Spacejammer Combat
11/04/00
This is a
document is third in a series of conversion notes and house rules. It makes references to concepts introduced
in the other documents, so I recommend you read them in order. The entire series is available at my web site.
This
document represents two major changes to the standard Spelljammer rules. First, it includes a number of conceptual
changes to the Spelljammer setting, with house rules affecting a number of
small but significant elements of the game.
Second, it is a conversion of that modified setting to the new D&D
"3rd edition".
While I considered splitting these into two separate documents, one for
changes to the setting in 2e and another to convert to 3e, I ultimately decided
that was going to be too much work. For
those who intend to use Spelljammer with its original 2nd edition
AD&D rules, there may still be some conceptual ideas and house rules in
this document that you may find interesting, but some of them will need to be
backwards-converted to 2e.
This
document also contains a LOT of ideas that are not my own. I've been influenced by several members of
the Spelljammer-L mailing list and various web page authors, which I've listed
in the Notes and Bibliography section.
Due to the
extensive conversion information in this document, and some difficult design
decisions, I've included notes about why I have converted certain elements of
the game in the fashion I did. These
design notes will be separated from the normal text and placed in
"sidebars".
|
Term |
Abbrev. |
Definition |
|
Spacejam,
Spacejammer, Spacejamming |
SJ |
These
terms refer to travel through space, and have no implication for the nature
of propulsion being used. More
specific terms do have specific connotations, where lifejammer vessels make
use of lifejamming helms, spelljammer vessels make use of spelljamming helms,
etc. |
|
Normal
Scale |
NS |
This
is a term to differentiate between Ship Scale and Normal Scale combat. Normal Scale combat uses hit points, armor
class, melee weapons, 6 second rounds, and the normal 3e rules. |
|
Ship
Scale |
SS |
This
is a term used to differentiate between Normal Scale and Ship Scale
combat. Ship Scale combat uses
Structure Points, Hardness Ratings, Evasion Ratings, heavy weapons, one
minute turns, and my other modified rules for ship-to-ship combat. |
|
Round |
-- |
A
round is a standard 3e six second round. |
|
Turn |
-- |
A
turn is one minute, or 10 rounds in 3e. |
|
Hex |
-- |
A
hex is 500 yards, the same as a 2e SJ hex. |
|
Tactical
SJ Speed |
-- |
A
vessel moving at tactical speeds will cover one or more hexes per turn, based
on its Speed Rating. |
|
Full
SJ Speed |
-- |
A
vessel moving at full SJ speed is moving at approximately 100 million miles
per day in a straight line. |
|
Speed
Rating |
SR |
A
ship's Speed Rating is the number of hexes it can travel per turn (10
rounds). |
|
Maneuver
Rating |
MR |
A
ship's Maneuver Rating represents how quickly, easily and accurately a vessel
can turn. |
|
Evasion
Rating |
ER |
This
is the ship scale version of armor class.
It represents size, design and maneuverability. Unlike AC, it does not represent armor or
materials used in the vessels construction. |
|
Hardness
Rating |
HR |
This
is my implementation of the 3e Hardness concept in the ship scale system. |
|
Structure
Points |
SP |
This
is my equivalent of Hull Points. I changed
it to Structure Points both because it is a more accurate term, and the
abbreviation won't be confused with Hit Points. |
|
Spacejammer
Tonnage |
Ton |
An
SJ Ton is a measure of size and volume, not mass or weight. An SJ ton is 100 cubic yards, or 2,700 cubic
feet. |
The basic
rules for normal, person-to-person combat remain the same as in 3e
D&D. Initiative, combat rounds,
attack and damage rolls all remain the same.
Below are some clarifications and small modifications for normal scale
combat in Wildspace and the Flow.
Combat in
weightless conditions imposes a -2 on all attacks, saves and checks, and -10 on
initiative. In addition, characters
lose any dodge bonus to AC, and are therefore vulnerable to a rogue's Sneak attack,
but only if the rogue is himself not weightless (for example, if he is on deck
and using a ranged weapon within 30').
Characters
who take the Wildspace Familiarity feat do not suffer the penalties to attacks,
saves, checks or initiative, but still lose their dodge bonus to AC. Characters who have some form of mobility in
zero-gravity (for example, the ability to fly) do not lose their dodge bonus
regardless of whether or not they have the Wildspace Familiarity feat. Also, creatures that are native to Wildspace
never suffer these penalties.
Keep in
mind that in space, each hex represents 500 yards across, so spell ranges are
quite limited. It is recommended that
the DM should be generous in judging spell ranges. Remember that if your ship is in the center of the hex, any other
ship in the same hex is probably about 300' away on average, but could be
closer or further. Giving players (and
NPCs!) the benefit of the doubt, I recommend allowing any spells with at least
a Medium (100'+10'/level) or Long (400'+40'/level) range to be cast on any
target in the same hex.
However,
regardless of the spell's range, some spells only work when the air envelopes
are mixed because they can not penetrate a void.
|
Missile
weapons within a gravity field function normally in all respects. However, outside a gravity field, a
missile will continue unimpeded in a straight line until it hits
something. Normally, thrown weapons
have a maximum range equal to 5x their range increment, while projectile weapons
have a maximum of 10x their range increment.
If those maximum ranges are not sufficient to propel the missile
outside the gravity field, the normal rules apply. However,
if the gravity field ends before the missile reaches it's maximum range, then
the missile will continue unimpeded in a straight line. This allows a character to theoretically
attack anything that is in his line of sight, no matter how far away,
provided it is outside a gravity field.
Unfortunately, given the distances involved, it is not always that
straightforward, because thrown missiles travel at only 1 hex per round,
while projectiles travel 2 hexes per round. It is
relatively simple to attack stationary targets in wildspace. Treat the target as if it were at the edge
of the gravity field for purposes of the attack roll's range increment
penalty, and then add an additional -2 per extra hex traveled to reach the
target. If the attack roll is
successful, the missile will eventually hit the target. If the
target is moving however, it becomes almost impossible to hit it at longer
ranges, because you don't know where it will be when the missile reaches that
range. If the target is in the same
hex, but outside the gravity field, then any missile can reach it right away,
so just use the normal range increment penalty as if the target were at the
edge of your gravity field. If the
target is not in the same hex, impose an additional -8 (for projectile
missiles) or -12 (for thrown missiles) per hex of range to the mobile
target. |
Note that
these missile rules are even more of an abstraction than the normal D&D
combat rules. The movement of
individual missiles across the battle field should probably not be
implemented in any strict fashion. I
strongly recommend letting missiles move their full per-round distance
immediately on the character's initiative, rather than delaying it until
later in the round or just prior to his action next round. I'd also
recommend that you base the number of rounds it takes to reach the target on
the initial range, and disregard any subsequent movement while the missile is
en route, largely because given the stop-and-go nature of how movement is
represented in rounds, I don't think it is worth trying to actually track the
progress of the missile on the battle grid. In the
example, Arnold's axe won't arrive until the following round. It is quite possible that the target
vessel would have moved in between.
Nonetheless, the range penalties involved are intended to take that
into account: the reason Arnold's penalties
were so high is that he was trying to estimate the vessel's motion and throw
the axe to hit where he thinks the vessel will be. |
Note: Do not roll dice to resolve the attack until
the missile actually reaches the destination, because you will still need to
take into account any new circumstances that have occurred in the interim (for
example, applying 100% cover if the target is no longer on the deck of his
ship, etc).
Example: Alain the Archer is on the deck of a
Dragonfly (20' beam). He is at the edge
of the deck, attacking a vessel that is off the port side. Since the gravity field only extends 20' in
that direction, the edge of the gravity field is easily within the first range
increment of his longbow (which is 100').
That means he can attack anything in the same hex without any range
penalty. However, for each additional
hex of range to the target he'll suffer a -8 penalty. The vessel is 2 hexes away, so that is a -16 range penalty, but
his arrow can travel two hexes in the first round, so the attack can be
resolved immediately.
His
buddy, Arnold the Axeman is going to throw a throwing axe at someone else on
that ship. Unfortunately, the range
increment for a throwing axe is only 10', so it automatically imposes a -4 for
two range increments to the end of the gravity field, and then -12 per hex
thereafter, for a total of -28! The
reason that penalty is so high, is because the axe can only travel one hex per
round, so it moves half way right now and won't actually arrive until his initiative
in the next round, at which point the attack roll will be made, so any
additional bonuses or penalties can be included.
As a final
note, this is an ideal situation to use the True Strike spell, since it allows
you to predict where the target will be (ie, the +20 attack bonus offsets at
least a hex or two of range penalties).
If a
character or creature, regardless of size, is attacking a ship, it should be
resolved in a fashion similar to attacks on any other object. Remember that ships, like any object, are
immune to critical hits from normal scale attacks.
To make a
melee attack against a ship, you are most likely standing on (or very near) it,
and given it's size, it counts as an inanimate, immobile object, with an AC of
0. Roll your damage and divide by 10
(round down). Subtract the ship's
Hardness Rating, and apply the remainder to the ship's Structure Points.
A ship
that is unmoving, or is moving but is less than one range increment away, has
an AC of 0. A ship that has a helmsman,
is at least one range increment away, and is moving has an AC equal to its
Evasion Rating. The attack roll suffers
range penalties as described above.
If the
attack succeeds, damage is determined similar to melee attacks. However, in 3e, normal class missile weapons
do half damage against objects. So,
roll the damage and divide by 20 (round down), then subtract the ship's
Hardness Rating, and apply the remainder to the ship's Structure Points.
Objects take
half damage from acid, fire, and lightning attacks. Divide the damage by 20, then subtract the ship's Hardness
Rating, and apply the remainder to the ship's Structure Points. Cold deals one quarter damage to objects, so
divide the damage by 40. Sonic attacks
do full damage to objects, so divide the damage by 10, as per melee attacks.
Spells
that cause damage are generally treated as missile or energy attacks, whichever
seems most appropriate. For example,
Magic Missiles probably count as regular missiles and do 1/20th
damage, while Fireball is a fire energy attack that also does 1/20th
damage, and a Cone of Cold would only do 1/40th damage.
Spells
that don't cause direct damage via force or energy must be handled on a case by
case basis. Spells like Inflict Wounds
will have no affect on most ships, but the DM may optionally allow it to do
1/10th or 1/20th damage to ships constructed of
still-living materials (ie, not dead wood, but possibly the living plants that
are used in Elven ships).
As per the
3e object rules, a ship is considered to always fail its saving throw. Optionally, the DM may allow the ship to
count as being "attended by a character" if there is a helmsman on
the helm, in which case it would use the helmsman's saving throws.
The
effects of some common spells will be covered in my SJ Characters conversion
document (available at my web site).
|
Converting
the original Spelljammer combat rules to the new D&D system is both
fairly straight-forward and also very complex. A number of issues come up due to the change in some of the
basic mechanics. In the
end, I went with a hybrid system that combines some of the best elements
(IMO) from both, but is therefore not 100% compatible with either. One of the decisions that would
have the most impact on the rest of the conversion was whether to use 2e's
Hull Points, Armor Rating, and weapon attack rolls, or change to 3e's
Hardness, Hit Points and random hit system (siege weapons don't have attack
rolls, you just specify where you are aiming and then use the grenade-like
missile system to see how close to the target point you actually hit). I decided I did want to have a
version of Hardness, because it makes sense to me that a small weapon or
glancing strike might damage a wooden ship but not a metal or stone one, for
example. However, if damage resistance is
included in Hardness, then it shouldn't play much (if any) of a role in the
target's Armor Rating, so I decided that Armor Rating just represents whether
the attack connects with the target, kind of like a ranged touch attack. That being the case, it makes no sense to
call it an Armor Rating, so I went with Evasion Rating instead. I decided to stick with 2e's Hull
Points, because in 3e large objects the size of warships would have a lot
of Hit Points, and ship scale weapons would need to roll lots of damage dice,
and with the added step of subtracting hardness before apply damage, it just
seemed like the 3e hit point route would slow things down too much. I renamed Hull Points into Structure
Points, both because it is more accurate and it would get rid of any
confusion between hit points and hull points when using the HP abbreviation. Finally,
I kept attack rolls and the weapon-specific from 2e. 3e siege weapons didn't use level-based
bonuses, so I decided not to either.
Certain feats can give a bonus, but it does not use the weaponeers'
base attack bonuses. |
Normal
scale combat rounds still last six seconds.
Initiative, movement, attacks, attacks of opportunity, etc., are all
resolved as per the normal 3e rules.
Ship scale
actions and combat is divided up into turns.
Each turn lasts one minute and is divided into ten rounds.
Note that
while ship activities are defined in turns, they are often resolved in specific
rounds inside that turn. Rounds almost
become like the old 1st edition AD&D concept of segments within
the turn structure. For example, if a
weapon can fire twice per turn, it will normally get to attack on rounds 1 and
6 of each turn (assuming it started out loaded; otherwise, on rounds 5 and 10).
Within any
given round, any normal character actions are always resolved prior to
resolving ship scale activities. See
the initiative guidelines below.
Given the
slow rate of fire and large distances involved, ship scale combat doesn't
generally allow Attacks of Opportunity.
|
Every
ship, and most creatures native to Wildspace, will have a Speed Rating. The SR represents how fast it can move
when in combat. As per
2e rules, each point of SR means the ship can move one hex per turn (one
minute). A ship with SR 3 can move
three hexes per turn, or 1,500 yards per minute, or just over 50 miles per
hour. However,
that movement is broken up into a series of one-hex moves on different rounds
within that turn. Based upon the SR
of the ship, you consult the following chart to determine on which of the 10
combat rounds in the current turn the ship gets to move a single hex. For example, a vessel that has an SR of 4
can move up to 4 hexes each turn, by moving straight ahead 1 hex in rounds 2,
5, 7 and 9. The
vessel doesn't have to move on every specified round. It can either skip its movement or
"spend" that round's movement on turning in place (see Maneuver
Rating below). However, if it chooses
to skip its movement, it does not get a "bonus" move later. That round's movement is lost for that
entire turn. |
There
were a number of knock-on effects from trying to convert ship movement rates
into the structure of 6 second rounds, which would affect the size of hexes,
cause ships to take up more than one hex each, and shrink the effective size of a hex-covered battle map. That last point, the effects on
the battle map, makes it more difficult to display several ships at once,
conduct long range attacks, or even display enough hexes to let a ship get
out to the 7-mile "escape range". In the end, I decided to keep the
minute-long structure (which I called a turn), but decided to "spread
out" the ship's activities onto different rounds within that turn. The
advantage is that movement and weapon rates of fire is much smoother than in
normal 2e SJ. A ship that has an SR
of 3 moves one hex on three separate rounds, rather than 3 hexes all at once
while other ships just wait for their action. |
||||||||||
|
|
Rounds |
|
|||||||||
|
|
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
|
|
SR 1 |
|
|
|
|
X |
|
|
|
|
|
|
|
SR 2 |
|
|
|
|
X |
|
|
|
X |
|
|
|
SR 3 |
|
X |
|
|
X |
|
|
|
X |
|
|
|
SR 4 |
|
X |
|
|
X |
|
X |
|
X |
|
|
|
SR 5 |
|
X |
|
X |
X |
|
X |
|
X |
|
|
|
SR 6 |
|
X |
|
X |
X |
X |
X |
|
X |
|
|
|
SR 7 |
X |
X |
|
X |
X |
X |
X |
|
X |
|
|
|
SR 8 |
X |
X |
|
X |
X |
X |
X |
|
X |
X |
|
|
SR 9 |
X |
X |
X |
X |
X |
X |
X |
|
X |
X |
|
|
SR 10 |
X |
X |
X |
X |
X |
X |
X |
X |
X |
X |
|
|
SR 11 |
X |
X |
X |
X |
XX |
X |
X |
X |
X |
X |
|
|
SR 12 |
X |
X |
X |
X |
XX |
X |
X |
X |
XX |
X |
|
|
SR 13 |
X |
XX |
X |
X |
XX |
X |
X |
X |
XX |
X |
|
|
SR 14 |
X |
XX |
X |
X |
XX |
X |
XX |
X |
XX |
X |
|
|
SR 15 |
X |
XX |
X |
XX |
|||||||