Spacejammer Combat

By Lindharin
(Lindharin@Telluri.com)

Version 0.92

11/04/00

 

Table of Contents

Introduction

Normal Scale Combat

Zero-Gravity

Spells

Missile Weapons

Attacking a Ship

Ship Scale Combat

How Combat Works

Ship Statistics

Surprise

Initiative

Order of Events

Attack Resolution

Damage Resolution

Special Ship Maneuvers

Notes and Bibliography

 

 

Introduction

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".

Definition of Game Mechanic Terms

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.

 

Normal Scale Combat

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.

Zero-Gravity

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.

Spells

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

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).

Attacking a Ship

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.

Melee 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.

Missile Attacks

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.

Energy Attacks

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

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).

Ship Scale Combat

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.

How Combat Works

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.

Ship Statistics

Speed Rating (SR)

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

XX

X

XX

X

XX

X

 

Note that at speeds over SR 10, the ship can move two hexes in some rounds. Which rounds get the second hex of movement follows the same pattern that started with SR 1.

Maneuver Rating (MR)

Each vessel or creature will be assigned an MR. Based on that rating, it will have certain abilities or restrictions on it's movement at tactical speeds. As per the 3e maneuverability rules in the DMG, the maneuver rating determines how many free hex-face changes it gets per hex of movement, and how far it can turn if it converts a point of SR into maneuvering.

Note that ships which use rigging (almost all of them) have a minimum crew of sailors that is needed to maintain full maneuverability. If the minimum crew is not available, the Maneuver Rating should be reduced 1 rank.

MR

Free Turn

Turn in Place

Pilot Modifier

ER Modifier

A

180 / hex

180 per SR

0

+3

B

90 / hex

90 per SR

-1

+2

C

45 / hex

90 per SR

-2

+2

D

45 / hex

45 per SR

-3

+1

E

0 / hex

45 per SR

-4

+1

F

0 / hex

45 per SR

-5

+0

Free Turn: Ships might get one or more free 45 hex-face changes for each hex it moves. The free turn must be taken after it moves into the new hex. It cannot be taken in the current hex prior to a move.

Turn in Place: On a round when the ship has an available move, it can sacrifice movement to slow down and turn in the current hex. Naturally, this uses up any movement that round and reduces the total distance that can be traveled that turn.

Pilot Modifier: This penalty is applied to the helmsman's piloting skill.

ER Modifier: This is a bonus to ER. It is included in the ship's normal ER, but can be reduced by events that affect MR.

Evasion Rating (ER)

Each ship will have an ER that represents how hard it is to hit the vessel with a ship scale attack. It does not account for the material of the vessel, so it is equivalent to a normal AC against a ranged touch attacks. The ER is primarily based on the ship's size, shape, maneuverability and speed.

The base ER is equal to 10 plus a Size modifier, plus a Design modifier, plus a MR modifier, plus the vessel's maximum SR with the current helmsman.

Note that the SR and MR modifiers only apply when the vessel is mobile and being actively piloted, and the SR modifier must be updated whenever the helmsman changes.

A complete system for calculating HR is included in my ship construction rules (available at my web site). However, as a basic guideline for converting 2e ship stats, use the following chart:

ER by Size

 

ER by Ship Design

 

ER by MR

Tonnage

Size Mod

Design

Design Mod

MR

MR Mod

1-3

-2

Full Enclosure

+2

A

+3

4-10

-3

Partial Enclosure

+1

B

+2

11-20

-4

Standard

0

C

+2

21-30

-5

Partial Expansion

-1

D

+1

31-40

-6

Full Expansion

-2

E

+1

41-50

-7

 

 

F

0

51-60

-8

 

 

 

 

61-100

-9

 

 

 

 

101+

-10

 

 

 

 

Hardness Rating (HR)

Each ship will have an HR that represents the materials from which it is constructed. The HR is subtracted from any ship scale damage prior to that damage being applied to the ship's structure points.

A complete system for calculating HR is included in my ship construction rules (available at my web site), However, as a basic guideline for converting 2e ship stats, use the following chart. If two numbers are listed, use the smaller one if there is just a thin layer of that material over a wooden hull, or the larger one if the hull is made entirely of the material.

2e Saves As

HR

Bone

0

Thin Wood

1

Thick Wood

1

Ceramic

1 or 2

Stone

2 or 3

Metal

2 or 3

Structure Points (SP)

Each ship will have some number of Structure Points. These are similar to the 2e Hull Points. Ten hit points of damage, after subtracting for harness or type of attack (see Normal Class Combat above) correspond to one Structure Point. Note that this does not apply in reverse: weapons that do SP-type damage shouldn't do 10x that to living creatures, for example.

If converting from 2e ship stats, use the same number of SP as the ship had Hull Points. A more complete system of calculating Structure Points based not only on tonnage but also the ship's frame and hull materials is included in my ship construction rules (available at my web site).

 

 

Surprise

Surprise works pretty much the same way it does in the 3e rules. If an enemy teleports onto your ship's deck, resolve surprise normally (ie, he gets a partial action, then roll initiative normally).

When an entire ship's crew is surprised, the situation is similar, but a little more complicated because the effects of surprise last longer.

A ship's crew can be surprised in a number of different ways. The most common is the sudden emergency deceleration from full speed to tactical speed when another gravity source is encountered. This can result in both crews being equally surprised, in which case you can ignore this step. However, if one ship is prepared for the encounter, for example if a pirate ship is laying in wait on a known space lane, then surprise is resolved as shown below. Other surprise situations may occur if your vessel is moving at tactical speeds through an asteroid field, gas clouds, or other regions that might allow an enemy to hide until they are ready to attack.

When the DM determines that surprise occurs, the next step is to decide if it is partial or full surprise. Surprise should normally be considered partial unless there is clear justification otherwise.

When it comes to personal surprise, people can recover in a few seconds (the ambusher gets partial actions).

However, things aren't so easy for an entire ship. If a ship is surprised by a foe who stages an ambush, all of the crew have to recover from their individual surprise, then get to their duty stations, then start trimming the sails, loading the weapons, etc. That all requires a significant amount of time (more than one round).

On the plus side, the helmsman is usually already at his post and can respond much quicker, and ships who fully staff each shift can also respond better.

Full surprise only occurs when the crew is clearly going to be particularly slow to recover from surprise. A vessel that keeps less than 1/3rd the minimum required sailors and weaponeers on duty while the remaining crew members are all below decks asleep or in the mess hall would clearly be a situation where full surprise might be justified. In these situations, the vessel counts as being surprised for a full turn (1 minute) while the crew recovers and then moves to their duty stations. The enemy vessel has one full turn in which to act, while the defending ship suffers the penalties below.

In all other circumstances, surprise should be considered partial, in which case the enemy gets a partial turn. It gets 5 rounds, or half a turn, in which to act while the surprised ship suffers the penalties below. After the 5 rounds, the surprise turn ends, both sides can roll for initiative, and the first regular turn begins.

The penalties to a ship for being surprised include:

1. For the first round only, the helmsman suffers from a regular surprise, so the vessel loses any ER bonus due to speed (SR) or maneuverability (MR), and the helmsman cannot attempt any maneuvers.

2. If the ship uses rigging and Wild Sails, its Maneuver Rating gets one worse, which also reduces ER by 1, and the helmsman is at a -2 on all Maneuver checks.

3. No ship class weapons can be fired.

4. The ship is more vulnerable to critical hits, so there is a +2 bonus to the threat range of any ship class weapons that attack the surprised vessel.

Initiative

At the beginning of an encounter, the Captain of each vessel rolls for his ship's initiative. He rolls 1d20 plus his normal Initiative bonus, but the total is also modified by his Crew Quality (Green = -6, Average = -4, Trained = -2, Crack = 0).

The ship initiative rolls are used to determine the initiative order for both the ships and their crews. For example, if Captain A gets a 20, and Captain B gets a 15, then Ship A will move before Ship B each round, and if there is a boarding action, Crew A can go before Crew B.

Player characters and significant Non-Player Characters are allowed to make their own initiative rolls as per the normal rules, but their personal initiative results apply only to normal scale character actions like melee or ranged combat attacks. They must still use the ship's initiative for ship scale actions like heavy weapon attacks.

To reduce book-keeping, normal 3e rules for modifying initiative (Ready, Delay, Refocus, etc) do not apply to ship or crew activities. PCs and significant NPCs can still use these activities when acting as individuals within a round (for example, in melee combat). If the extra book-keeping is not a problem for some DMs, they can optionally allow ships and individual crew members to use these activities as well.

Order of Events

Beginning of a Turn: Each ship's Captain can issue orders for that ship's course and speed, what targets the ship's weaponeers should aim for, and what type of maneuver(s) the helmsman should use for the upcoming turn (Attack, Defense, or Ram). This is a free action.

Beginning of a Round: Personal activities, like melee or ranged combat and spell casting occur normally. Use the individual initiative order for significant characters, while all others (crewman, marines, etc.) use their ship's initiative.

Middle of a Round: Ship activities take place after all individual actions in that round. Each ship acts in the order of their Captain's initiative roll. For each ship, that ship's activities occur in the following order:

1.

Movement: Based on its SR, the ship may or may not be able to move a hex this round. If a ship is able to move this round, the helmsman can move forward and/or change facing, as per the Movement rules in the Maneuver Rating section above. This is a free action for the helmsman.

2.

Maneuver: If the helmsman did not take any personal actions this round, then he may choose a piloting Maneuver for this round. It should usually be the same type the Captain ordered at the beginning of the turn, but he must use his own judgment as circumstances change. If the chosen Maneuver requires a check, he should make a Profession [SF Pilot] check to see if he succeeds. The Captain or Sailmaster should roll the average Sailor skill to determine if the helmsman gets a bonus or penalty to his maneuver roll (see the Pilot and Sailor skills for details). Any benefits and penalties for the maneuver apply until this phase of the next round.

If the Captain's orders at the beginning of the turn included a ram, and if the ship's movement this round has brought it into the same hex as an enemy vessel, the Helmsman can take the Ram maneuver. Otherwise, that maneuver is not available this round - it would be a suicidal helmsman that rams when none of his own crew are expecting it or prepared for it.

3.

Missile Fire: If a weapon is ready to fire this round, based on it's reload time, it may do so.

End of a Round: If it is round 1-9 within the current turn, go to the beginning of the next round. If this is the end of round 10 within the current turn, continue to the end of the turn.

End of a Turn: Check escape distances, onboard fires, etc., then go to the beginning of the next turn.

Attack Resolution

Assuming at least on member of the weapon's crew has the Shipboard Weapon Proficiency feat, the basic attack roll with any ship scale weapon is 1d20 + Weapon Accuracy - Range Modifier. If not, there is a standard -4 penalty. Some feats, including Weapon Focus, may provide additional bonuses to the attack roll.

Attacks vs. Creatures

The attack is compared to the target's Armor Class, but it counts as a ranged touch attack, so the target's armor, shield and natural armor bonuses do not apply.

However, all ship scale weapons suffer a -4 attack penalty when targeting any living creature; basically this represents the "size modifier" of the weapon (which is not the same as the ship as a whole) and also a creature's ability to react faster than any vessel.

Only the Light Ballista is capable of targeting a specific living creature that is large-sized or smaller. A medium ballista can target a specific creature that his huge-sized. All other ship scale weapons can only be used against targets that are at least gargantuan-sized.

Use the weapon's normal scale Critical rating for the threat range, and resolve it like any other normal critical hit.

Attacks vs. Ships

The attack roll is compared to the target ship's Evasion Rating.

The weapon scores a threat against a ship when the natural unmodified die roll equals or exceeds the ship scale Critical rating for that weapon. The attacker then makes a new attack roll, and if it is also successful then the weapon causes a critical hit to the target vessel (see Damage Resolution below).

Weapon Accuracy

Each type of weapon will have an accuracy bonus (abbreviated as "Acc.") which represents how accurate that type of weapon is.

Range Modifier

Each weapon has a Range Modifier that should be subtracted from the attack roll for each hex of range.

The maximum effective weapon range is the point at which the range penalty exceeds a -20.

For example, a weapon with a Range Mod of -4 is -4 to hit at one hex range, -8 at two hexes, and -12 at three hexes.

Due to the size of hexes, it is difficult to assign range increments in whole hexes. Since there should be several increments inside one hex, that means there will be a penalty larger than -2 per hex. The easiest way to handle this is to just assign to each weapon a penalty per hex. You get the same range penalties as you would in the normal system, but you avoid dealing in fractions of hexes.

Reloading Weapons

Each weapon will have a reload time, which is the number of full-action rounds needed to reload. It does not include the actual firing attempt, so the weapon can fire on the next round after the required reload rounds have been finished. For each weapon crew member that is not available, the reload time increases by 1 round.

Weapon Stats

The basic combat stats for common SJ weapons is included here. More complete information on weapons, including costs and space requirements, is included in my ship construction rules (available on my web site).

 

 

 

 

Range Mod

Ship Scale

Normal Scale

 

Weapon

Crew

Reload

Acc.

Damage

Criticals

Damage

Criticals

Notes

 

 

 

 

 

 

 

 

 

 

Ballista, Light

2

3

+3

-3

1

--

3d8

19 / x2

 

Ballista, Medium

3

4

+3

-3

1d2

20

4d8

20 / x3

 

Ballista, Heavy

4

5

+3

-4

1d4

18

4d10

20 / x3

 

Usually installed on swivel mounts and can fire in most directions.

Light ballistas typically are used as anti-personnel weapons. They are the only ship scale weapon that can target a creature that is less than huge-sized.

 

 

 

 

 

 

 

 

 

 

Catapult, Light

3

4

+0

-4

1d4

20

4d8

20 / x2

 

Catapult, Medium

4

6

+0

-5

1d6

18

4d10

20 / x2

 

Catapult, Heavy

5

8

+0

-6

2d4

16

4d12

20 / x2

 

Fixed in place, it can fire in one direction only. Side-mounted catapults can attack to either side of a ship if the helm is manned and the ship rotates on its long axis to bring the weapon to bear.

Catapults can be loaded with shot, in which case it counts as a Jettison (but still needs the full crew).

 

 

 

 

 

 

 

 

 

 

Jettison, Light

2

4

+1

-6

--

--

1d10

--

5' radius, DC 18

Jettison, Medium

3

6

+2

-8

--

--

2d8

--

10' radius, DC 15

Jettison, Heavy

4

8

+3

-10

--

--

2d10

--

15' radius, DC 12

A successful attack hits a random deck location, and everyone in the area gets a Reflex save for no damage. The weapon chief can chose a specific location, but suffers a -4 penalty on his attack roll.

Fixed in place, it can fire in one direction only. Side-mounted jettisons can attack to either side of a ship if the helm is manned and the ship rotates on its long axis to bring the weapon to bear.

 

 

 

 

 

 

 

 

 

 

Bombard

3

6

+1

-5

1d12

16

4d10

20 / x3

 

Fixed in place, it can fire in one direction only. Side-mounted bombards can attack to either side of a ship if the helm is manned and the ship rotates on its long axis to bring the weapon to bear.

Each shot uses 10 charges of smokepowder. Smokepowder works in some Crystal Spheres but not all.

Any critical hit the ship takes has a 5% of igniting the powder magazine. The powder magazine is also known to rarely explode while traveling through the phlogiston.

 

 

 

 

 

 

 

 

 

 

Greek Fire Projector

3

8

+2

--

1d4

20

3d10

19 / x2

5' radius, DC 15

Damages both the target ship and possible crew. A successful attack does damage to the ship, and has a 50% of hitting an exposed deck area. If the deck is hit, randomly determine the location, and everyone in the area takes the normal scale damage, with a Reflex save for half. Alternatively, the weapon chief can chose a specific location, but suffers a -4 penalty on his attack roll.

Vessels with an outer surface (hull or plating) of wood do not get to use their HR. Greek fire starts fires where it hits, even on stone or treated wood, and spreads normally if the surface is flammable.

Greek fire can only be projected to another ship if the air envelopes overlap.

Any critical hit the ship takes has a 5% per projector of causing an addition Fire critical effect.

 

 

 

 

 

 

 

 

 

 

Sweeper, Gnomish

3

8

+2

-6

--

--

1d10

--

10' square

Still experimental, made of two light ballistas on a single mount that fire a heavy chain (like a giant bola).

A successful attack hits a random deck location, and everyone in the area gets a Reflex save for no damage. The weapon chief can chose a specific location, but suffers a -4 penalty on his attack roll.

Unless stopped by a Large-sized or immovable object, it continues into the next 10' square area away from the firing ship. It can only affect a maximum of two 10' squares.

Everyone in the area must also check to see if they fall, as per a Ship Shaken critical effect.

Damage Resolution

Each ship scale weapon has two damage ratings, one for use when it hits a ship scale target, like another ship, and a second damage rating for when it hits a living creature or smaller object.

Damage vs. Creatures

On a successful hit, roll damage as indicated in the Normal Scale section of the weapon table. Critical hits are resolved as per normal combat, usually doing x2 or x3 damage.

Damage vs. Ships

On a successful hit, the attacker rolls the weapon's Ship Scale damage dice, subtracts the target's hardness rating, and applies the remainder to the ship's structure points.

Ship scale weapons can cause critical hits, much like in normal class combat. However, instead of just increasing the damage, a critical hit against another ship results in a random special effect, as defined below.

In addition, when a ship's structure points are reduced to one half it's normal maximum, the ship immediately suffers a critical hit.

When a ship's structure points are reduced to 0, it is literally coming apart at the seams and immediately suffers another critical hit. Roll 1d6 for every 10 tons of the ship (rounded up) to determine the number of large, atmosphere-retaining pieces of the ship.

Critical Hits on Ships

On a successful critical hit, the weapon does its normal damage to the enemy ship and also requires a roll on the Critical Hit table below.

Note that other events (ramming, some spells, turbulence, etc.) can also cause critical hits. A vessel also automatically takes a critical hit when it is either reduced to 50% of its structure points or reaches 0 structure points. Note that, since some critical hits reduce the ship's hit points, there can be a short cascading of critical hits in this manner.

When a critical hit occurs the result is determined by rolling 1d20 on the following chart:

1

Loss of 5 SP

The target takes 5 extra structure points.

2

Deck Crew Casualty

The ship takes the normal rolled damage. In addition, the shot hits near a crewman who is on deck (selected randomly), and either directly or indirectly causes its regular normal-class damage to that character and half damage to any others within 5' of the target location. Everyone in the area is allowed a Reflex save (DC 10) for half the indicated damage.

If there are no crew members on deck, the ship takes double damage (after subtracting its hardness).

3

Crew Casualty

The ship takes the normal rolled damage. In addition, the shot either directly or indirectly causes its regular normal-class damage to any one character (determined randomly) anywhere in the vessel, as well as doing half damage to any other characters within 5' of him. Everyone in the area is allowed a Reflex save (DC 10) for half the indicated damage.

Depending on circumstances, this may represent effects of the missile itself or merely shattered parts of the ship's interior bouncing around.

4

Ship Shaken

All characters who are not sitting or firmly braced have a chance to fall to the deck, which cancels any actions until they stand up again. Each character may attempt a Balance proficiency check against a DC of 10 to avoid the fall. The DM can assume most ship-board NPCs have at least a +2 bonus on this roll, but that approximately 40% will fall.

5

Large Weapon Damaged

One large weapon (chosen randomly) is inoperable until repaired. Its crew must make a Reflex save (DC 10) or take 1d10 damage.

6

Deck Crew Casualty

As above.

7

Hull Holed

This attack punches a hole in the ship where there was none before. The DM chooses which part of the ship is holed, either randomly, or according to the positions of the ships, or wherever would make things most interesting at that point. Any characters within 10' of the impact point must make a Reflex save (DC 10) or take 1d10 damage from debris.

8

Maneuverability Loss

The ship drops one MR for 1d10 turns, which may reduce the ER by 1.

9

Loss of 10 SP

The target takes 10 extra points of damage.

10

Ship Shaken

As above.

11

Fire!

A fire starts somewhere in the ship, determined by the DM. If it is impossible for a fire to start (no torches, lanterns, cooking fires, and no flammable materials that might ignite by a quick spark), go to the next entry.

If a fire starts in this fashion, and doesn't cause an explosion of some sort (say, if smokepowder was the culprit) it does no damage this turn but spreads as per the normal rules for fire, starting with a size of 1.

12

Loss of SR

The maximum SR of the ship drops by 1 point for the next 1d10 rounds. This can be cumulative, so any additional critical hits with this result increase the SR penalty and increase the remaining duration. If a ship with SR 1 gets this result, go to the next entry. Remember that each drop in SR also causes a -1 penalty to ER.

13

Deck Crew Casualty

As above.

14

Large Weapon Damaged

As above.

15

Ship Shaken

As above.

16

Hull Holed

As above.

17

Maneuverability Loss

As above.

18

Loss of SR

As above.

19

Spacejammer Shock!

The helmsman must make a Will save (DC 10) or fall unconscious for 1d4 hours. If failed, he must then make a Fortitude save (DC 10) or it turns into a coma that lasts 1d4 days! In the case of Series Helms, each creature in the series must save.

20

Roll twice.

Ignore this roll but roll on this table two more times.

Special Ship Maneuvers

Ramming

When ramming, the helmsman's attack roll is a Profession [SJ Pilot] check (1d20 + Pilot skill), modified by the ship's Piloting Penalty (if any). It is compared to the target's Evasion Rating. If the defending ship's helmsman is using an Evade Ram maneuver, his Pilot skill is added to his ships ER for purposes of resolving the ram only. If a hit is scored, damage and other effects depend on the type of ram used.

Caution must be used when ramming. Ramming another ship head-on may increase your damage because your combined speeds are used for calculating damage, but it also expose your ship to the target's ram (if it has one). Also, ships that attempt to ram vessels more then three times their size in tonnage, or vessels that attempt to ram without actually having a reinforced ram on their ship, actually count as being in a "crash" instead. The crashing ship usually takes a great deal damage, though it might inflict significant damage on the target as well.

Blunt Rams: Damage is the attacker's SJ tonnage / 10 * Effective Speed (round the final result down). Effective Speed is usually the attacker's SR, but it can vary according to situation. For instance, if ramming a fleeing vessel from the rear the Effective Speed will be less then if the two vessels were colliding head on.

In addition, blunt rams result in an automatic Ship Shaken critical hit, and one other critical hit that is randomly rolled.

Piercing Rams: Damage is the attacker's SJ tonnage / 20 * Effective Speed (round the final result down). Effective Speed is usually the attacker's SR, but it can vary according to situation. For instance, if ramming a fleeing vessel from the rear the Effective Speed will be less then if the two vessels were colliding head on.

Piercing rams result in both a Hull Holed and Ship Shaken critical hit, plus one other critical hit that is randomly rolled.

There is also a chance that the two ships will become locked together. The chance is 5% times the target's tonnage. They count as being grappled until a helmsman successfully pulls them apart with a Profession[SJ Pilot] skill check. The ramming helmsman has a DC of 20 to withdraw the ram because it is only moderately difficult to back straight out, but the target ship's helmsman has a DC of 25 to maneuver off the ram.

Grappling Rams: These rams inflict 1 point damage times the Effective Speed of the attacking ship. Effective Speed is usually up to the attacker, and can be as low as 0 or as high as their SR. However, it can vary according to situation. For instance, trying to grapple a ship that is moving in your direction will usually have at least its SR as an effective speed.

Grappling rams also result in an automatic Ship Shaken critical hit, and the two ships are considered Grappled.

Shearing

Ships that are equipped with piercing rams or shearing blades may attempt to shear away the rigging of opposing vessels. This is treated as a ram attack, except no damage is done. Instead, for each successful shear attack the target's Wild Sails and rigging are damaged.

Ships with Topped Out rigging get reduced to Standard, which results in -1 SR and -1 MR. This might cause an effective -1 or -2 ER (from the SR/MR losses) and a -1 on Piloting skill checks due to the reduced MR.

Ships with Standard rigging (or Topped Out rigging that has already been sheared once) get reduced to Minimal, which results in a -1 SR and therefore an effective -1 to ER. If the ship does not have a helm that provides motive power, it is now dead in space until repairs can be made.

Ships with Minimal rigging get reduced to No rigging, which results in a -1 MR. This might cause an effective -1 ER, and a -1 on Piloting skill checks due to the reduced MR.

Grappling

Two ships can become grappled in several ways, most often either a result of a ram or the use of grappling tools like long hooked poles, ropes with grappling hooks, ballista bolts with ropes attached, etc. Use the rules for ramming (above) in the first case. However, if the crew of a ship is attempting to grapple another ship using hooks, ropes, poles, and similar tactics, use the following rules:

The relative speed difference between vessels cannot be more then 1 SR when attempting to grapple.

The attacking ship must move into (or already be in) the same hex as the target, and the helmsman must use the Grapple maneuver for his Profession[SJ Pilot] skill check in order to move his vessel close enough to the target.

If the helmsman is successful, the rest of the crew can begin their attempts to grapple. If both ship's crews wish to grapple the attempt is automatically successful. If not, then ballistas armed with grappling bolts can be launched during the ship's Missile Fire phase that same round. Alternatively, on the following round (if the target hasn't moved out of range), any crew who are attempting to use grappling poles or hooks on ropes can attempt an attack roll against an AC of 10. Use of poles counts gets any appropriate melee attack bonuses, while throwing grappling hooks and ropes counts as a ranged attack.

On the next round after a successful grapple attempt, the crew can automatically pull the other vessel into contact if there are sufficient ropes/poles are connecting the two vessels. At least one such grappling tool must have successfully grappled the target ship for every 10 tons of the smaller ship. For example, if a 50-ton vessel is next to a 30-ton vessel, whichever crew is attempting the grapple needs a minimum of 3 successful grappling hits in order to automatically complete the grapple on the following round.

Breaking the grapple is automatic if both vessels desire it. Otherwise the defender must somehow manage to reduce the number of grappling tools below the required number of one per 10 tons of the smaller vessel. Cutting the thick ropes typically used for grappling requires an attack roll against an AC of 7 and at least 4 points of damage. Grappling poles are AC 7, with a hardness of 5 and 5 hit points. Grappling chains are AC 7, hardness 10, and 5 hit points. Alternatively, a Strength check against a DC 15 can pry the hook itself loose, but it leaves the grappling tool intact and it can be used again if there are still crew members able to try again on the other ship.

Notes and Bibliography

The above document contains TSR trademarked material, as well as paraphrased copyrighted material. This document is not intended to challenge that status.

Bibliography

TSR / Wizards of the Coast

The core rules and setting for the Spelljammer game were produced by TSR in the early 1990s. TSR was subsequently bought by Wizards of the Coast. All Spelljammer intellectual properties are copyrighted by Wizards of the Coast.

Similarly, AD&D 2nd Edition (which is referred to as 2e) and D&D (referred to as 3rd edition or 3e) are also copyrighted by Wizards of the Coast.

Spelljammer-L Mailing List (SJML)

The Spelljammer-L mailing list is one major source for ideas and online community within the Spelljammer game. A number of ideas in this document are based on discussions from the mailing list. For more information, check out the Official Spelljammer web page.

URL: http://www.darkwood.cx/rpg/compendium/

Eric Thornber

Some of the ship combat rules and descriptive text, and a few skill ideas, were taken from Eric's conversion rules for D&D, which is available at his web site.

URL: http://www.pave-france.org/~didymus/sj/

Leroy Van Camp

The ship design ideas are strongly based upon Leroy's "Spelljammer Ship System", which is available at his web page, the Tarkas Brain Lab IV. Other miscellaneous ideas from Leroy include some of the skills and ship combat modifications, but they came from his posts on the SJML.

URL: http://www.users.qwest.net/~malacoda/TarkasBrainLabIV.html

Andrew Tiffany

Andrew provided some ideas for using 3e's Hardness and Hit Point system for objects instead of the 2e Hull Points. These ideas were from the SJML.