Huge oversight with Spelljamming Ships

Unlike other vehicles presented by Wizards, Spelljammers are not immune to poison or psychic damage. The wood, ceramic or metal of your ship can suffer from both an upset stomach and a crippling headache. Just... ugh.

In the book, they aren't presented as NPC/Monster stat blocks like in Ghost of Saltmarsh and Descent into Avernus. Heck, even doing that was introduced later. None of the PHB vehicles have monster stat blocks that list damage & condition immunities, and ability scores. Personally, that seemed like a really weird choice where they felt the need to waste space on stating the obvious (like galleons have no intelligence or cannot be blinded, charmed, frightened, etc.). Would have been nice to have had that space used for something actually useful rather than utterly pointless. I'm glad they avoided that with Spelljammer.

So you can no more use poison or psychic damage on a Spelljammer ship than you can on a door or chair.

I think the books should specify they are immune to poison, and psychic. Maybe should be immune to fire for the metal and stone ships.

Although spells like Mind Sliver targets a creature. And a ship isn't a creature. Fire bolt can target an object. Poison Spray only effects creatures.

So the ships would have really weird stats. Look at the rules for strength. Your carrying capacity is your Strength score multiplied by 15. Multiply this by 8 for Gargantuan creatures. This is the weight (in pounds) that you can carry. These ships can carry at minimum 10 tons(20000 pounds). So their Str would be 20000 / 15 / 8 = 166 Str. An Ancient Red Dragon has a strength of 30. They can carry 30 * 15 * 8 = 3600. Or about 1.5 tons.

Their speed is about the same as player character so maybe there dex would be similar. There HP is about the same as Adult Red Dragon. So you could give them a Con score of around 25. Mental stats don't make sense at all. Spells targeting the mind should target the driver.