Thursday, March 16, 2017

Spaceships Quickie: A Spaceship for any Size and for any Occasion

Since my last post covering a few optional systems for GURPS Spaceships went over so well I figured I might as well keep the ball rolling.

While the system gives you a good range of sizes to pick from, from SM+4 up to SM+15 but... what happens in you want a ship bigger or even smaller?

Well, wonder no more!

Below is a extended hull table covering ship sizes from a partly SM0 all the way up to a massive SM+31!

Of course how boring would it be if I just gave you the same data the books do? So I figured I'd throw in a few extra tidbits you guys might find useful. Since Spaceships on pg. 9 lets us know that the ships were figured as unstreamlined  cylinder I used that data to give you not only the radius of the ships end caps but the ship but in another table below I also show you what the volume and surface area for a given SM is!


Extended Hull Table

SM Loaded Mass         Length                                   Radius                                       dST/HP            Hnd/SR
0        0.1                      2 yards (6ft)                           0.2 yards (0.6ft)                         3                      +2/2
+1      0.3                      3 yards (9ft)                           0.3 yards (0.9ft)                         5                      +1/3           
+2      1                         5 yards (15ft)                         0.5  yards  (1.5ft)                       7                      +1/3   
+3      3                         7  yards (21ft)                        0.7 yards (21ft)                          10                    +1/3
+4      10                       10 yards (30ft)                       1     yards  (3ft)                          15                      0/4
+5      30                       15 yards (45ft)                       1.5  yards  (5ft)                          20                      0/4
+6     100                      20 yards (60ft)                       2     yards  (6ft)                          30                      0/4
+7     300                      30 yards (90ft)                       3     yards  (9ft)                          50                    -1/5
+8     1,000                   50 yards (150ft)                     5     yards  (15ft)                        70                    -1/5
+9     3,000                   70 yards (210ft)                     7     yards  (21ft)                        100                  -1/5
+10   10,000                  100 yards (300ft)                 10  yards  (30ft)                          150                  -2/5
+11   30,000                   150 yards (450ft)                 15  yards  (50ft)                         200                  -2/5
+12   100,000                 200 yards (600ft)                 20  yards  (60ft)                         300                  -2/5
+13   300,000                 300 yards (900ft)                 30  yards  (90ft)                         500                  -3/5
+14   1,000,000              500 yards (1,500ft)              50  yards  (150ft)                       700                  -3/5
+15   3,000,000              700 yards (2,100ft)              70 yards   (210ft)                       1,000               -3/5
+16   10,000,000             1,000 yards (3,000ft)          100 yards (300ft)                       1,500               -4/5
+17   30,000,000             1,500 yards (4,500ft)           150 yards (500ft)                      2,000               -4/5
+18   100,000,000           2,000 yards (6,000ft)            200 yards (600ft)                     3,000               -4/5
+19   300,000,000           3,000 yards (9,000ft)            300 yards (900ft)                     5,000               -5/5
+20   1,000,000,000        5,000 yards (15,000ft)          500 yards  (1,500ft)                 7,000               -5/5
+21   3,000,000,000        7,000 yards (21,000ft)           700 yards  (2,100ft)                10,000            -5/5 
+22   10,000,000,000      10,000 yards (30,000ft)         1,000 yards (3,000ft)              15,000            -6/5
+23   30,000,000,000      15,000 yards (45,000ft)         1,500 yards (5,000ft)              20,000             -6/5
+24   100,000,000,000     20,000 yards (60,000ft)         2,000 yards (6,000ft)             30,000             -6/5
+25   300,000,000,000      30,000 yards (90,000ft)        3,000 yards (9,000ft)             50,000             -7/5
+26   1,000,000,000,000   50,000 yards (150,000ft)       5,000 yards (15,000ft)          70,000             -7/5
+27   3,000,000,000,000    70,000 yards (210,000ft)      7,000 yards (21,000ft)          100,000           -7/5
+28   10,000,000,000,000   100,000 yards (300,000ft)    10,000 yards (30,000ft)       150,000           -8/5
+29   30,000,000,000,000   150,000 yards (450,000ft)     15,000 yards (50,000ft)      200,000           -8/5
+30   100,000,000,000,000  200,000 yards (600,000ft)     20,000 yards (60,000ft)     300,000           -8/5
+31   300,000,000,000,000  300,000 yards (900,000ft)    30,000 yards  (90,000ft)    500,000         -9/5

Hull Structural Data Table
Volume is in cubic feet and SA is the ships surface area in square feet.

SM  Volume                                   SA                         
0          10                                       30                             
+1        30                                       60                            
+2        100                                     150                          
+3        300                                     300                         
+4        1,000                                  600                            
+5        3,000                                  1,500                        
+6        10,000                                3,000                       
+7        30,000                                6,000                              
+8       100,000                               15,000                     
+9       300,000                               30,000                      
+10     1,000,000                            60,000                      
+11      3,000,000                           150,000                    
+12      10,000,000                         300,000                                   
+13      30,000,000                         600,000
+14      100,000,000                       1,500,000
+15      300,000,000                       3,000,000
+16      1,000,000,000                    6,000,000
+17      3,000,000,000                    15,000,000
+18      10,000,000,000                  30,000,000
+19      30,000,000,000                  60,000,000
+20      100,000,000,000                150,000,000
+21      300,000,000,000                300,000,000
+22      1,000,000,000,000             600,000,000
+23      3,000,000,000,000             1,500,000,000
+24      10,000,000,000,000           3,000,000,000
+25      30,000,000,000,000           6,000,000,000   
+26      100,000,000,000,000         15,000,000,000
+27      300,000,000,000,000         30,000,000,000
+28      1,000,000,000,000,000      60,000,000,000
+29      3,000,000,000,000,000      150,000,000,000
+30      10,000,000,000,000,000    300,000,000,000
+31      30,000,000,000,000,000    600,000,000,000 

Now just in case this expanded table is not enough for you (and let's face it, might as well push things as far as you can go), it's pretty easy to keep it going. As you might of noticed, everything follows a nice and neat pattern of progression.

The ships loaded mass follows a 1-3 progression increased by a factor of 10 every time the pattern repeats.

Length in yards follows the every versatile SS/R tables progression of 1, 1.5, 2, 3, 5, 7 and 10 with the pattern going up by a factor of 10 every time it repeats. 

The radius in yards is equal to the length/10.

dST/HP follows the same sort of  1, 1.5, 2, 3, 5, 7 and 10 pattern as the the ships length.

Handling goes down by 1 and SR goes up by 1 every three changes in SM. SR can not go higher then 5.

The ships volume is equal to 100 cubic feet per ton of mass.

The ships surface area follows a 3, 6, 15 progression which goes up by a factor of 10 every time it repeats.


What's that?

What if you want to be a non-conforming special snow flake and ditch the 1-3 progression so you can make a ship that's, oh I don't know, 2 or 50,000 tons?


That's all you need?

That's easy!

Now for most systems so long as you know the ships loaded mass you're G to G but there are a few systems that need to know the ships SM to work and in general you are going to need to know what SM the odd sized ship fall under.

To figure a ships SM use this formula: 2×Log10(ships loaded mass)+2. Round up to see what SM your ship falls under but use the full fractional number (though rounding it to 1 or 2 decimal places wouldn't hurt) to figure the stats of systems that work off a SMs,

To figure its length in yards use 15×(ships loaded mass/30)(1/3). Radius is 1/10th of the ships length. Surface area can be figured by converting length and radius to feet and figuring 2×π×radius×length+2×π×radius2. Ships volume is its loaded weight times 100.

And what they hey, what if you want to figure the ships loaded mass from its SM? Piece of cake. Ships loaded weight is equal to 10((ships SM-2)/2).

But wait! There's more!

What's the point of giving you more ship sizes to work off of if I wasn't also going to show you how to expand the systems you can load onto said ships to follow suit?

Below I will show you how to expand the various systems in GURPS Spaceships to fit into any sized hull you want.  I'm only covering the systems that have stats that change with SM (for example I don't cover Reactors since the amount of power points they gives does not change with SM) and I only cover systems from the first Spaceships book. I fired my brain trying to unwrap one book thank you very much heh but I will get back to systems covered in the future books in due time.

This is pretty simply. All costs follow two price points, one for odd SM systems and one for even SM systems, that repeats increasing/decreasing by 10 every time the pattern repeats. For example SM +5 Steel armor costs $6,000 dollars and SM +6 costs $20,000 dollars so if I'm right SM+7 steel armor should costs $60,000 and if we look it up on Spaceships pg 11, yep, that's what it costs. 

So for a quick way to work out what the cost of a system of any size is to subtract subtract 5 from its SM is your ship is an odd SM or 6 if its an even SM and then divide the difference by 2. Then raise 10 to the power of the remainder and lastly multiply the exponent by how much a SM+5 version of the system costs if odd or by how much a SM+6 version costs if even.

Example: To figure the cost of a SM+22 fusion rector first we subtract 6 from its SM since its an even SM getting a difference of 16 which then halved to 8. We then raise to to the power of 8 or 100,000,000 and then multiply that by the $1 million cost of a SM+6 reactor for a total cost of $100 trillion.

The number of workspaces a system needs is the same for a given SM no matter what system it is.

Number of workspaces is equal to ships loaded mass/10,000.

dDR: Ac×(ships loaded mass/30)(1/3). Round numbers off to match a 1, 2, 3, 5, 7, 10, and 15 progression.

Ac is 0.33 if ice, 0.5 if stone, 1.5 if steel, 2 if light alloy or organic, 3 if metallic laminate, 5 if advanced metallic laminate, 7 if nanocomposite, 10 if diamondoid, and 15 if exotic laminate.

If your ships is streamlined then use the weight of a ship one SM smaller.

Of course since I gave you guys the surface area of each size of ship some of you are going to want to play around use the greater range of options that the Cutting Edge and Ultra-Tech Armor Design systems give you. In that case remember that each system of armor only covers 1/3rd of the ships surface area.

And if you are interested, these are the WM for the armors used in Spaceships.

Ice:                                                        2.7                                                                                                Stone:                                                    1.8
Steel:                                                     0.6
Light Alloy or Organic:                        0.3

Metallic Laminate:                               0.2
Advanced Metallic Laminate:              0.12
Nanocomposite:                                    0.08
Diamondoid:                                         0.06

Exotic Laminate:                                  0.04

Cargo Hold
Cargo holds capacity is equal to ships loaded mass/20.

Control Room
Computer Complexity: 5+((ships SM-4)/2). Drop any fractions.
Comm/Sensor: SM-11.
Control Stations: 10((ships SM-4)/6). Round off.

Comm/Sensor Array
Array modifier is equal to SM-9.

$/hr: Ships Loaded Mass ×50.
Lbs/hr: Ships Loaded Mass/200.

Force Screens
TL11^: 10((ships SM+3)/6).
TL12^: 10((ships+4)/6).

Fuel Tanks
Fuel Capacity is equal to ships loaded mass/20.

Number of Cabins is equal to ships loaded mass/50. Round up after SM +6. [1]

Hanger Bay
Capacity: Ships loaded mass/30.
Launch Rate: Larger of capacity or 10((ships SM-4)/4).   

Jump Gate
Max Tonnage: Ships loaded mass/30.

Mining and Refinery
Tons/hr (mining): Ships loaded mass/200.
Tons/hr (refinery): Ships loaded mass/60.

Open Space
Areas: 10((ships SM-8)/3).

Passenger Seating
Seats: Ships loaded mass/15.


Beam Output
Major Battery: Equal to the loaded mass of a ship one SM smaller in mega joules (a 1 gigaton SM+20 ship would have a beam output equal to the loaded mass of a SM+19 ship or 300TJ).

Medium Battery: Equal to the loaded mass of a ship two SM smaller in mega joules.

Secondary Battery: Equal to the loaded mass of a ship three SM smaller in mega joules.

Tertiary Battery: Equal to the loaded mass of a ship four SM smaller in mega joules.

Spinal Battery: Equal to the ships loaded mass in mega joules.

Beam d-Damage
d-Damage is equal to (output/100)(1/3).

Gun/Missile base d-Damage
d-Damage is equal to Caliber in cm×1.5.

Gun Bore Size (in cm)

 10((ships SM+Gb)/13).

Gb is 8 if a major battery, 7 if a medium battery, 6 if a secondary battery, 5 if a tertiary battery and 9 if a spinal battery.

Weight per Shot

10((ships SM-Gw)/4).

Gw is 12 if a major battery, 13 if a medium battery, 14 if a secondary battery, 15 if a tertiary battery and 11 if a spinal battery.

Number of Shots

10((ships SM+Gs)/6).

Gs is 6 if a major battery, 5 if a medium battery, 4 if a secondary battery, 3 if a tertiary battery and 7 if a spinal battery.


Missile Bore Size (in cm)

10((ships SM+Mb)/13).

Gb is 12 if a major battery, 7 if a medium battery, 6 if a secondary battery, 5 if a tertiary battery and 9 if a spinal battery.

Weight per Shot

10((ships SM-Mw)/4).

Mw is 8 if a major battery, 9 if a medium battery, 10 if a secondary battery, 11 if a tertiary battery and 7 if a spinal battery.

Number of Shots

10((ships SM+Ms)/6).

Ms is 0 if a major battery, 1 if a medium battery, 2 if a secondary battery, 3 if a tertiary battery and -1 if a spinal battery.

Spin Gravity
Max G: 10((ships SM-14)/6).

[1] Fixed an typo. Number of habitats is equal to ships loaded mass divided by 50, not 150. Don't recall how the 1 got in there.


  1. Nice work, really really be nice ot see this in a Pyramid.

    1. I've been getting this a lot lately heh. I do have some Pyramid plans in the works but the ones I got in the works are originals.

      Once I can start moving forwards with them I'll see if they'll be ok with me using content on my blog as article fodder.

  2. Combine this, your post about missile, and the current post about power cells, and you've given me the tools to answer the questions I was about to ask.