I'm not sure if anyone found this out before or not but it's something I've been wondering for a long time and just found out by accident.
I had a captain held prisoner in my cargo hold which I let free. In my rush to exit the screen I clicked on the talk aloud button by accident, and there was an option that said some slaves wanted to join the crew.
You don't have to be in the cargo hold for it either. I still had some slaves left over and I was in town and I just clicked speak aloud again and I got the option again to recruit some slaves.
I had a captain held prisoner in my cargo hold which I let free. In my rush to exit the screen I clicked on the talk aloud button by accident, and there was an option that said some slaves wanted to join the crew.
You don't have to be in the cargo hold for it either. I still had some slaves left over and I was in town and I just clicked speak aloud again and I got the option again to recruit some slaves.