Topic: Scaling encounters for vehicular combats

[pyrotech]

I've been neglecting my HARP Sci-Fi adventure recently, but plan on getting back to work on it soon.  I'm at a point where I need to start detailing the encounters, and 80% of them will be space vehicular combats. 

Has anyone worked out guidelines for planning expected challenge levels for these kinds of encounters?  I've got my own "gut feelings" and will run a practice game or two before finishing it, but I would like to have to tweak as little as possible after playtesting and get the difficulty right the first time.

[NicholasHMCaldwell]

What type of ship are the PCs in? How many PCs and or friendly NPCs / AIs are there for the various stations aboard  the ship? How many weapons and what is the weapon attack sizes? At least to begin with you should avoid giving them ship board bonuses.

For a scoutship or light armed freighter, going up against same or a pair of starfighters is usually a fair fight. Corvettes are more challenging as are more fighters. Frigates, destroyers and cruisers will imperil all but the best player teams. I have had my players get involved in full-blown space battles duking it out with much bigger ships but by that time their ship was state of the art, the PCs were 10th lvl plus and the group had gelled.

bedt wishes,
Nicholas

[pyrotech]

Thanks for the response Nicholas - I know you are being kept busy!

The ship is an brand new but out of date gun ship (stats are below)

(click to show/hide)

Ship Type: Combat Shuttle –Gunboat
Ship Class: Phalynx -GB
Cost: 105.5M sol
Mass: 665 tons loaded mass
Accommodations: Bunks for 10, small medical bay, common/briefing room, 2 toilet/showers, small galley. 100 man/days life support/provisions (500 man/days additional life support and provisions in cargo bay)
Cargo: 25 tons cargo (typically 10 tons of ammunition (Autocannon: 50 shots -1min/rd or 1000 shots - 2sec/rd; PD: 300 shots - 1mn/rd or 4,500 shots - 2sec/rd), 2 tons additional provisions, 5 tons additional fuel, 3 tons empty or incidentals, 5 tons capacity empty)
Powerplant:  140 early minifusion reactors with 250 canisters fuel (12.5M En total + cargo fuel)
Combat Specifications:  Init -6, Hits 61, Armor 20, Shields 20, EW 10, PD 10, Man 9
+0 Small Lasercannon, +0 small Autocannon
Acceleration and Maximum Safe Speed: 600 G/ 0.07C speed
Power Use:  199,500 En/hr at Cruise speed, 399,000 En/hr at full speed, 665 En to jump
The Lasercannon uses 150 En/shot in 2 sec/rd combat or 2,500En/shot in 1min/rd combat.
Uses 9975 En /minute during combat maneuvers, or 333 EN per combat round.
Sensor Systems:  Early Sensor System (RI 0.5 light second, capable of Biological, Construct, Planetary, and Stellar Analysis)

The enemy crafts will be technically superior but with inferior crew and some design flaws. 

Silth Pilot:

(click to show/hide)

Generic - Silth Frontier Pilot (1)
EP:          +76             PEP:        -17           Init:    +13  DB:      +24       BMR:  2.8                   
RR Bonuses:   Stamina +35 Will +17 Magic -13                                                                             
                     St:           66           +7                                  SD:       51          +1                                           
                     Co:          61            +5                                  Qu:      71          +7                                             
                     Ag:          81            +9                                 Re:         56         +2                                             
                     In:           76           +6                                  Pr:         46         +2                                             
Weapon Skills:                                                                                                                                                                 
                            MR: 2HEn (Assault Blaster)             +36                               
                            MR: 1HP (Pistol)                                    +21                               
                            Gunnery: Direct Fire                           +38                               
                            Gunnery: Modern Missiles             +33                       
Armor:          Space Suit                                                                                                           
                                                                                                                                             
Talents:         Pilot Level Bonus (Pilot Starship), Heat Resistance (minor), Natural Weapon (Claws), Poison Sac, Natural Astronaut, Cold Susceptibility                                                                                                                   
Key Skills:      Climbing (4) +36, Brawling (2) +26, CS&M: Combat Driving/Piloting (5) +40, Gunnery: Direct Fire (5) +38, Gunnery: Modern Missiles (4) +33, MR: 2HEn (Assault Blaster) (4) +36, MR: 1HP (Pistol) (1) +21, Computer Operation (2) +18, Crafts: Stonemasonry (3) +26, First Aid (2) +18, Language: Other Racial (S) (6) +38, Language: Other Racial (W) (6) +38, Language: Racial (S) (4) +28, Language: Racial (W) (3) +23, Machine Op: Communications (2) +21, Lore: Own Culture (1) +9, Lore: Cosmography (1) +9, Lore: Geography (1) +9, Perception (3) +22, Resistance: Stamina (1) +35, Resistance: Will (1) +17, Signaling:Sensors and Countermeasures (3) +23, Vocation: Crewmember (3) +19, Foraging/Survival: Dessert (1) +13, Navigation: Astrogation (2) +18, Tracking (1) +12, Armor Skills (4) +36, Endurance (6) +76, Jumping (1) +21, Swimming (1) +21, Zero-G Maneuvering (3) +35, Stalking & Hiding (1) +15, Magnetogravitic Engineering (2) +18, Transport Engineering (2) +18, Weapons Engineering (2) +18, Air Pilot: Airplane (4) +35, Driving: Conventional (4) +35, Marine Pilot: Surface (1) +20, Space Pilot: Starship (6) +55                                                     
Resistance:     Magic (0) -13, Stamina (1) 35, Will (1) 17                                                                 
Languages:    Warspeach (S6/W6): 38/38, Highspeach (S4/W3): 28/23       

And the Silth Ships:

(click to show/hide)

Hasst Family
Silth Raider Ship
“Caiman” Assault Shuttle
Avail: R
Cost: 80M
Mass: 900 tons
Passengers: 30 plus 5 crew
Cargo 750 tons
Speed: 0.05c/600g
Power: 75F (500)
Interlock to Starship
Init: -6
Hits: 60
Armor: 20
Shields: 10
Electronic Warfare: 10
Point Defense: 10
Maneuverability: 9
Weaponry: +0 Small Laser, +0 Small Particle Beam, +0 tiny warhead (x4)
First encountered in 2468 by the Last Leg lost colony, these raider ships are used by the Hasst Family to destroy system defenses and perform boarding actions or small unit ground assaults.  Somewhat smaller than Astronavy assault shuttles, these tend to perform worse in protracted battles but have better surge firepower and orbital bombardment capabilities.  Dubbed the “Caiman” by Last Leg defenders, this vessel was the workhorse of the Silth attack on the Last Leg colony.  The Caiman interlocked to the larger “Gator” Raider ship.

Hasst Family
Silth Raider Ship
“Gator” Raider Mothership
Avail: R
Cost: 500M
Mass: 5000 tons
Passengers: 180 + 20 crew
Cargo: 1000 tons
Speed: 0.03C/300g
Power: 400F (3000)
Interlocks for 6 Assault Shuttles or 12 Fighters
Init: -6
Hits: 100
Armor: 20
Shields: 10
Electronic Warfare: 10
Point Defense: 10
Maneuverability: 9
Weaponry: +0 Small Laser (x4), +0 Medium Particle Beam (x2), +0 Medium warhead (x2)
First encountered in 2468 by the Last Leg lost colony, these raider ships are used by the Hasst Family to transport smaller raider shuttles and fighters in FTL travel.  These ships are also used to coordinate the actions of the shuttles and fighters during an attack.  Smaller than an Astronavy corvette, these vessels perform poorly to similarly sized vessel one on one.  Considerable speed and firepower was sacrificed in order to carry and support the interlocked vessels.  Dubbed the “Gator” by Last Leg defenders, this vessel was the primary command and transport component of the Silth attack on the Last Leg colony.  During the Last Leg attack several Gators were noted to carry 3 Caiman and 6 Geckos interlocked.

Hasst Family
Silth Raider Fighter
“Gecko” Raider Starfighter
Avail: R
Cost: 8M
Mass: 90 tons
Passengers: 1 crew
Cargo: 2.5 tons
Speed: 0.07C/600g
Power: 2F3 (10)
Interlocks to Starships
Init: -6
Hits: 35
Armor: 20
Shields: 10
Electronic Warfare: 10
Point Defense: none
Maneuverability: 9
Weaponry: +0 Small Laser , +0 tiny warhead (x2)
First encountered in 2468 by the Last Leg lost colony, these raider ships are used by the Hasst Family to engage lightly armed craft singly, or work together to engage larger craft.  Another design smaller than the equivalent Astronavy design, this fighter packs additional firepower but at the expense of survivability.  Called the “Gecko” by the Last Leg colony, this design was used to devastate the colonies non-military presence.  As many as 12 of these fighters could be interlocked to a carrier ship for FTL travel.  The greatest weakness of this craft noted by the Last Leg defense force was the fact that it was a single pilot craft.  The pilot was simply too busy to be able to fully utilise the technical and numeric advantages of these fighters. 


Hasst Space Missiles accel at 900g to .1c for a maximum chase range of 1Million km.

In many of the encounters the PCs will be part of a larger fleet and be able to use Squadron engagement rules.  In most encounters they will have numeric advantages, but attrition will begin to eat its way through the fleet as the adventure goes along.  By the end they are most likely going to be alone.

AIs will be practically non-existent in this adventure (they are at a lost colony at the end of the Human-Silth War encountering a similarly backwoods Silth Clan).

I was kind of guessing 1 gunboat could reasonably take on 2 fighters or 1 raider and expect to win.  I'm not sure how many gunboats (or the very similar missile boats in the fleet) would be needed to drop the larger psudo-corvette.  The Silth have better reactors, slightly better weapons, and better sensors - but their craft are weaker than the modern Astronavy equivelants and their pilots are not too great.

Thanks again for the feedback!

[markc]

 I have not read my HARP Sci Fi in a while but IMHO secondary equipment like life support is a must for many craft in the military. Just think one simple crit and the crew is without life support and better be wearing space suits or be able to get into them quickly. Also the secondary systems take up space and mass and IMHO would up the mass of all ships if required by law.


MDC

[pyrotech]

I agree with you markc,

If I were building a spacecraft I would want at least 3 parallel sets of life support located in different sections of the ship.  That gives you one to run, one as a backup in case of a failure, and one to be down for maintenance/repair.  But Harp Sci-Fi doesn't really dig into that level of detail on ships and equipment. 

When calculating the weight of passengers/crew and their life support needs for a ship I just use my rough figure of 150kg per passenger/crew + (50 kgs * (a occupancy factor) * (a cabin factor)) + food/water/air needs. 

The occupancy factor is still something I am banging on but right now is 1 for short occupancy (<8hrs), 2 for medium occupancy (9-16 hrs), 4 for long occupancy (17hrs - 2 days), 8 for extended occupancy (3 - 90 days), or 10 for indefinite oppupancy (>3months).  And the cabin factor is 0.5 for open cockpits (motorcycles), 1 for cramped cockpits (jet fighters), 2 for normal cockpits (cars), 3 for roomy cabins (locomotive cabin), 4 for bigger yet cabins.  I still haven't balanced these numbers with the examples in the book.

For the food/water/air requirements I just looked at the US military documents on the weight of various storage term provisions.  I don't have them handy now or I would list them.  But I did find them on the internet without too much trouble.

But I'm still kind of guessing on the challenge rating of space encounters.  Maybe I'll try to build a Pareto chart for the various relevant factors (crew skill, speed, maneuverability, init, hits, armor, shields, PD, weapons, etc.).

[markc]

In general I try and run a test encounter (or one that is in the PCs). Then I extrapolate from there on the fly. In a home game it is not such a big deal butif you are building for a publishedadventure or a con event it is much tougher on you to do so.
MDC

[markc]

 Your above info also reminded me of BattleTec as it has a tec superior and skill superior force going against a force that has less tech and in general not as good skills.
  If I was to just guess at a number I might say the advanced tec would be a 2 to 3 ratio or a 4 to 5 ratio. But again that is a force guess if you can make the weapons and ships have some grading number vs the players and their grade.


MDC