+4 spacecraft and since SM+4 spacecraft are the fastest spacecraf in this scenario, conflicts end up being decided by whom can send the most antimatter warhead equipped drones against the other side. It would not be unreasonable for a TL10 developed planet to be capable of fielding multiple wings of ten thousand such drones, which would mean 250,000 16cm missiles with 25 kiloton antimatter warheads of each. Since they would travel faster than larger spacecraft, such a world could torch the worlds of their enemies and have their drones return for resupply long before the capital ships of their enemies reached their systems.

Re: FTL rate of movement for GURPS SPACESHIPS
 

In light of automated drones being the ultimate system, might it not be best to limit FTL capabilities to hulls of a given size?

Some of the issue being discussed in the previous post apply to autonomous units regardless of whether one uses a uniform speed for FTL travel or not. One could use the same "wave" tactic using automated drones regardless. If, as in Traveller, FTL is limited to size modifier +7 or +8 hulls, that might help (not really in my opinion).

In the end, it seems to be an issue where GURPS ULTRATECH plus assumptions about SAIs etc, make human crewing illogical and inefficient. My suggestion is to revisit the assumptions inherent in artificial intelligences. But, that is a topic for another thread - one that will likely have some major ramifications not only on an adventuring level, but also cultural level. If AI labor is superior than flesh labor, then AI labor will supplant human labor, interfering with a human's ability to compete in the current economic model of exchanging labor (time) for finished goods/services produced more cheaply elsewhere via robotics coupled with computers.

In the end? The suggested route of autonomous robotic fighting spacecraft will result in BERSERKER style stories (see Fred Saberhagen). From there, it makes more sense to have robotic tanks, or robotic soldiers.
Your miles may vary.

Re: FTL rate of movement for GURPS SPACESHIPS
 

If you're looking to chnge the balance of combat you want to diddle with non-ftl propulsion.

For example if you have sub-warp drives but limit those to SM+4 hulls you have no super-missiles. You could have SM+4 robo-kamikazes but those would be orders of magnitudes more expensive to do massive strikes with.

Small ships would have to fight other small ships with beam weapons and armoring big ships so small ship beams can't damage them requires only that you edit out those beams with the highest armor divisors.

Re: FTL rate of movement for GURPS SPACESHIPS
 

Automation doesn't have a lot to do with size, you can automate SM+10 craft just as easily as SM+4, but an easy way to avoid that sort of distortion is to place a limit on the number of drives large ships can have, so small ships can be faster (by having more drives relative to their size) but aren't more efficient.

Re: FTL rate of movement for GURPS SPACESHIPS
 

No, you do not automatically have automation. What you have is minimal to no maintenance being done, which may or may not matter.

Nor, by the way, are they much faster than the enemy's slightly larger gunships, which will be breaking down less often.

Re: FTL rate of movement for GURPS SPACESHIPS
 

They are, however, much cheaper, so breaking down more often does not matter (and automation refers to control as well as maintenance). For example, the majority of SM+4 fighter-bomber drones are going to be around $1M, meaning that you can get six of them for the cost of one SM+5 fighter-bomber drone with Total Automation. Since they are disposable, the breakdown chance does not terribly matter.

Re: FTL rate of movement for GURPS SPACESHIPS
 

Dumb question:

Why does High Automation require size 12+ vessels, but Total Automation has no size requirement?

High Automation costs 20% less than Total automation, and can reduce up to 90% of the workstations required for the ship in question.

Just seems odd.

Either way, there doesn't seem to be any maintenance rules in effect when dealing with GURPS SPACESHIPS - unless it is present in the only rule set I didn't purchase (#7).

In any event, heavily automating starships or total automation makes for a Beserker style campaign - and frankly, that seems like a shame in my eyes.

Moving on to the other rules, it would seem that smaller craft do suffer a penalty where it comes to complexity of computer systems carried on board. This in turn, when coupled with the rules on page 14 of SPACESHIPS #4, make it such that depending on the Tech level, the IQ of the computer driven AI becomes considerably lower.

I won't make a big deal about it, but I largely detest the rules for Robots and AI's in Ultratech for 4e as compared against Ultratech or Robots for 3e. In effect, AI's are now built with character points rather than anything else (or so it seems to me).

Just for giggles? Would someone build (step by step) a functional Complexity 6 AI for use with a TL 10 Hull size 5 vessel?

I'd like to get a feel for what such a vehicle's functional skills would be like when contrasted against a ship whose crew might be trained to skill level 12 as a general rule.

Re: FTL rate of movement for GURPS SPACESHIPS
 

For the practical reason that High Automation reduces the workspace requirement by a factor of 10, and at SM 11 and below each system has less than 10 workspaces. At SM 9 and below systems don't even have workspace requirements (except for the Engine Room).

This would result in ships with High Automation needing to keep track of partial workspace requirements, which is messy and against the core KISS tenant of the Spaceships rules. It would also have some odd results in dealing with damaged/destroyed systems and where the workspaces actually are. I could certainly see a case being made for allowing SM 10-11 ships to have High Automation and simply apply the reduction to the total workspace requirement for the ship, with a minimum of one workspace.

Re: FTL rate of movement for GURPS SPACESHIPS
 

What I did for my rough costing exercise (which involved split systems in an SM+12 ship) was to round up the crew requirement in each highly-automated SM+11 system from 0.3 to 1. But since I was assuming a three-watch crew anyway I could have gone with giving each such system a technician in one watch out of three.

Re: FTL rate of movement for GURPS SPACESHIPS
 

I assume that this is as ericbsmith suggests, because you can't cleanly reduce a crew requirement by 90% that isn't a multiple of ten.

Is that right? My read is that total automation is G$5 million per workstation i.e. G$5 million per technician on watch saved, whereas high automation is G$1 million per workstation i.e. G$1.11 million per technician on watch saved i.e. 78% cheaper.

Not in #7. I figure that by taking an interest in maintenance costs I am playing wrongly.

I, too, am dissatisfied with this approach. It obscures the incentives that drive the behaviour of PCs, NPCs, and institutions.

Re: FTL rate of movement for GURPS SPACESHIPS
 

That's not a bad approach for SM+11 ships, as it keeps things simple.

For SM+10 the number of workspaces are almost certainly going to be less than 10, and by necessity they are less than 20, so you could just assume that it reduces the workspaces to 1 for the entire ship; or optionally 2 if the ship requires 11+ workspaces normally.

For SM+9 the only workspace requirement is the Engine Room, which has two workspaces, so reducing that to one is logical.

For SM+8 and below reducing workspaces is meaningless since an Engine Room only requires one workspace.

Re: FTL rate of movement for GURPS SPACESHIPS
 

No, that's not right. You have at least three watches on a merchant ship. Each workspace is G$400,000 per year if totally automated, but it's G$212,790 per year if served by three shifts of Merchant Rank 0 technicians in bunkrooms (G$239,790 per year if the techs get cabins). No wonder, then, that high automation works out in my model. It costs G$88,889 per year per workspace eliminated, which is a lot cheaper than three shifts of techs.