Many of the rules from GoS will work and help in SJ, but many are just plain moot. Crews and motive forces, for instance. I'll break them into a couple posts for ease of reference.
This message was last updated by the GM at 17:10, Thu 18 Aug 2022.

Several new Background appeared in GoS:

Fisher: Fishing IS possible in the Astral Sea, but it is NOT a body of water.

Marine: replace Vehicles (Land) with Vehicles (Space) if you're a Wildspace native) Don't if you're not.

Shipwright: The abilities here are limited to a WATER vehicle. If the ship isn't capable of water landings, a Shipwright can't fix it. It also needs to be made of wood, of course.

Smuggler: If a Space native replace Vehicles (water) with Vehicles (Space)

Any of the ocean designed ships may be used, none capable of a land landing (except a rowboat).

Use the faster of the speeds (Sal or Oar) as ship's speed, with no crew, sail, or oar needed.

Crewing is based on full weapons crews plus 2 (Captain and Helmsman)

Magical equipment:
-Most are moot/useless: any oars and sails, for instance.
-a Churning Hull requires ocean gods, so, presumably, an ocean.
-There is already another sort of Living Ship in SJ, but a Living Hull could prove useful, and should keep air pure.
-Vigilant Watch Hull should give a penalty to Beholder encounters...not that you're likely to notice.

Weapon Upgrades from GoS should work as advertised, except for Concussive rounds. No crew to disrupt, although you might prefer to have the Helmsman make a Con save, instead. DC 13 or a minimally competent enchanter.

Figureheads and Misc Upgrades should work fine, with Taskmasters Drums replacing a missing weapons crewman, but not much else.

Crewing is based on full weapons crews plus 2 (Captain and Helmsman)

Still, the specialty crewmen from GoS can be used, and have tasks outside of swabbing the deck when not in combat.

With the small crewing requirements, a First Mate is needless, and a Bosun may be. Still we will include Bosun for what he can bring to ship repairs.

First off Special Actions:
Take Aim is Captain only, now. If you have a Bosun, he's probably already leading the crew of one of the weapons.

Full Speed Action is a Dash equivalent. While flying the ship is Movement, this would be a Dash Action.

Officer positions:
Required:
-Captain: Anyone other's will listen to, really. Vehicles skill is handy, of course.
-Helmsman: A spell caster that powers the Helm. Should also know Mending, if he is a professional. This is the person doing most of the ship handling, so some Vehicles would be handy here, too.

Optional: (Weapons crews when in combat, this is their other job)
-Bosun: Strength, Carpentry and Athletics. He can do repairs underway, but slowly.
-Navigator: Should know Navigator's tools. Cartrography would be handy, too, but optional.
-Surgeon: High Int, Medicine, Herbalism tools. Healing magic helps, which would make you backup Helm, too.
-Cook: Brewer's tools and Cook's tool. Think about going months at a time choking down iron rations....now hire the Cook.

Notice that actually knowing how to crew a ship isn't really required for most crewmen. It's all weapons and mops, really.

I have tried to make Saltmarsh Events work for a Space game, but... once you remove the NPC crew that sea going ships need, plus the atmosphere concerns, crew conflict, weather, even most infestations are all moot, and nothing is really left.

Oh, I could keep Infestations and make vitamin deficiencies and space barnacles an issue eery few weeks, but what's the point?

This has the side benefit of removing all the skill requirements for most Officer jobs, as there won't be any Officer rolls going on.

Apparently it takes a lot less skill to take a ship into space than it does to stay afloat.

Who knew?
This message was last edited by the GM at 18:58, Mon 17 Oct 2022.