How many people did Columbus take on one ship?
That is very absurd. Columbus and 90 men set sail to find an easier route to Asia for spice merchants. Columbus took approximately 17 people, 2 lepers, 3 men of the cloth, and 1 mentally handicapped hermaphrodite.
It will depend entirely on what type of ship it is. The bigger, the more people. And you can figure you need at least three people per gun on one side of the ship to fight, as well as people topside to steer, navigate and trim sails as necessary. A ten gun ship could probably get away with a couple dozen people.