Welcome to the Spelljammer's Logbook

Well... kind of. This is a smaller excerpt of the full Spelljammer's Logbook that I gave to my players to start my spelljammer campaign that covers the entire solar system and setting for that campaign. I have trimmed this version down just to cover how I handle wildspace travel, ship movement and combat, and the roles of your players on those ships. I have also done my best to add in notes explaining why I made some of the decisions I did. Since the original document was intended for my own personal use with my group I almost certainly will miss something so feel free to reach out if you have any questions. In addition, since this was never intended to be a public document, none of the art is mine and none is properly cited, its just cool art I wanted to use; I also borrowed heavily in parts from other homebrew.

A second note should be addressed: I have only played with 5th Edition. I have no experience with the prior systems, ship combat systems, or spelljammer in general other than a bit of searching around online here and there. My players just wanted me to run a spelljammer campaign so I made this. I apologize in advance if my definitions or handling of things are off from what you expect. Now that I've gotten that all done with, I hope this serves as a good resource for you to use and bend to your own uses and I hope you enjoy D&D space exploration as much as my table has. Now all of that is out of the way, lets get into it.

Imagine a universe where square worlds spin around gemstone suns. Where planets lie cradled in the roots of an oak tree so vast its leaves twirl around brightly burning stars. Where ships of wood, stone, and metal sail the void between worlds and do battle with catapult and ballista, spell and sword, where an asteroid may be a safe harbor, a slaver's den, or a hungry creature eager to devour any that pass by. Where daring swashbucklers and scoundrels race for fantastic treasures and literally touch the stars. Where terrifying beasts with the power to destroy whole planets roam. Welcome . . . to Spelljammer!

  In this setting, the fantastic is possible and one is limited only by the depths of their imagination. Sailing ships, enwrapped in bubbles of air, travel empty wildspace, moved by the power of their mystic Helms. Gravity is a matter of convenience, where a crew of adventurers can tour the bottom of their ship, and worlds come in all shapes and sizes.

Whole solar systems are surrounded by colossal spheres made of an unbreakable, crystal-like substance to protect them from an ocean of swirling light and color, the flammable Phlogiston, which divides the void between stars.

Terms Every Spelljammer Should Know

From the Crystal Spheres housing isolated bits and pieces of the galaxy and the Phlogiston in which they float down to parts of the vessels you will be piloting through the wildspace within those spheres, there will be a stack of new terms that will look unfamiliar to you that are necessary to define and go over in order to play a whole campaign in this setting.

While what comes in the pages ahead may feel overwhelming as reading material just for a new campaign, many of the terms for wildspace and ship parts only come up if people are uniquely interested in them or there are specific in-game scenarios. Use this more as a reference than something to memorize. The actual combat rules and roles are far more important to keep track of.

Phlogiston [flōjistôn]

  Almost always referred to as The Flow or just Flow because of its unwieldy pronunciation due to its Primordial roots, The Flow is what encompasses crystal spheres. Many accounts and teachings of The Flow describe it as a river on which crystal spheres bob and weave between one another. While this is an incomplete description of The Flow, it captures most of the important parts for any looking for general knowledge about The Flow:

Crystal spheres do seem to be only partially submerged in the flow and move somewhat erratically like a ball bobbing on the waves of a river. They also tend to stay generally near other crystal spheres like multiple balls carried on the same current.

Learned scholars who have devoted centuries to studying The Flow might have more theories on what lies beyond The Flow and how crystal spheres might be a part of larger patterns within The Flow beyond a simple description of a current, but that lies far beyond the scope of this definition.

While much remains a mystery about The Flow, a few things are known to great certainty:

• It is highly flammable, but will not support sustained burning
• It is viscous and has a higher viscosity when pressure is put upon it
• It cannot exist inside of crystal spheres or other Planes. Any attempts to leave The Flow with some of its liquid succeed, but upon arrival The Flow that was captured will have disappeared.
• It is a bright mixture of colors that constantly swirl around one another.

Spelljammer ships require a number of accommodations to allow travel through the inhospitable nature of wildspace. This section delves into the types of spelljammer ships there are, how they are operated, their stats in combat, and defines the different elements that makes up a ship.

Ship Terms

The following terms cover both the terms used to tell parts and directions on the ship as well as the terms used for that stats of a ship in combat. Note that while traditional nautical terms are used as the first spelljammer sailors were sailors on ships of sail, spelljammer ships are not restricted to the same dimensions as normal ships, allowing them to be all shapes and sizes. This means that in some circumstances the specifics of some definitions are used more generally than typical nautical definitions.

General sailing terms

• Port: Left in relation to the ship's bow
• Starboard: Right in relation to the ship's bow

• Bow: The front of the ship
• Stem: The extreme front of the ship
• Port Bow: The front-left section of the ship
• Starboard Bow: The front-right section of the ship
• Beam: The widest part of the ship
• Port Beam: The left-middle side of the ship
• Starboard Beam: The right-middle side of the ship
• Stern: The rear of the ship
• Port Quarter: The back-left section of the ship
• Starboard Quarter: The back-right section of the ship
• Forwards: The direction of the ship's bow
• Aft: The direction opposite of the ship's bow
• Athwartships: Across the ship from side to side
• Amidships: The center of a ship
• Inboard: The direction towards the center of the ship
• Outboard: The direction towards the sides of the ship
• Astarboard: The direction towards the starboard side of the ship
• Aport: The direction towards the port side of the ship
• Astern: The direction towards the rear the ship
• Forward: The direction towards the front of the ship

Locations on a ship

• Deck: A "floor" on the ship
• Main Deck: The largest deck on a ship, often exposed to the open air and extends from stem to stern
• Forecastle Deck: A partial deck above the main deck at or near the bow of the ship, can simply be referred to as forecastle
• Upper Deck: A partial deck above the main deck at or near amidships
• Poop Deck: A partial deck above the main deck at or near the stern of the ship
• Quarterdeck: A partial deck or portion of the main deck where the ship's Helm is
• Lower Decks: Decks below the main deck. Each deck below the main deck is named "second deck" for the first deck below the main one, "third deck" for the deck below the second, and so on
• Cathead: A small area of the ship that juts out, often on the bow of the ship, used to release and draw in the anchor
• Bowspirit: A spar or small area extending on bow of a ship on which ropes from the sails are attached
• Mizzen Mast: The aftmost mast
• Main Mast: The principal mast on a ship, typically the second mast
• Fore Mast: The foremost mast
• Other Masts: While some spelljammer ships have solis sails, it is rare for them to have more than the three masts already mentioned

Ship's Elements

A spelljammer ship's elements are what makes it move, gives it breathable air, and a number of other necessary functions that allow ships to operate in wildspace.

Ship stats

Similar to creatures, ships have an armor class, hitpoints and a number of other stats that are specific to ships.

• Damage Threshold: Whenever a ship would take damage it reduces any damage taken by its damage threshold. Sometimes a ship will have exceptions to this rule such as fire damage bypassing the damage threshold on a wooden ship. You can think of this like hacking at the hull of a ship with a dagger: the damage might leave superficial scarring, but won't affect the ship's ability to function.
• Hitpoints: Ships have hitpoints that work the same as usual. Ships do not count as constructs and cannot be healed by normal means.
• Size: Ships have sizes similar to creatures, but with different dimensions. See the table on the next page.
• Structural Damage: When a ship drops below 2/3 of its maximum hitpoints, 1/3 of its maximum hitpoints, and when it takes a single instance of damage equal to or greater than 1/4 of its maximum hitpoints it takes an instance of structural damage. Certain other effects such as crashing can cause Structural Damage. When a ship reaches 5 instances of Structural Damage it is reduced to 0 hitpoints. When a ship takes an instance of Structural Damage, it must roll a d10 and be affected by the effects in the following table:

Clarification

Some things are easier to explain later during the parts where the helmsman can control and move the ship during combat (such as Turn Amount). Also, every ship is different: make ships with resistances, give helms minor enchantments, add hit die for additional structures built on a spelljammer vessel, and so on. Structural Damage Thresholds are based off of the ship's health.

The RNG

To help here is an example spelljammer vessel: The Raucous Nibbly Goblintown. The RNG is a small vessel that is home to a small village of goblins. This small vessel is formed by an approximately 40 foot wide and 40 foot long slab of stone that is 20 feet deep. Upon this stone, a helm and ship's elements have been attached, allowing it to fly as a spelljammer vessel.

Within the stone are small carved out caverns and a stilted village of small huts rise up nearly 40 feet above the surface of the stone. While this places The RNG nearly 10 feet outside of the 50ft by 50ft restrictions for a small ship, those places are few and far between so this vessel will use the base statistics for a small ship, but add one hit die for the extra mass.

Though the base of The RNG is made of stone, which would generally make it hard to hit, the rest of the stilted structure above is still a part of the ship and much easier to hit, due to this The RNG still uses the base AC for a small ship. If its residents ever decided to redo and outfit the upper structures with more stable and armored creations, they could achieve a higher AC.

The RNG has been outfitted with a number of slime slings, a signum device, an arboretal helm and a pondus gem.

• Arboretal Helm: The helm fixed on top of the stone slab radiates warm, moist air to a distance of 120 feet from it while in wildspace. Once per day as an action the helmsman can cause rain to fall throughout this space. Any liquid that falls or flows out of the helm's atmosphere vanishes upon doing so. When using this ability the helmsman can choose to make the rain made of one of the following substances: water, putrid swamp water, moss slime, or mayonnaise.
• Family Helm: It only takes an action to attune to The RNG's helm.
• Pondus Gem: The pondus gem for The RNG is attuned to both the helm of the vessel as well as the stone slab the helm is fixed upon. So long as a creature makes contact with the stone slab, gravity will pull them towards the surface of the slab. Otherwise the area filled by the atmosphere of the helm pulls creatures down throughout that area.
• Slime Covered: Thick slime and moss covers most surfaces of The RNG, providing protection against fire for the parts of the vessel that are not immune to fire. Whenever The RNG would take fire damage roll 1d4. On a 4 the vessel takes no damage. On a 1-3 the vessel is resistant to the damage.
• Stone Strong: Whenever The RNG would take any damage roll 1d4. On a 4 the vessel doubles its Damage Threshold from 6 to 12 as the damage strikes the hard slab of stone.

Celestial Navigation

Navigating through wildspace can be a daunting task without roads or even land to follow. You won't need to know the specifics of how charts are laid out for different areas of wildspace other than how long it will take you to get from one celestial body to another and how spelljammer vessels operate.

Ship Roles

Every ship has a number of roles necessary to be filled in order to successfully operate while underway and in battle. Some passive abilities will naturally make you better at certain roles on the ship and as you level up you will be able to allocate points towards proficiency in roles of your choosing.

There are five levels of proficiency you can have in each role: Green, Novice, Intermediate, Advanced, and Expert. Green means you have little to no on the job experience and sometimes you simply are good at skills used in that role. Novice means you have experience, but it is limited and you struggle with knowing how to handle situations that don't come up day to day. Intermediate means you have standard experience, but still lack expertise in harder tasks. Advanced means you are experienced in your role and few things can trip you up, even under pressure. Expert means you have ran into most problems that can come up in your role through experience and know all of the aspects of your role, inside and out.

You gain 1 role proficiency point that you can apply to any role of your choosing every even level (2nd, 4th, 6th, 8th, etc.).

Cook

Every ship needs a cook since proper rations and balanced meals are necessary for any length of a voyage. Often cooks are among the more favored roles by others due to the fact that solid meals can be some of the only respite given during rough journeys.

Each ship normally has a single active cook, but others can fill in the role as needed. Often cooks assume other roles on the ship in addition to the cook role.

You gain +1 towards your Cook role proficiency if you have proficiency in Brewer's Supplies or Cook's Utensils.

1 (Green)

  Ships Cook: When purchasing rations and supplies you can appropriately buy the necessary food to sustain the ships crew with a healthy and balanced diet. As long as you have adequate spices and flavorings you can make enjoyable meals out of magically created sustenance.

You can prepare a meal for the entire crew in 30 minutes. If you do 1 hour of preparation the next 3 meals you make within 24 hours only take 5 minutes to prepare. A creature that spends at least 10 minutes doing nothing but eating and enjoying a meal you prepared regains 1d10 hitpoints. A creature can only gain this benefit from your food once a day.

2 (Novice)

  Restful Meal: A creature that spends at least 10 minutes doing nothing but eating and enjoying a meal you prepared gains the benefits of a short rest. A creature can only gain this benefit from your food once a day.

Pots and Pans (at least Novice in Gunner required): You are proficient with your cooking implements when using them as improvised weapons. Your utensils deal 1d6 damage and are considered light. The damage type can be bludgeoning, piercing, or slashing damage based on the utensil type.

A utensil can have other properties (finesse, thrown, etc.) depending on the utensil, ask your DM if you have an idea in mind.

3 (Intermediate)

  Antitoxin: A creature that spends at least 10 minutes doing nothing but eating and enjoying a meal you prepared is cured of one poison affecting it. A creature can only gain this benefit from your food once a day.

Bottled Antitoxin (at least Green in Engineer required): You can create one dose of antitoxin during a long rest that can be drank to remove one poison affecting the creature. This dose remains potent until you create another dose this way.

Local Cuisine (at least Novice in Navigator required): You can prepare food similar to the local food at a destination if you know that place or places similar in culture.

4 (Advanced)

  Hearty Meal: A creature that spends at least 10 minutes doing nothing but eating and enjoying a meal you prepared can gain one of the following benefits: They gain the benefit of the spell Gift of Alacrity or they have advantage on Wisdom ability checks for the next 8 hours. You choose which of the two benefits come from the meal when you prepare it. A creature can only gain this benefit from your food once a day.

Consistent Cook: While your ship is out of supplies you can create enough food and water to keep your crew alive as if by the spell Create Food and Water. You can only do this once per day.

5 (Expert)

  Fulfilling Meal: A creature that spends at least 10 minutes doing nothing but eating and enjoying a meal you prepared can increase their current and maximum hitpoints by 1d12 or regain a spent hit die. You choose which of the two benefits come from the meal when you prepare it. A creature who gains maximum hitpoints from this feature keeps that increase for the next 24 hours. A creature can only gain this benefit from your food once a day.

Engineer

The Engineer takes care of the repair and fitting out of the vessel, and examines whether it is sufficiently provided with ropes, pulleys, supplies, and the other rigging that is necessary for a voyage. When fires erupt aboard and the ship has sustained heavy damage, the engineer is the one to turn to.

Each ship can have any number of engineers at a time. During combat Engineers sometimes help other roles and sometimes tend to the ship's status.

You gain +1 towards your Engineer role proficiency for knowing the cantrip mending. You gain +1 towards your Engineer role proficiency if you have proficiency in the skills Investigation or Survival.

First Mate

The force of personality necessary to hold together an unruly bunch of scallywags, the First Mate handles the crew in the best of times and the worst of times. A First Mate's duties include overseeing the health and wellness of the crew, envoys, cargo, and passengers.

Each ship only has one First Mate. While in combat the First Mate helps command the crew and can help with other roles they know.

You gain +1 towards your First Mate role proficiency if you have proficiency in the Deception, Insight, Intimidation, Persuasion or Performance skill. You gain +1 towards your First Mate role proficiency if you have proficiency in any musical instrument.

  Artillery Stock (at least Novice in Gunner required): You know and can accurately recall the strengths and uses of the ship's equipped artillery, the amount of ammunition and types of ammunition, and the intended target of each equipped artillery type (personnel, hull, rigging, etc.).

4 (Advanced)

  Protector of the Crew (at least Advanced in Cook required): Your knowledge of the cook's role allows you to aid in your cook's preparation. You can gather specific ingredients to give to your cook so that they can incorporate those ingredients into their meals. Once a day your cook can prepare a single meal with one of your special ingredients. A crew member that spends at least 10 minutes doing nothing but eating and enjoying that meal gains resistance to a damage type based on the ingredient used. This resistance lasts 1 hour.

 

  Ingredients are as follows: ground black dragon bones for acid, yeti flesh for cold, fire salamander skin for fire, behir tail for lightning, wolf spider flesh for poison, beholder flesh for necrotic, mind flayer tentacles for psychic, ground unicorn horn for radiant, and ground bronze dragon bones for thunder.

Protector of the Crew (at least Advanced in Engineer required): You can cast the spell Life Transference once per day targeting your ship or any of your crew. Once you target your ship or a crew member with this spell you cannot cast this spell on the same target again in this way until you finish a long rest.

Protector of the Crew (at least Advanced in Gunner required): Once per round when one of your crew misses an attack you can use a reaction to allow them to reroll that attack. They must use the new roll.

Protector of the Crew (at least Advanced in Helmsman required): Your helmsman can concentrate on a spell in addition to concentrating on controlling the helm.

Protector of the Crew (at least Advanced in Lookout required): The entirety of your ship is under the effect of the spell Alarm with the audible effect active. Your crew and passengers known to you do not set off the spell's effect.

Protector of the Crew (at least Advanced in Navigator required): Your knowledge of the surrounding areas allows you to keep your crew guarded against extra-planar foes. Your entire crew is under the effects of the spell Protection from Evil and Good, but you can only choose one of the creature types. You must maintain concentration to give your crew this benefit. If you lose concentration on the spell you cannot regain concentration on this effect again until you finish a short or long rest.

In addition you can change the chosen creature type once per week.

Part 2 | Your Role

5 (Expert)

  Inspirational Leader: Whenever you spend a long rest with your crew you can give one of those crew members a point of inspiration. A point of inspiration allows that crew member to reroll an attack roll, ability check, or saving throw of their choice. After rerolling you have to take the new roll.

Ship's Keeper (at least Intermediate in Engineer required): Your ship is under the effect of the spell Death Ward. You can refresh this effect after a long rest on the ship.

Gunner

The Gunner is in charge of maintaining and firing the weapons systems aboard a ship. This includes ensuring that all weapons are kept in good repair. A knowledgeable Gunner is essential to the crew's effective use of the artillery aboard a spelljamming vessel and boarding enemy vessels. Both ships with and without artillery use Gunners to lead boarding missions and protect against enemy boarders.

A ship can have any number of Gunners and any number of active Gunners at a time. Often other crew also fill the role of a Gunner in addition to their other
roles.

You gain +1 towards your Gunner role
proficiency if you have proficiency in
martial weapons. You gain +1 towards
your Gunner role proficiency if you have
proficiency in Athletics or Acrobatics.

Helmsman

                                 The Helmsman is in charge of                                             navigating the ship through                                      spaces unknown. This station is                              required for the ship to continue to travel                               as a Helmsman needs to continue to                                   concentrate on the Helm in order to                  keep the ship moving.                                                               A ship can have any number of Helmsmen,                       but (on all types of Helms except Sequence                          Helms) only a single Helmsman can control                              the ship at a time.

                             You gain +1 towards your Helmsman                                role proficiency if you can cast spells of                  level 1 or higher. You gain +1 towards your Helmsman role proficiency if you have proficiency in Arcana.

3 (Intermediate)

  Helm's Watch: You can attune to a large or smaller Helm in order to control it.

Resistant Helmsman: You have resistance to any psychic damage you take from your Helm.

Quick Return (at least Intermediate in Navigator required): You can cast the spell Dimension Door as long as your destination is your Helm. You cannot cast this spell again in this way until you finish a short or long rest.

Part 2 | Your Role

4 (Advanced)

  Helm's Watch: You can attune to a huge or smaller Helm in order to control it.

Battle-Hardened: You have advantage on saving throws against Helmsman's Shock.

5 (Expert)

  Helm's Watch: You can attune to a gargantuan or smaller Helm in order to control it.

Flexible Control: You can control a Helm as long as you are physically touching the ship that Helm is attached to.

Controlled Destruction (at least Advanced in Engineer required): Halve the damage your ship takes while ramming or crashing.

Lookout

The lookout is a universal job on a ship and almost every crew member takes part in watch to make sure the ship stays on course and stays out of danger. Lookouts will keep watch for debris and ships, take bearings to help navigation and keep track of the the paths of other ships, and monitor the status of the different aspects of the ship.

Each ship can have any number of lookouts at a time and during combat the lookouts assume a separate role to help defend the ship or engage in attacks.

You gain +1 towards your Lookout role proficiency if your passive perception is at least 10, +2 if your passive perception is at least 12, +3 if your passive perception is at least 14, +4 if your passive perception is at least 17, or +5 if your passive perception is at least 20.

Navigator

The Navigator keeps track of ship's charts and plots courses prior to a journey. A good Navigator can determine the location of a ship based on the charts available, knows when to change charts, and knows how to read a number of different charts and coordinate systems. Wildspace is massive and the difference between being a within a few miles and a few feet of your target is a good Navigator.

Each ship needs a Navigator. During combat the Navigator often will take over a separate role, but can offer insight to ship distances and movement options while in combat.

You gain +1 towards your Navigator role proficiency if you have proficiency in Cartographer's Tools. You gain +1 towards your Navigator role proficiency in your have proficiency in Navigator's Tools.

4 (Advanced)

  Careful Planning: When you plan a route with charts that don't exactly match up you can map your route with some accuracy in uncharted territory.

  You can better infer the safest route based on the information present on your charts allowing your ship safer passage.

Unhindered (at least Advanced in Engineer required): You can cast the spell Freedom of Movement. You cannot cast this spell again in this way until you finish a long rest.

5 (Expert)

  Flow Charts: You can, as accurately as possible, plan routes from one Crystal Sphere to another.

Honing In (Expert in Lookout required): You know and can cast the spell Find the Path. When you cast the spell in this way you do not need any materials except the object from the location you wish to find. Once you cast this spell in this way you cannot cast it again for a week.

Deckhand

Deckhands are the standard crew on a ship: handling sails, anchoring, cleaning, doing maintenance, and moving ammunition and cargo.

While deckhands are the face of normal sailing vessels, they are less integral on a spelljammer. Smaller ships may have their crew carry out the responsibilities of a deckhand when necessary without having to fill the role. An exception to this are spelljammers with solis sails which require deckhands to properly handle.

You gain +1 towards your Deckhand role proficiency if you have proficiency in vehicles (water) or vehicles (air).

Captain

The captain of a Spelljamming vessel is less of a role and more of a title. A captain generally fills at least one functional role on the ship, but does not always. Cutthroat crews may choose the best Gunner as their captain while a merchant vessel may have their Navigator keep the title in order to keep the ship on course no matter the cost.

On a ship that is owned by an organization or individual the captain is often an experienced sailor chosen by the ship's owner to have final say over decisions. On a pirate vessel or other ship owned by the crew the captain can be voted in or is the strongest crew member. No matter how the captain is chosen, the captain is assumed to have the final say on major decisions.

It is up to each specific ship if the captain works side by side with her crew or keeps her distance. Either way the captain uses her First Mate to better interface with the crew as only small, tight-knit crews can stay cordial with such a disparity in authority.

A final option for crews that own their own ship is to forgo having a captain and vote on decisions together.

Role Clarification

Any crew member can perform the actions and gain the effects of a Gunner, Engineer, Deckhand, or Lookout if you have proficiency in that role. Only one crew member can fill the role of the Cook, First Mate, Helmsman. or Navigator at a given time. A single crew member can fill more than one role that can only be filled by one crew member. E.g. a single crew member can be both the Cook and the Helmsman as well as filling in as a Gunner.

You do not have to be filling a role in order to use your proficiency in that role to gain an effect. E.g. if you are a Navigator, but not the Helmsman you can still use the Magical Semaphore effect if you have at least Novice proficiency in both the Navigator and Helmsman roles.

Roles are not set in stone and different crew members can designate and swap roles out of combat. After swapping roles any lingering effects from a previous role that is no longer held ends immediately. It is necessary for Helmsmen to swap roles regularly to keep the ship moving at all times, but often a designated Helmsman takes command of the Helm in combat when possible.

Ships in Combat

Ships have their own turn in combat. The different roles you fill allow you to act differently during your turn: firing artillery, moving the ship, and everything in between. The Helmsman role is more involved in the ship's turn than any other crew member, but all roles are necessary to keep a ship well defended and in good condition in combat.

Ships do not roll for initiative, but instead have a set initiative based their size:

Tiny: 25

Small: 20

Medium: 15

Large: 10

Huge: 5

Gargantuan: 0

Engineer

Engineers tend to the ship during battle and try to keep damage to a minimum when things are going well and try to keep the ship from falling apart when things are going poorly.

Quick Repairs: You can make a Survival check to attempt to fix a functional portion of the ship or put out a spreading fire as a bonus action. For fix attempts, the DC depends on the severity of damage and the part of the ship that is damaged. The DC for putting out a fire depends on the state of the fire.

Structural Repairs: You can make a Survival check to try and fix one instance of Structural Damage as an action. You can only make a check like this within a minute of when the structural damage was taken and only once per day. The DC is 30.

Damage Control: Your movement speed is increased by 15 feet this turn as long as all of your movement is taken moving towards a broken element of your ship or fire aboard your ship.

Brace! You prepare the ship for impact. The first time your ship takes an instance of Structural Damage until the start of your next turn you can choose to reroll the die roll on the Structural Damage table if you do not like the outcome of the first roll. You must take the new roll.

Steady! The first time your Helmsman makes a Constitution saving throw to keep concentration or against Spelljammer Shock before the start of your next turn they have advantage on the save.

Hold! You help guard the ship from damage. Until the start of your ship's next turn your ship's Damage Threshold increases by your proficiency bonus. If multiple Engineers take this ship action only the highest bonus is added.

Head Down: Halve any damage you take from the effects rolled on the Structural Damage table in the next round.

First Mate

The first mate normally tends to other roles during combat, but have a number of other abilities to help their crew in dire times.

Hold On! You can make a medicine check to try and stabilize a creature that is in contact with the ship as a bonus action once this turn. You can do this from a range of 30ft.

Lend a Hand: You can take the Help action as a bonus action.

I've Got You: You can immediately stabilize a single creature that is within 5ft. of you and is in contact with the ship as an action.

Marked Strike: The first time you make a successful attack against a target this turn, the next attack against that target made by one of your crewmembers before the start of your next turn has advantage.

Check The Logs: You can sense the direction to an object's location as long as that object is within 1000 feet of you and owned by the ship, a crew member, or a passenger as a free action once this turn. You do not know the distance to this object other than if it is within range or not.

Deckhand

Deckhands can handle the sails during combat as well as handle themselves well when the ship is under duress.

  Tend the Sails: You can tend to your sails, raising (letting them down) or lowering (bringing them up) as need be as an action. Depending on the size of your ship and sails, multiple deckhands may need to take this ship action or it may take multiple turns to gain your desired effect.

Gunner

Gunners are the front line in protecting the ship from attacks and boarders as well as launching attacks against other ships.

Aim! You ready yourself with one of your ship's artillery as an action this turn: the next time you make an attack roll with that artillery before the end of your next turn, you ignore any effect that would give you disadvantage on that attack.

Load! When you load one of your ship's artillery you can use your bonus action to add an additional action of loading for that artillery.

Man The Rails! Creatures that board your ship before your ship's next turn have disadvantage on all attack rolls against you until the start of your next turn.

Boarding: You can leap from your ship towards another ship, making an Athletics or Acrobatics check (your choice) to successfully board the other ship as a bonus action. The distance you can cover depends on the boarding gear your ship is equipped with, but is, at minimum, the distance of your long jump. You do not need a running start to make this leap.

Tactical Movement: You can move up to half of your movement speed while you are still aboard your ship as a bonus action.

After Them! You can move up to half of your movement speed towards any enemy boarders that are aboard your ship as a free action once this turn.

Steady! You can use your reaction to increase your AC by 1 until the beginning of your next turn.

Away: You can stow or sheathe any weapons you are currently wielding as a free action once this turn.

Re-equip: You can draw and equip any weapons on your person or within 5 feet of you as a free action once this turn.

Bloodlust: The next time you make a successful attack with artillery before your next turn you gain a number of temporary hitpoints equal to your Gunner proficiency.

Lookout

Lookouts mostly tend to other duties during combat, but the role has some uses.

Just Checking: You can make any ability check of your choice as a free action once this turn.

Spotter: If you make any perception checks this turn you can add your Lookout proficiency to the roll.

Steady Aim: The next ranged attack you take before your next turn does not have disadvantage for attacking at the long range listed if the weapon you are using has a normal range and a long range.

Spotting Trouble: You gain +1 to all Dexterity saving throws you make before the your next turn.

Over There: You can move up to 10 feet as a free action once this turn.

Navigator

Like Lookouts, the Navigator often tends to other roles in combat, but can give some aid to the Helmsman if needed by providing extra insight or messaging other ships.

This Way: You offer insight in the best path to take to your helmsman, the next time your ship moves it can move an additional 5 feet.

Combat Semaphore: You can send a short message of 5 words/signals or less via semaphore to a ship visible to you as a free action once this turn. You must be aboard your ship to take this action.

Additional Rules for Ships in Combat

General Rules

While all of this is homebrew, I wanted to offer some spells and suggested additional homebrew rules to use with this system. You are free to not use these at all and I do not own any of the new spelljammer books so it is possible there is some overlap between this and any additional spells or rules added for handling wildspace and ship travel.

Not all of the spells I added are directly connected to being on a spelljammer vessel, but many help with ship combat by moving creatures around, starting or putting out fires, or otherwise doing things that may be more impactful in ship combat.

Desert

3rd-level transmutation

• Casting Time: Action
• Range: 60ft
• Components: V, S
• Duration: 1 minute
• Classes: Artificer, Bard, Druid, Sorcerer, Wizard

You turn an area into an inhospitable desert, you choose if it is hot or cold. A 10ft cube at a point you choose within range is sapped of moisture, causing water in that area to disappear and for things that are wet become dry. All living creatures within the area need to make a Constitution saving throw. They take 4d8 necrotic damage on a failed save or half damage on a successful save. The area remains dry and unbearably hot or cold for the duration, depending on which you chose. Nonmagical plants within the spell's area wither and die unless they are naturally well suited to the conditions made by the spell.

Hot: Flammable objects that are not being worn or carried are ignited, in addition a creature that ends its turn in the area is ignited. The target takes 1d10 fire damage at the start of each of their turns until a creature takes an action to douse the fire.

Cold: The spell's are is considered difficult terrain. Creatures that start their turn in the area must make a Constitution saving throw or have their movement speed reduced to 0 until the start of their next turn.

If you cast this spell in the same place every day for 30 days it becomes permanent. This spell has no effect on undead or constructs. This is often used as a place to store things that need to be kept cold on a spelljammer vessel.

At Higher Levels. When you cast this spell using a slot of 5th or 6th level, the cube created by this spell can be up to 20ft. When you cast this spell using a slot of 7th level or above the cube created by this spell can be up to 40ft.

Fabricate Climate

8th-level conjuration

• Casting Time: 16 hours
• Range: 1 mile
• Components: V, S, M (3,000gp worth of emeralds and silk ribbon which the spell consumes)
• Duration: Instantaneous
• Classes: Cleric, Druid, Wizard

You fill a 1000ft radius sphere or a 1600ft cube centered on a point within range with breathable air. You choose the strength and direction of gravity as well as temperature, humidity, pressure, wind, precipitation, and light within the area. Precipitation, creatures, and items fall in the direction of gravity chosen, if any. Creatures and items can be expelled from the area by gravity, but precipitation from this spell dissipates upon leaving the area. While you cast this spell a green light emanates from you towards the point you are centering the spell on that passes through solid objects. In addition all creatures that would be in the spell's area are aware of this spell being cast as well as the location of the point you are centering the spell on.

This spell cannot be dispelled by Dispel Magic.

Gust and Gale

1st-level evocation

• Casting Time: Action
• Range: 5ft
• Components: V, M (glass beads of assorted colors)
• Duration: Instantaneous
• Classes: Druid, Ranger, Sorcerer, Wizard

A burst of wind emanates from you. All creatures within range have to make a Strength saving throw or be pushed 10ft away from you.

MacLerie's Dusting

1st-level transmutation (ritual)

• Casting Time: 1 hour
• Range: Touch
• Components: V, S, M (at least 10 metal coins that add up to a total of at least 1sp which the spell consumes)
• Duration: Instantaneous
• Classes: Artificer, Wizard

Select a nonmagical piece of metal or gem that fits in a 1ft cube, at the end of the spell that item turns to powder or dust of the same material.

MacLerie's Pocket Sand

1st-level conjuration

• Casting Time: Action
• Range: Self
• Components: V, S, M (a pinch of pipe weed and some lint)
• Duration: 8 hours
• Classes: Artificer, Bard, Druid, Wizard

You fill a pocket or small pouch with magical sand this spell produces. You can use the sand as a reaction in the following ways:

Create: When you or an ally within 60ft of you makes an attack or casts a spell that requires stones such as a Hill Giant's Rock attack, the cantrip Magic Stone, loading a catapult, or the spell Animate Objects some of the remaining sand travels to them and transforms into the objects they need. The sand always takes the form of round stones of the required size. These stones disappear when the spell or attack that is using them ends. Once you take this reaction 3 times the spell ends.

Blind: When a creature tries to grapple you or targets you with a melee attack you can throw the remaining sand in your attacker's eyes. Roll a d6 and subtract that from your assailant's ability check or attack roll. This does not work on creatures that cannot be blinded, do not need eyes to see, or are not within 5 feet of you. You can choose to take this reaction after you know the outcome of the original ability check or attack roll. Once you take this reaction the spell ends.

MacLerie's Sandstorm

5th level conjuration

• Casting Time: Action
• Range: 120ft
• Components: V, S, M (a pair of earmuffs and a few pieces of blue-tinted glass)
• Duration: Concentration, 1 minute
• Classes: Druid, Ranger, Sorcerer, Wizard

Until the spell ends, whirling sand spins in a 60ft tall cylinder with a 40ft radius centered on a point you choose within range. There is an eye to the storm that is unaffected by this spell and its effects in a 60ft tall cylinder with a 5ft radius centered on the same point as the storm.

The strength of the storm keeps fog, smoke, and other gases at bay. The area is heavily obscured, and exposed flames in the area are doused. Small or smaller flying creatures or objects can’t pass through the storm. Loose, lightweight materials brought into the storm fly outwards, away from the center.

Arrows, bolts, and other ordinary projectiles launched at targets within the storm or its eye are deflected away and automatically miss if they would pass through the storm. (Boulders hurled by giants or siege engines, and similar projectiles, are unaffected.) Creatures in gaseous form can’t pass through the storm.

The coarse sand and strong winds make the storm difficult terrain. When a creature enters the storm's area for the first time on a turn or starts its turn there, it must make a Strength saving throw. On a failed save, it is lifted 10ft in the air, pushed 5ft towards the outside of the storm, and takes 2d6 bludgeoning damage. A creature that would be lifted above the storm's area from being lifted this way is instead lifted to the top of the storm's area. If a creature pushed this way is pushed out of the storm's area they are flung an additional 10ft from the outside of the storm, and are knocked prone. On a successful save the creature takes half damage, is not lifted or pushed by the storm, and descends 20ft if it is currently being lifted by the storm.

Protective Bubble

3rd-level transmutation (ritual)

• Casting Time: Action
• Range: Self
• Components: S, M (intestines from a beast or humanoid)
• Duration: 24 hours
• Classes: Artificer, Cleric, Druid, Ranger, Sorcerer, Wizard

Air surrounds you and protects you from suffocation. You can breathe normally even if your are underwater, underground or in wildspace. In addition you have advantage on any saving throws you make due to changing pressure.

At Higher Levels: When you cast this spell using a spell slot of 4th level or above, you can target up to five additional willing creatures for each level above 3rd.

The creatures must be within 30 feet of you when you cast the spell.

If you cast this spell at 6th level or above, the creatures affected by this spell are immune to damage from changing pressure.

Pocket of Wildspace

9th-level conjuration

• Casting Time: Action
• Range: 120ft
• Components: V, S, M (a black sapphire worth at least 5,000gp)
• Duration: Concentration, 1 minute
• Classes: Druid, Sorcerer, Warlock, Wizard

You conjure the true essence of the vast unknown, for the duration all air is removed from a 15ft radius sphere centered on a point you choose within range as it is filled with the vacuum of wildspace.

A strong gravitational force emanating wildspace poison pulls on creatures within the sphere. For every 1 foot a creature moves within the sphere, it must spend 4 feet of movement. Any teleportation that starts, ends, or passes through the sphere fails.

The first time a creature enters the sphere or starts its turn within the sphere it must make a Strength saving throw or be pulled towards the center of the sphere. On a failed save the creature is pulled to the unoccupied space closest to the center of the sphere and takes 7d12 force damage as they are crushed by the gravity there. On a successful save the creature takes half damage and is not pulled.

Restorative Shield

1st level abjuration

• Casting Time: Action
• Range: Touch
• Components: V, S
• Duration: 1 round
• Classes: Sorcerer, Warlock, Wizard

You touch an ally with at least 1 hitpoint and give them a number of temporary hitpoints equal to 1d4 + your spellcasting ability modifier.

At the start of your next turn any temporary hitpoints remaining from this spell dissipate as they are absorbed into the target creature, healing them for a number of hitpoints equal to the number of temporary hitpoints absorbed.

At Higher Levels. Increase the number of temporary hitpoints by 1d4 for each level above 1st.

Searing Arc

2nd-level evocation

• Casting Time: Action
• Range: 30ft
• Components: S, M (a candle wick)
• Duration: Concentration, 1 minute
• Classes: Sorcerer, Wizard

A string of fire extends from you to a target and attempts to tether it to you. Make a ranged spell attack. On a hit the targeted creature and all creatures within a 5ft line from you to your target take 2d6 fire damage. The target remains tethered to you as long as it stays within range. Whenever you or your target moves in a way that the tether between you would pass through or end in another creature's space then that creature must make a Dexterity saving throw. The creature takes 1d6 fire damage on a failed save or half as much on a successful save. A creature can only take damage in this way once per round. Flammable objects the tether passes through catch fire.

The creature tethered to you takes 1d6 fire damage at the end of each of its turns.

At Higher Levels. When you cast this spell using a spell slot of 3rd level or above, increase all damage dealt by this spell by 1d6.

Wet/Dry

2nd-level evocation

• Casting Time: Action
• Range: 300ft
• Components: V, S
• Duration: Concentration, 10 minutes
• Classes: Bard, Druid, Ranger, Sorcerer

You alter how moist an area is. Create a 10ft tall cylinder with a 60ft radius at a point you can see within range.

Wet: The area becomes damp. Small exposed flames in the area are doused and stealth checks have disadvantage within the area. In addition, creatures in the area take additional damage from certain elemental types of damage: whenever a creature within the area takes Cold, Lightning, or Poison damage they take an additional 1d4 damage of that type.

Dry: The area becomes dry. Small puddles and objects that are damp become dry and survival checks have disadvantage within the area. In addition, creatures in the area take additional damage from certain elemental types of damage: whenever a creature within the area takes Acid, Fire, or Thunder damage they take an additional 1d4 damage of that type.

At Higher Levels. Increase the additional damage dealt by 1d4 for each level above 2nd.

Feats