[MC+SS] Alternate TS Calculation

[vierasmarius]

I figured I'd repost this here, since the thread I originally posted it in is the e23 forum, and this post is specific to GURPS. I'd love to hear people's feedback on this idea!

Originally Posted by vierasmarius

Just got this pdf, thoroughly enjoying it. I did have an observation though, in regards to the Mass Combat rules. Because of how price scales in Spaceships (proportional to Mass) compared to how DR and HP scale (proportional to linear dimension), larger ships have a much higher cost per TS than small craft and fighters (assuming equivalent systems devoted to armor and weapons). I had a thought on how to address this, by replacing the DR+HP portion with a formula based on Mass. Something like: Mass ÷ 10 x (1 + dDR ÷ dST)

This would have the effect of making a SM X ship the equivalent of 3 SM X-1 ships, 10 SM X-2 ships, etc. Compare to the rules as they stand, where 1 SM X = 2 SM X-2. It would make it much easier to represent the "Super Battleship", a single ship capable of fighting an entire enemy fleet, while also keeping in check the power of carriers with massive fighter complements.

I hope this isn't taken as a criticism of the article. On the contrary, I love the mechanic he's presented, and am currently in the process of applying it to all of the published spaceships. So take this more as a musing than a complaint, as a slightly different way to represent spaceships in MC.

EDIT: Another way to think of it that comes to mind. You have a SM+5 fighter with a Spinal weapon mount, and a SM+6 fighter with the same weapon in a Major mount, and the smaller ship has double the TS of the larger one (3 x 20 vs 1 x 30). If this is based on Mass instead, they'd be roughly equal TS (3 x 30 vs 1 x 100).

A specific example of the change this would have: The Meteor Aerospace Fighter and the Shrike Fighter-Bomber are of comparable TL (9^ and 10) and have similar loadouts. The Meteor is SM+5, with one Major battery (a VRF 25mm cannon) and 2 Medium batteries (6x16cm launchers). Its TS is 5000. The Shrike is SM+6, with a Major battery Laser and a Secondary battery of missile launchers, 10x16cm. Its TS is only 3900, despite having nearly double to firepower, better HP and DR, and comparable maneuverability. Using my alternate option, they'd be TS 750 and 1300 respectively, which (IMO) better matches their differing power and utility. Of course, you can tweak the equation's constant (I divided Mass by 10, but you could use a higher or lower value), but the important thing is relative strength between spaceships.

[Langy]

I had this same exact concern. I'm curious if David Pulver had a reason to make TS not scale with cost.

[vicky_molokh]

Originally Posted by Langy

I had this same exact concern. I'm curious if David Pulver had a reason to make TS not scale with cost.

An attempt to make fighters useful? ;)

[vierasmarius]

Originally Posted by vicky_molokh

An attempt to make fighters useful? ;)

Hehe, that could be. They still seem to have some use as it is, since they benefit from better Handling and can devote a higher percentage of their systems to combat. But granting an SM+11 Carrier with Heavy Fighters four times the TS of an SM+11 Battleship of the same TL... that seems a bit too useful. There are some settings where this might be appropriate of course; Star Wars and BSG seem obvious examples. In such a campaign I'd probably give a discount to large vessels, to give some justification for why people bother with them.

[David Johnston2]

Originally Posted by vierasmarius

Hehe, that could be. They still seem to have some use as it is, since they benefit from better Handling and can devote a higher percentage of their systems to combat. But granting an SM+11 Carrier with Heavy Fighters four times the TS of an SM+11 Battleship of the same TL... that seems a bit too useful. There are some settings where this might be appropriate of course; Star Wars and BSG seem obvious examples. In such a campaign I'd probably give a discount to large vessels, to give some justification for why people bother with them.

In the real world, people bother with battleships for their ship to shore bombardment capability.

[Peter Knutsen]

I haven't bought the #30 Pyramid, but it seems to me there are three classes of ship:

1. Short occupancy ships wth no FTL. These are able to devote many module slots to weapons and defence, and sensors and ECM and so forth, so they should have a high TS for their size.

2. Long occupancy ships with no FTL. Medium TS for their size.

3. Long occupancy ships with FTL. Low TS for their size.

[Langy]

Originally Posted by Peter Knutsen

I haven't bought the #30 Pyramid, but it seems to me there are three classes of ship:

1. Short occupancy ships wth no FTL. These are able to devote many module slots to weapons and defence, and sensors and ECM and so forth, so they should have a high TS for their size.

2. Long occupancy ships with no FTL. Medium TS for their size.

3. Long occupancy ships with FTL. Low TS for their size.

All those things are well-covered by the multipliers for number of weapon batteries, ECM, and DR. As-is, a ship that costs ten more might provide only twice as much TS, even if it's built in the same exact fashion with the same exact modules (just 10 times as big). It only gets worse as the difference in SM (and thus price) goes up.

I'd suggest a different new formula than the one viera suggested, though. You could try:

Avg dDR*dHP*dHP*HF*WB*TF / 200

This would make the Battle-class frigate TS 729,000, which is much closer to the TS 768,000 you could get with two TL10 nuclear submarines for roughly the same price. Viera's formula would get a TS of 205,000, but is much more complicated.

Note that dDR*dHP*dHP scales almost directly with mass (and thus cost), and it makes the formula nice and pretty.

EDIT: After looking at how much Air vessels cost compared to other ones, I think spaceships being really expensive for their TS is appropriate - maybe divide by 1,000 or so instead of 200. It's still not appropriate for fighter-sized ships to be super-cheap for their TS compared with capital ships, though.

[vierasmarius]

Originally Posted by Langy

All those things are well-covered by the multipliers for number of weapon batteries, ECM, and DR. As-is, a ship that costs ten more might provide only twice as much TS, even if it's built in the same exact fashion with the same exact modules (just 10 times as big). It only gets worse as the difference in SM (and thus price) goes up.

I'd suggest a different new formula than the one viera suggested, though. You could try:

Avg dDR*dHP*dHP*HF*WB*TF / 200

This would make the Battle-class frigate TS 729,000, which is much closer to the TS 768,000 you could get with two TL10 nuclear submarines for roughly the same price. Viera's formula would get a TS of 205,000, but is much more complicated.

Note that dDR*dHP*dHP scales almost directly with mass (and thus cost), and it makes the formula nice and pretty.

That should work well for the most part, though DR is much more variable than HP (ranging from 5% to 70% of HP per armor system, or up to 300% for a Force Screen). I think including it there, rather than adding it to HP, might be weighting it too heavily.

I had another thought, while fiddling with the numbers for Carriers. If we go with TS = Mass, there's little to no reason to use fighters instead of just more guns. A single fighter of SM X-3 (ie, the largest fighter that will fit in a given hangar) weighs 1/30 of the capital ship, and replaces a gun emplacement that would weigh 1/20 of the capital ship. Assuming a heavy fighter loadout, it could have maybe 30% of it's systems devoted to weapons. Assuming good armor and handling it would have a TS of maybe 25%-30% of the gun that it's replacing. In this model the carrier would be better off just with another gun emplacement.

Under some conceptions of space warfare, this would work fine - Fighters would be a niche weapon for orbit-to-surface attacks or spacelane patrols. But it doesn't match the trope of "Space Superiority Fighters" as a key component of the larger battlescape. So perhaps a compromise. Instead of scaling TS with the linear dimension (the model presented in the article) or with the mass (my proposal above), instead scale with the surface area. This would give that heavy fighter I talked about above a TS equivalent to about 60%-80% of one capital ship weapon mount, which seems fair enough that carriers would be useful. And there's a very simple way to handle this formula too: Just multiply the TS calculated using the original formula by the ship's length divided by some constant, probably 20 (so a SM+6 fighter keeps it's original TS, the smaller fighters drop a bit, and everything above gets a boost). So that Battle-Class Frigate from the article would go from TS 68,580 to about 240,000. Capital Ships would still be more expensive than the same TS of Naval vessels, and larger ships would still be proportionally more expensive than smaller ones, but it's a bit less jarring a discrepancy, and it keeps Carriers in the ring.

[Peter Knutsen]

Can GURPS Spaceships even give a cost discount for short-occupancy ships? I forgot...

[Langy]

Originally Posted by Peter Knutsen

Can GURPS Spaceships even give a cost discount for short-occupancy ships? I forgot...

Yes. They require significantly fewer systems for life support or habitats, possibly all the way down to 'none' if the 'short-occupancy' bit means something more like a fighter than a patrol boat.

That should work well for the most part, though DR is much more variable than HP (ranging from 5% to 70% of HP per armor system, or up to 300% for a Force Screen). I think including it there, rather than adding it to HP, might be weighting it too heavily.

This is intended. If something has twice as much DR, then they get twice as much TS, etc. I suppose you could do (HP+DR)^3, but I like HP*DR more.

I had another thought, while fiddling with the numbers for Carriers. If we go with TS = Mass, there's little to no reason to use fighters instead of just more guns. A single fighter of SM X-3 (ie, the largest fighter that will fit in a given hangar) weighs 1/30 of the capital ship, and replaces a gun emplacement that would weigh 1/20 of the capital ship. Assuming a heavy fighter loadout, it could have maybe 30% of it's systems devoted to weapons. Assuming good armor and handling it would have a TS of maybe 25%-30% of the gun that it's replacing. In this model the carrier would be better off just with another gun emplacement.

This matches the general Spaceships system rather well - there's little point to using fighters in it. Still, if you do want to make it scale with surface area, do DR*HP instead of DR*HP*HP.