This is an idea that I've been considering for some time, mainly as an alternative way to managing NPC crewmen in the Frozen Skies campaign that I ran but struggle to come up with something at the time. Currently preparing to run a game in a different setting and system, one that involves spaceships and a degree of crew management. This other game prompted a train of thought and I've think I've come up with something that'll work for Frozen Skies.
Mariners of the Air
This is intended to be an optional set of rules that builds upon the Wealth Rules in SWADE, targetted at hose who like a little bit of bookkeeping and wish to have airships with sizeable crews. These rules come in two parts; Wealth Pool and Crew.
The Wealth Pool is a Wealth roll for the character's airship and works in a similar fashion. It starts at d4 but the characters can increase it by 'investing' in the collective wealth pool by transferring a die of their own Wealth to the Wealth Pool. In gameplay the characters can use the Wealth Pool instead of their own Wealth for trying to buy items, though the Wealth Pool is also used to make a once a month Upkeep roll for the airship. This roll represents the general upkeep of the airship, buying spare parts, fuel and supplies for the crew and works the same way when buying things. Though if the Wealth Pool goes 'broke', then the characters must transfer a die each of their own Wealth to avoid a mutiny by the crew.
Crew is, unsurprisingly, the crew of the airship. They start with a collective trait die of d6 for the relevant trait rolls they may be required to make (Shooting, Piloting, Repair, etc). This trait die (or Crew Rating) can be increased one step by reducing the die of the Wealth Pool by one, like downgrading the Crew Rating can increase the Wealth Pool as a lesser crew cost less in wages. The lowest Crew Rating will impose a -1 penalty on the Upkeep roll that will build up over successive months to a maximum of -4 if the Crew Rating stays at this level, representing the increased upkeep costs with a poorly trained crew.
Incompetent - d4 - Upkeep rolls incur a -1 penalty that increased by -1 per month (to a max of -4) that the crew remains at this rating.
Competent - d6
Crack - d8
Veteran - d10
Elite - d12