Able crew are colonists capable of manning your * Ships ships.

The number of able crew on a colony is shown in the bottom right of the fleets tab at a colony.
It is also shown in the colony history, which you can find in the statistics tab at a colony.

Max able crew (sometimes called Crew Reserves) is defined by:
- Education
- Local Laws (Combat Readiness increases it, Legalized Narcotics decreases it)
- Military Index

Crew recruitment rate is defined by:
- Education
- Government (Autocracy increases it)
- Local Laws (Combat Readiness increases it, Legalized Narcotics decreases it)
- Military Index

While mothballed ships will be deployed to defend your colony when under attack, this is also limited by able crew available for the task.