Spelljammer vessels are a bit of a mystery. One spell turns one chair into a magical artifact that can turn any ship over one ton. What constitutes a ship? Why are some faster than others? Does making one with an integrated Treant cost more or less? There aren’t a lot of easy answers here, but I did some digging and I think I found a few.
I spent a lot longer than is reasonable crunching the numbers. I tried to take the dimensions of the vessel into account; that was a dead end. After running the numbers a few different ways, and filtering to the vessels that were most comparable, I found a relationship between the sum of a given ship’s Hit Points, and cargo carrying capacity. I then went back and applied modifiers to the other ships based upon traits listed in their descriptions that bring their speed in line with other ships.
Here in the first table, you can see the values I used to compare the various spelljamming vessels.
|Ship||Hit Points||Speed (ft)||Cargo||HP+Cargo||Note||Mod||SJ Weight||Cost|
|Star Moth||400||50||30||430||Ceramic Hull, Adv. SJH||-170||260||40000|
|Bombard||300||35||150||450||Advanced SJH, Gith Reinforced Hull||-20||430||50000|
Making a Spelljammer: Traits
Next, we look at the traits assigned to a vessel and a modifier alter the sum of HP and Cargo.
|Advanced Spelljammer Helm||Advanced enchantment that increases speed of spelljamming vessel.||-20|
|Archaic||Vessel has a less-advanced spelljammer helm, causing the ship to move more slowly.||190|
|Ceramic Hull||Ship is made primarily from ultra-light ceramics, offering increased durability and reduced weight.||-170|
|Druidcraft||An integrated treant heals a wooden ship, at the cost of increased weight.||10|
|Gith Reinforced Hull||Giff engineering creates wood vessels with a 20 damage threshold|
|Metal Hull||Ships made from metal are lighter for the same given volume than wooden ships.||-10|
|Stone Hull||Ships made from stone are significantly heavier for the same volume than wooden ships.||80|
|Submersible||In order to be submersible, a ship requires structural reinforcement. As a result, they weigh more and are significantly slower.||190|
So, with an HP, cargo weight, a few modifiers, and a little math, you can determine the speed of a novel spelljamming vessel.
I’ll be back with more on creating your own spelljamming ships soon. Until then, take a look at these map/tokens I made for your ships on the tabletop, virtual or actual!