Enhanced Spelljammer Ship and Battle Mechanics
Introduction
Hi folks! Wow, it sure has been a while since I updated this blog, but I’ve kept it going since I still get a lot of traffic for some of these articles! I’m glad they’ve acted as a good resource. As for me, I’ve been hard at work getting through mortuary school, and the end is finally in site. I’m hoping to squeeze in more time to work on this blog when I’m finally free of the chains of higher education.
That said, I’ve still been writing on the side between assignments. Sometimes I roll out thousands of words of mechanics for something and realize it’s a resource others may enjoy. Case and point: Spelljammer ships!
My current campaign is on pause because of school as well, but I am running a homebrew Spelljammer campaign. For the uninitiated, Spelljammer is a setting for D&D that takes place in the Astral Sea and, primarily, Wildspace. It’s space piracy, baby, and I was so psyched to dig into the new book for it!
Unfortunately, I was disappointed by the pretty bare-bones mechanics in the book. Nearly everything is automatic. No crew, no real weapon strategy, extremely light boarding mechanics — they leave a lot up to your imagination. I appreciate the flexibility to a degree, but frankly they leave a lot of DMs with very little guidance on what to do. My players and I were looking for something a bit more robust.
So, behold! Below is the mechanics I smashed together for my campaign. Please bear in mind that there is minimal playtesting for these mechanics, however, it’s also just a lot of quantifying things happening on the ship that are otherwise not touched on. I’ve split these into sections, so if you find some things unnecessary for your campaign and others perfect, you can slot out whatever you don’t like! This does build off of the mechanics that are in the book, so I’d still recommend having it as a reference.
Without further ado, here’s some fleshed out mechanics for Spelljammer ships and battles!
Crew
Basic Crew Tasks
All crew members should be able to perform the basic functions of ship navigation and maintenance. Any vaguely mentally capable person can perform these tasks with just a bit of training.
Weapon Operation
Ship Basics (hoisting sails, firing engines, cleaning, tying off lines)
Cleaning and Basic Maintenance
Essential Roles
Any self respecting Spelljammer ship has, at a bare minimum, the following roles filled, Players can give themselves these roles, or assign it to a crew member. Each person can only have one role at a time.
Captain. The unquestioned leader of the ship. Gives orders to all crew members and has the final say on navigation, attack strategies, retreats, and discipline. Even the most democratic ships have a strong captain at the helm to have the final say.
Requirements: Must have Charisma OR Intelligence of at least 13
General Abilities
Leader. The captain has advantage on Persuasion and Intimidation checks with their crew and the crews of other vessels, unless speaking with another Captain. Additionally, they can choose to use Intelligence for these rolls, instead of Charisma.
Thamaturge. While onboard their ship, the Captain can project their voice loud enough for crew members within 200 ft to hear and understand them. This carries over chaotic battles and to all parts of the ship, unless silenced.
Vigilant. The Captain cannot be Surprised.
Combat Abilities
Commanding Presence. Crew members within 30 ft of the captain gain a bonus to Attack Rolls equal to the Captain’s Charisma modifier.
Issue Order. As a Bonus Action on each of the Captain’s turns, he can issue a command to crew members who can hear him. This command must be actionable, such as ‘load the canons’ or ‘prepare for boarding.’ Unless a targeted crew member is indisposed or carrying out a different command first, they will do their best to carry out the most recent command at the beginning of their turn.
Rallying Cry (1/day). As an action, the Captain can issue a rallying command to the crew. All crew members within 120 ft of the Captain gain the effects of Bless for 1 minute, or until the Captain is incapacitated or killed.
Quartermaster. The second in command. Settles disputes between crew members, assists in carrying out the orders of the captain, and is generally respected as a second opinion in decision making. They also typically serve as a Navigator, if there isn’t a separate one on board. Should the Captain be incapacitated or die, the Quartermaster is the next in line to take the role.
Requirements: Charisma OR Intelligence of at least 12
General Abilities
Right Hand. While within 15 ft of the Captain, the Quartermaster shares their Leader and Thamaturge ability.
Second Opinion. When the Captain makes a Charisma, Wisdom, or Intelligence check, the Quartermaster can make the same check, and can replace the Captain’s roll with their own if they choose to.
Combat Abilities
Swift Action. During the first round of combat, the Quartermaster’s speed is doubled.
Hold the Line (1/day) The Quartermaster calls for fortitude during battle. All crew members within 60 ft of the Quartermaster who can hear them gain 10 temporary hit points.
Spelljammer. The ship’s controller who is attuned to the Spelljammer Helm. Steers the ship, navigates around obstacles, and is capable of seeing everything happening on the ship while on the Helm. They are usually the first one to notice approaching enemies or obstacles.
Requirements: Intelligence OR Wisdom of at least 14
General Abilities
Restless. While aboard the ship on which their attuned Spelljammer Helm lies, the Spelljammer only needs to rest for 4 hours to gain the benefits of a Long Rest. Additionally, they can go one additional day without sleep before gaining levels of Exhaustion.
Psychic Link. While on the Spelljammer Helm, the Spelljammer can telepathically communicate with anyone aboard the ship, but only one target per message. They also know the exact location of each allied creature on the ship.
Combat Abilities
To the Wheel! When the Spelljammer rolls initiative, they can choose to instead teleport to the Spelljammer Helm, provided they are within 200 ft of it.
Expedite Weaponry (1/day). The Spelljammer, while upon the Spelljamming Helm, can channel psychic energy into the ship’s weapons, providing them with alternative ammunition. All weapons on the ship become ready to fire, regardless of how many actions have passed, but they deal half the damage.
Secondary Roles
It would be ideal to have these roles filled as well, but they are not essential for the function of the ship:
Outlook. Also called the ‘crow’ in some crews. The Outlook is stationed on the Crow’s Nest or other structure meant for perceiving threats beyond the Spelljammer’s perception. Also, ideally, can track weather patterns and unfurl sails if applicable.
Requirements: Must have a Dexterity or Wisdom of at least 12.
Abilities
Keen Eye. While on a vantage point (at least 15 ft.), the Outlook has advantage on Perception checks. Additionally, they have advantage on Nature checks to detect changes in the wind.
Steady Climber. While aboard the ship, the Outlook has a climbing speed equal to their walking speed.
Vigilant. While at a vantage point (at least 15 ft.), the Outlook cannot be surprised.
Navigator. A role filled when crews are large and the Quartermaster is stretched thin. The Navigator is responsible for charting a safe course, even through the toughest asteroid field.
Requirements: Must have a Wisdom or Intelligence score of at least 12.
Abilities
Map Reader. The Navigator can read any map that is legible, regardless of the languages they know. This does not allow them to read written messages on the map, unless they do know the language.
Course Charter. The Navigator has advantage on checks to discern safe passage through obstacles in the ship’s path, provided they have a clear line of sight.
Spelljammer Link. The Navigator can telepathically communicate with the Spelljammer while both they and the Spelljammer are aboard the ship. When they do, the Captain and the Quartermaster also hear the message.
Engineer. A ship may have multiple Engineers, who serve as maintenance crew for the ship. They are well versed in the ship’s technology, weaponry, and status, and can fix damage to the ship far faster than others.
Requirements: Must be proficient in tinker’s tools, smith’s tools, or carpenter’s tools and have an Intelligence of at least 12.
Abilities
Rapid Repair. Engineers can repair lost hit points to a ship at a rate of 5 hp per hour while the ship is moving, 10 hp per hour when the ship is docked.
Quick Diagnosis. Engineers can identify malfunctioning equipment with a glance, and have advantage on Technology checks to fix the error.
Additional Roles
These are not necessary for the function, nor do they have special abilities, but their presence can enhance crew morale and help with logistics.
Boatswain / Scribe – keeps track of inventory, correspondence, and confers with engineers on ship damage.
Cook – responsible for crew meals and ensuring everyone is well fed.
Doctor / Cleric – assists in healing diseased and injured crewmates.
Gunners – typically remain below deck and maintain the weaponry / stand at the ready to helm the weapons.
Pay
A typical crew member on a Spelljammer ship expects anywhere from 5 sp to 5 gp per day for their services. Depending on recruitment strategies, some are there for the thrill of adventure, or to hitch a ride to a distant star. Make no mistake, though: every single creature on a Spelljammer Ship has a reason for being there, be it coin or quest.
Some roles are much more specialized, and thus have a higher pay expectation:
Captains and Spelljammers are typically paid 50 gp per day.
Quartermasters / Navigators are paid 30 gp a day.
Engineers and Outlooks are paid 20 gp a day.
This is the structure of a ship that is paying, mind. A pirate crew often operates on promises: namely, splitting treasure and spoils among the crew, with more specialized roles getting larger cuts. Pay is on top of feeding, housing, and caring for the health of the crew as well.
A crew needs food and water, as well, especially with the hard work of caring for a ship. It’s important to keep track of rations. One ration, at 5 sp, feeds a single crew member for a day. If the ship employs a chef, they can half the cost of each ration, as a cook can use ingredients much more efficiently.
Morale
A ship can only function with a royal and competent crew. Merchant vessels often have sponsors or internal systems of payment for their crew members. Some ships operate largely off slave labor, while others are dedicated soldiers of a militia of one of the Planes of Existence. Short of prisoners, crews expected to be taken care of.
Morale is not tracked by specific point values, so much as the frequency of good and bad influences. It’s the discretion of the DM when morale becomes too low, or when it exceeds excellence.
Events that Raise Morale
Winning battles against enemy ships or monsters
Regular, well cooked meals
Distributing all treasure that’s found while adventuring fairly
Lending an ear to crew’s worries, assuaging their fears
Pursuing specific goals of crew members
Events that Lower Morale
Losing (or fleeing, depending on crew expectations) battles against enemy ships or monsters
Failing to adequately feed and heal the crew
Poorly distributing (or not distributing at all) treasure
Ignoring concerns of the crew / failing to acquiesce to their pursuits
Tyrannical leadership / frequently pushing crew past their limits
If too many events coincide with low morale, affected crew members may confront the Captain or, at worst, stage a mutiny. Worry not – genuine remorse (or a good enough silver tongue) can often assuage any distress for a time.
Ship Mechanics
Spelljammer Ships are intelligent – many of their functions are automatic, such as maintaining its own gravity field and air bubble. Still, they require a crew and some technical know-how to function in Wildspace. The real test is when Wildspace tries to sink its teeth into fresh meat.
Traveling
It is assumed, while traveling, unless told otherwise, that the crew is helping with the function of the ship to keep it clear and clean and ready for every day at starsea. Crewmates will automatically cycle themselves out for rest during long travel. Much like the ocean on the Material Plane, large stretches of Wildspace and the Astral Sea are free of strife, but savvy sailors are vigilant – peace can change at any moment.
The Spelljammer will typically be at the helm for most hours of travel. The ship can move at different paces and functions depending on need.
Easy. The ship is moving at a very slow pace, ideally for navigating tight asteroid belts or coming into port. A ship moving at this speed can come to a stop at a moment’s notice, and is not moving at a pace conducive to making much travel progress. While in this mode, the ship can only benefit from its flying speed.
Half Sail. A medium speed with half sails, allowing for quicker but careful travel. This speed is used when closing in on large, celestial bodies and around wider obstacles. Consistent travel at this speed results in slow but steady progress. Common for caravans and short distance travel.
Full Sail. A fast speed with full sails, allowing for the quickest travel short of Splitstream. This speed makes it difficult to turn, so it’s ideal that the Spelljammer be at their Helm and available to switch speeds should obstacles be encountered.
Splitstream. A sudden burst from one point to another. This travel can only be initiated by the Spelljammer, and only when zero large celestial bodies block the path. The exact space the Spelljammer wants the ship to appear in must have known coordinates. While in Splitstream, the vessel moves fast enough to travel 100 million miles in 24 hours. The surrounding space shifts into a blur, but everyone on the ship can go about daily tasks without issue.
When the Spelljammer needs rest, they may tag in a second Spelljammer, or, place the ship in Autopilot. A ship in Autopilot moves at Half Sail or Full Sail, and takes the most direct route to the destination the Spelljammer marks. Note, the ship does not take obstacles into account, so it’s ideal for the Spelljammer to remain vigilant and ready to return to the Helm at a moment’s notice. Autopilot can also be used to automatically shift a ship to a friendly port.
Gravity
All Spelljammer vessels have their own gravity fields, which extend roughly to the same diameter as the air bubble (i.e. between 150 to 200 ft, based on vessel size.) This allows crew members and all supplies to remain anchored to the ship. Interestingly, this also causes things dropped from the side of the ship to oscillate around it, unless pushed well past the edges of the gravity’s plane. This can be advantageous for engineers working on ship repairs, as they can rest assured they will drift back toward the ship if they push themselves away from it.
Large objects in Wildspace have their own gravitational pull. It can be assumed that the larger the object is, the stronger its gravity, so a prudent Captain will be mindful of getting too close to strange, massive bodies. Approaching these large bodies slowly, the ship’s gravity plane will automatically adjust to allow for controlled approach.
Air Supply
The air bubble of a Spelljammer vessel is the same size as the gravity plane. As long as creatures stay within the bubble, they can breathe. The air of Wildspace and the Astral Sea is deadly without intervention, such as the Air Bubble spell or a mechanical breathing apparatus. The air supply is automatically restored when the vessel sits in the natural air of a large body for at least 1 hour.
Advanced technology allows air supplies of Spelljammer vessels to last for quite some time. A well-maintenanced, new oxygen mechanism in a new ship can maintain fresh air for three months of travel. However, it’s not uncommon for enemies to target these air supplies during attacks, especially if the attackers don’t need air themselves. Damaged oxygen mechanisms will only be able to hold half the oxygen until they’re repaired. Critically damaged ones will only be able to produce noxious air, breathable but highly uncomfortable, causing all who breathe it to be Poisoned until fresh air is breathed.
A ship reduced to zero hit points and adrift will rapidly leak oxygen, as the gravity field fails to hold it in a vacuum. A recently Adrift vessel maintains its air bubble for roughly one hour before it dissipates entirely.
The oxygen mechanism is typically stored in a ship’s cargo bay with hundreds of tiny piping distributing it throughout the ship.
(AN: The book does not detail a specific oxygen mechanism on the ship and instead denotes that the ship simply generates an oxygen bubble with no specific thing generating it, thus it’s not 100% clear if it can be repaired any other way other than just flying into fresh air.)
Combat
As if eldritch horrors, asteroid fields, black holes, and other obstacles weren’t bad enough, Wildspace is filled with opportunistic adventurers seeking gold and glory or blood and gore – or maybe both, if you’re unlucky enough. A savvy Captain and crew is not foolish enough to think they can make it through the Sea of Stars without a scrap or two.
Smoke Signals
Ships with an active Spelljammer at the helm can detect enemy ships from 1000 ft away, assuming they’re not using a cloaking device of some kind. Ships approaching from a distance should be watched for scrutiny – some of the pirate’s code of the seas has carried over into Wildspace. Many independent ships change the color of their thruster smoke to indicate their ache for a fight.
Grey Smoke. The typical exhaust of any ship. This ship is just passing through.
Blue Smoke. This ship is interested in trade, of either items or information.
Green Smoke. Often accompanied by a flare – this ship is in need of help.
Red Smoke. Red is a warning – this ship will attack if provoked.
Black Smoke. If you’re close enough to see it, prepare for battle.
This is, of course, assuming the ship is polite enough to change their smoke at all – or is using the right color for their intentions.
Initiative
When combat is initiated on ships, it’s locked into side versus side combat. This is to say, a single initiative is rolled for each ship participating in the combat, sharing the roll with the crew. The Spelljammer moves on the ship’s turn, and the crew goes immediately afterward.
The typical range of ship weapons is 500 ft maximum for long range weapons, 250 ft for short range weapons. Ships in active combat can move only at their flying speed unless they are retreating. Repositioning the ship to arm weaponry at the enemy is part of the regular movement of the ship.
The Spelljammer can use the ships Movement, then take one action, which is limited to one of the following:
Burst. The ship may move up to its speed a second time.
Observe. The Spelljammer makes a Perception check.
Scan. The Spelljammer attempts to peer into the defenses of the enemy ship. This is a Spelljammer Dual, and the ships must be within 120 ft of one another. Both Spelljammers roll Technology or Arcana check. If the defending Spelljammer succeeds, nothing is learned. If the attacking Spelljammer succeeds, they learn two of the following traits of the ship:
Equipped weaponry
Current health
Nature of the crew (undead, human, monsters, etc)
Resistances
Location of one piece of Notable Equipment
Position of the Captain
Position of the Spelljammer
Ram. The Spelljammer slams the ship into the other. Roll 1d20 + the Spelljammer’s proficiency bonus against the target’s AC. See Crashing rules.
After the Spelljammer’s movement of the ship, the crew can act. If crew members have been assigned specific roles, they are assumed to be performing those roles (such as operating weapons) unless directed otherwise. All crew members not performing a specific task are considered Deckguard.
The Deckguard may move and take actions available to their character. Acting Deckguard may coordinate with one another to determine who moves first in shared initiative, but the Captain typically moves first. While independent actions could be taken, the crew (and players) can get a little creative here as well, and work together to perform unique actions, limited to their imagination. This is especially helpful when enemy ships are too far to practically target with spells and weapons. Examples include:
Climbing to a high vantage point to spot the actions of the opposing crew
Observing space hazards that can be used to the advantage of the Spelljammer
Preparing actions to take place when the ship is at a closer range
Bolstering allies with magic or otherwise
Coordinating the people you want available for boarding.
Addressing damage or ensuring defenses.
It’s up to DM discretion whether or not an action is possible and, if possible, how it plays out in the game.
Attacking and Damaging Enemy Ships
Every Spelljammer vessel has an Armor Class (AC) and a Damage Threshold (DT). When an attack roll is made, it must beat the AC to hit. However, just because an attack hits doesn’t mean that it does damage. The damage dealt by the attack must exceed the DT of the ship. All damage above the threshold is actually dealt. For example, a gunner shoots the enemy ship with a ballista, succeeding the attack and dealing 30 damage. The DT of the enemy ship is 15, so the ship takes 15 damage.
Ships do not have a means to succeed saving throws, so they automatically fail against spells such as Fireball. A ship is an object, and thus can’t be targeted by any spells that require the target to be a creature. Additionally, all Spelljammer vessels are immune to psychic damage.
The positioning and closeness of the ship determines whether individual crew members can be targeted for attacks. But, in general, it’s impossible to aim at any one crew member of a ship without being at a vantage point or being within 60 ft of the ship.
A ship that’s at half health or lower moves at half its speed, and a ship reduced to 0 hit points is Adrift. An Adrift vessel has a speed of 0, cannot use below-deck weapons, and its DT and AC become 5. The prevailing Spelljammer vessel can do one of three things, determined by the Captain:
Final Blow. Some see this as a mercy. A final cannon shot destroys the vessel for good. Any crew that survive the blast die shortly after from the cold vacuum of space.
Leave. You leave the crew to fend for themselves. Hell, maybe you throw them some spare oxygen. They will remember your name.
Board. The Spelljammer may close the distance to the ship and allow the Deckguard to raid the ship. See Boarding.
Boarding
The quintessential work of pirates and raiders, boarding enemy ships is the main way dastardly adventurers find their riches and become infamous. In order to properly board a ship, a Spelljammer must move within 5 ft of the enemy vessel. This is not possible before the vessel is at least half health, as residual shielding prevents ships from making slow approaches before then. Of course, a Spelljammer could ram into the enemy ship to supersede this, at the risk of compromising their own vessel.
Deckguard could attempt to use independent means to board the enemy ship without their ship needing to get too close, as long as they’re willing to brave the vacuum of space, but they can be very easy to pick off with long range weapons.
As soon as a ship is Boarded, Initiative is rerolled to be between both crews. Crew members may be consolidated into groups to keep initiative from being a million miles long, as many crews have more than 20 crew members. Combat can ensue as it would in any other battle.
The prudent Spelljammer crew searches and kills the Captain of the enemy vessel. When the Captain is killed, many crews will automatically surrender, depending on their temperament. Many still would rather die than be captured. If the enemy Captain is killed but the crew does not automatically surrender, the allied Captain can attempt to call for the surrender of the rest of the crew. Said Captain rolls a Persuasion or Intimidation check, against a DC determined by the DM.
A surrendered crew can be killed or spared and/or recruited, but either way, the loot of the ship is the victor’s for the taking.
Crashing
A spelljammer can run their ship into another object or a creature by moving the ship into the target’s space and making a special attack roll (1d20 + the spelljammer’s proficiency bonus) against the target’s Armor Class. If the attack roll hits, a crash occurs; otherwise, the target moves out of the ship’s path, avoiding the crash. If the DM decides that a crash is unavoidable, no attack roll is necessary, and the crash occurs automatically.
When a spelljamming ship crashes into something that could reasonably damage it, both the ship and the creature or object it struck take bludgeoning damage based on the size of the struck object:
Large – 4d10
Huge – 8d10
Gargantuan – 16d10
If the ship runs into something that doesn’t have hit points (such as a planet or a moon), the damage is applied only to the ship. The ship stops after crashing into a Gargantuan or immovable creature or object; otherwise, the ship can continue moving if it has any movement left, and whatever it struck moves to the nearest unoccupied space that isn’t in the ship’s path.
If two Spelljammer Ships collide, their gravity planes also do. If, after a collision, one ship has more HP than the other, that ship’s gravity plane briefly supersedes the other, pulling unanchored objects toward it, suppressing the other ship’s gravity plane until there’s at least 30 ft between them.
Notable Equipment
Most Spelljammer vessels have all the standard equipment necessary to leave right away, but enterprising Spelljammer crews may want to restock, or, invest in some unique equipment.
Standard Equipment
Oxygen Mechanism – Typically has enough oxygen for 3 months of travel. Extensive and installed in such a way to flow through the entire ship.
Below Deck Weaponry – Typically cannons, with standard cannonballs, but depends on the type of the ship.
Above Deck Weaponry – Typically ballista and mangonels, but depends on the type of ship.
Dingy – A small ship with a localized Air Bubble used to cart as few crew members to a close destination. Can typically hold up to six people, and has toggable air for 1 hour.
Ammunition – for the weaponry, cost dependent on the type of weapon.
Spelljammer Helm – Some say this is the heart of the ship. Required to actually steer it.
Specialty Equipment
Shield Mechanism (2000+ gp) – Adds temporary hit points (THP) to a ship’s health bar. The number of THP depends on the quality of the machine. A base shielding mechanism grants 50 THP.
Chain Shots (50 gp per shot) – Specialized cannonballs that are aimed at the sails of certain Spelljammer ships. Can temporarily reduce the speed of other vessels.
Harpoon Ropes (2000 gp for mechanism, 50 gp per harpoon): Anchored harpoons that specialize in stabbing into and yanking ships toward the shooter. Must exceed the damage threshold to stick. For each turn they remain in a ship’s hull, they pull an enemy ship 20 ft closer. At least two harpoons must be in the hull for the pull to work.
Resistance Enchantment ( 5000 gp per resistance). Added damage resistance to a ship.
