Spelljamming: Spelljammer 5E Conversion



While the original Spelljammer campaign setting opened up an entirely new environment for Dungeons & Dragons, it didn’t actually add a whole lot of new rules or mechanics to the game. The largest section of what it did add involved how you actually got a spelljammer ship to move through Wildspace. These ships didn’t have engines and there was no wind in space.  Spelljammer came up with a clever solution to this problem by introducing spelljamming. Much like the windjammers of our own world were propelled through the oceans by the wind spelljammers are powered through the void of space by spells.

Spelljammer vessels were equipped with a magical device known as a spelljammer helm. This device converted magical energy into momentum which “sails” the ship through space. Much of the mechanics of how a spelljammer helm functioned and how a magic-user interacted with the device can be carried directly over from 2e to 5e. In the original Spelljammer rules any character that could cast spells or had spell-like abilities could operate the device. This list originally included the classes of wizards, priests, bards, paladins, druids and rangers, but is expanded out for 5e to include almost every single class that has access to spell slots. So the Eldritch Knight or the Arcane Trickster can now pilot a spelljammer ship.

The two most common spelljammer helms are the minor helm and the major helm. In the 2e rules each of these helms converted magical energy into  power at a different rate known as the Spelljamming Rating or SR.  An SR of 1 equates to a movement rate of 500 yards (457.2 m) per round.  The minor helm converted at a rate of one SR for each three levels of the caster and the major helms converted at a rate of one SR for each two levels of the caster. For example, a tenth-level wizard operating a major helm could move a ship at an SR of 5, or 2500 yards (2286 m) per round.

The maximum SR rating that could be achieved by the operator assumed that they were well-rested and possessed their full complement of spells. For each spell that they had exhausted the SR dropped by one. The caster was also left unable to cast any magic for a full 24 hours after operating the helm. This often left the party’s wizard or cleric acting as a pilot and nothing else.

I went back and forth with how to convert the operation of a spelljammer helm over from 2e to 5e. Obviously, magic has been altered quite a bit between the two additions and this needs to be reflected in the conversion. Most notably, 5e has spell slots and cantrips where 2e did not. I also wanted to eliminate as much table math as possible. There is also an issue of the definition of a “round” between the two editions which I missed on the first go-around. A round in 2e Spelljammer was one minute versus the six seconds that a round is in 5e. This means that an SR of 1 in 5e grants a speed of 50 yards (45.7 m) per round rather than the 500 yards (457.2 m) per round it granted in 2e. So here we go.


Spelljamming is the means by which a ship moves through the Phlogiston or the void of Wildspace. Although there are many varied ways to accomplish this it is most often done through the use of a spelljammer helm. The majority of ships are equipped with either a major or a minor helm, although larger ships may have both with the minor helm acting as a backup.  The spelljammer helm is a large chair or throne which can be operated by any character class with access to spell slots. The helm draws magic from the character and converts it into energy to move and maneuver a ship. A spelljamming character must remain seated and in full contact with the spelljammer helm during operation.
The movement rate that a ship can attain through the operation of these helms is called the Spelljamming Rating or SR. One SR translates to a movement rate of 50 yards (45.7 m) per tactical round. This rating increases or decreases depending on the type of helm and the spell slot levels available to the operator. However, the SR can never be less than 1.  A major helm allows the spellcaster to move the ship at an SR of their highest available spell slot plus 1. For example, a priest who has a 5th-Level spell slot available can achieve an SR of 6 using a major helm. A minor helm provides a movement rate equal to the caster’s highest spell slot minus two. Consequently, if a spellcaster exhausts spell slots by casting spells the maximum SR they can operate a ship at decreases.
Operating a major or a minor helm drains all remaining spell slots from the spellcaster regardless of the time spent in the helm. This spellcaster is left too exhausted to regain spells until after completing a long rest. Cantrips are not affected by this magical drain nor do they have any impact on the determination of SR.
One additional magical item that can used to power a spelljammer ship is a Crown of Stars. This device is worn on the head of the spellcaster operating the ship.  The crown provides the same SR and spell slot drain as a minor helm, but it allows the wearer to move around while spelljamming.


Unfortunately, this doesn’t eliminate any of the math from figuring out SR, but I think it brings it more in line with 5e magic. Let me know what you think in the comments. I’m eager to know if this makes sense to anyone but me.  For now I’ll be moving on to look at ship combat and armaments.


Top Image “Meeting of the Minds” by Buddy Murphy

6 thoughts on “Spelljamming: Spelljammer 5E Conversion”

  1. The problem with “highest available spell slot” is that you could spend every slot below and that would still work. So it’s too easy to avoid the maximum SR decrease.

    Also, you should switch full 24h to simply a long rest, keep things simple.

    1. For this Spelljammer conversion I like to think of operating the helm as casting a spell. That’s why I used the highest available spell slot. They are essentially casting a spell using their highest slot. The connection to the helm disrupts the magic so much that it erases all other spell ability. This doesn’t affect cantrips because they aren’t memorized or granted just always there. My interpretation of the original Spelljammer rules was that this process was grueling for the operator. The 24 hour rule reflects this by being a more severe penalty than just a long rest.

    1. 500 yards in one round works out to about 150 miles per hour. So max SR is 1500 miles per hour or double the speed of sound. Pretty good for a ship made out of wood or stone.

  2. Thanks so much for this! Looks like it’s on the right track. However:

    A Major Helm gives an SR of Highest Spell Slot (HSS) +1. A Minor Helm gives an SR of HSS -2. Is there specific thinking behind going with -2 instead of -1 (to keep parity with the Major Helm)? Seems easier, unless you were thinking of some specific game balance issue.

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