Spelljammer/Battlesystem system

I wrote this up three years ago, when I first joined the list. Some recent
discussions brought it to mind so I dredged it up, reedited it, and here it
is. There's a siege weapon chart at the end which some may find useful. For
those who have this article from before, this version is far more complete,
the chart includes both space and ground stats now:)

Remember,  the info below does _not_ take the place of the spelljammer
rules nor the Battlesystem rules,  both would be needed for this to work.
Comments welcome.

Figures-Ships will most likely have to be scratch built,  try going to a
nature store and checking out some of their 3-d balsa wood insect models
for a lot of vessels, standard ships (like a galleon) can be taken from
plastic model kits.  The rules below are for 25mm,  for SJ 15mm would work
much better,  just read centimeters wherever inches appear.

Stats:  All creatures,  including PCs and other individuals,  should have
Battlesystem stats (I reccomend using the normal PHB memorization rules,
however)  Ships use their standard SJ stats w/ the following adjustments:
Hull Points=Battlesystem hits,  MC is one step _below_ standard SJ MC (ie a
Wa Locust (SJ MCA)  would be MC B in battlesystem turns). No spelljammer
can have MC A, MCs worse then E=move only in a straight line and up or
down.  SJs do _not_ have to move 1/2 their move to stay aloft, they can
hover/levitate.  SR converts to move as follows 1 SR = 24" move (I have a 1
SR limit for SJ vessels in the atmosphere, see my SJ Players' Primer).  If
a ship leaves the table,  it must stay off for 1 full turn before
returning,  and must return along the same table edge it left.  Standard AR
applies for SJs.

Play sequence: use standard Battlesystem sequence,  SJs move per their side.

Boarding/Melee-Use standard Battlesystem combat,  Remember the benefits a
ship can give (higher elevation,   wall,  ect).  I reccomend boarding
defenders use the Holding the Breech rules on Pg 80 of the Battlesystem
book.

Missile/artillery-I included Battlesystem stats for many SJ arty pieces at
the end of this post,  some new ones appear as well.  I reccomend looking
up John Warry's _Warfare in the Classical World_ if you want some ideas for
cool,  non-gunpowder weapons (as well as clear plans for several ancient
galley types).

A ship's crew always gets a -3 AR bonus against normal missile fire (being
screened).  Siege weapons go as follows: They may only fire during the
Missile phase,  and there fire follows the following sequence:
1. Declare Target
2. Roll Scatter %,  if scatter occurs use chart to determine if anything
was hit (use grenade chart from DMG)
2b.  If target is not a ship,  roll AD per Battlesystem and remove any losses
3. If target is a ship Roll d20 weapons Thaco vs Ships AR If roll shows a
miss,  that's the end,  if a critical check critical hit chart (War
Captains Companion)
4. Roll AD per Battlesystem,  mark off hits from hull points
5.  Roll AD versus _crew_  Crew gets AR checks (note, units/creatures only
get AR checks versus arty when aboard a ship or within a building or
structure)

Arty Thaco modifers:
-1 for each 4" target moved or moved last turn
-1 for each 6" firer moved or will move that turn
+10% scatter if arty is on a ship

Bombing
split fire or missile phase
AD 10
Scatter 50% (+40% if moving)  1d4" (1d12" if moving)
Thaco 18  critical 20

Magic-use standard Battlesystem,  but modify for ships according to the
guidelines in War Captains Companion and SJ boxed set.


Type            ROF     AD     Hull  HP   Thaco   CriticalScatter    RngMin

Lt. Ballista    1       10      0    2d6    16      n/a   5% 1d2"       0

Md. Ballista    1       d12     1d3  3d6    14      20    15% 1d3"      1"

Hvy Ballista    1/2     d12+d6 1d4+2 3d10   12      19+   20% 1d4"      1"

Lt Catapult     1/2     2d10    1d2  2d10   16      20    40% 1d3"      15"

Md Catapult     1/3     2d12   1d3+1 3d10   17      19+   50% 1d3"      18"

Hvy Catapult    1/4     3d10    2d4  3d10   18      18+   50% 1d6"      20"

Trebuchet       1/4     3d12    1d6  3d10   18      18+   55% 1d6"      24"

Arrow Catapult  1/3     2d6      0   3d6    17      n/a   60% 1d6"      6"

Bombard         1/4     3d12    1d6  2d10   19      18+   45% 1d4"      18"

Lt Cannon       1       2d8     1d2  1d10   15      20    10% 1d2"      1"

Hvy Cannon      1/3     2d12    1d4  2d10   17      19+   20%1d2"       1"

Swivel Gun      1/2     3d8      0   2d10   16      n/a     0           0

Galloper        1/2     2d10    1d2  2d10   15      20    20% 1d4"      1"

Scorpio         1/2     d12     1d2  3d6    17      19+   20% 1d3"      1"

Lithobolos      1/3     2d12    1d4  3d6    15      18+   30% 1d4"      1"

Fire Projector  1/4    2d10+fire1d3  sd10   16      18+     0           1"




Type           RngMax  SJRng  Hits    Crew    Move                 Point costs
Lt. Ballista    20"     6       6       1       6"                      30
Md. Ballista    27"     4       8       2       4"                      37
Hvy Ballista    30"     2       10      3       4"                      42
Lt Catapult     30"     5       10      4       4"                      30
Md Catapult     36"     4       15      6       3"                      37
Hvy Catapult    40"     3       18      7       2"                      42
Trebuchet       48"     6       20      8       nil                     48
Arrow Catapult  18"     1       8       3       4"                      25
Bombard         40"     2       10      2       nil     20%misfire*     70
Lt Cannon       36"     2       8       1       4"      10% misfire*    150
Hvy Cannon      36"     2       10      2       3"      15%misfire*     200
Swivel Gun      3"      0       6       1       6"      5% misfire*     25
Galloper        36"     2       6       4       6"      10% misfire*    125
Scorpio         40"     2       8       2       nil                     100
Lithobolos      40"     2       10      4       nil                     120
Fire Projector  20"     1       4       1       nil     20% misfire**   110

Misfire
2d4
2-3 Hang fire  reload
4-7 Automatic scatter
8-9 Explodes    1d4 hits w/i 1"
Bombards +1 on chart

* Large weapon causes 2d6 hit explosion and causes fire critical hit

Fire critical hit has cumulative 5%/turn to cause same effect

**  +1 chance for ship carrying this weapon to suffer a critical hit


"We look on the same stars,  the sky is common,  the same world surrounds
us.  What difference does it make by what pains each seeks the truth?  We
can not attain to so great a secret by one road..."
Symmachus,  "Memorial on the Occasion of the Removal of the Altar of
Victory from the Senate House" (392 AD)

Paul Westermeyer,  westermeyer.3@???.edu
Phd Candidate, History, Ohio State
Adjunct Faculty, Humanities Department, Columbus State Community College