I would do one one of two things:
1) if this were for a single adventure or small set of adventures, I would detail a couple of specific personalities and then have some random traits handy for handling random interactions (both personality traits like "hostile to strangers" and physical ones like "has an odd crescent scar on one cheek"). I would also invent details on the spot for specific characters, and record those inventions so that the party can go back to "the guy who really wanted an orange" or whatever.
2) Alternatively, you could consider running an entire campaign around this cast. 190 people is certainly a large enough group to keep things interesting for a long time. In this model, the things that would normally be the "adventure" (like travelling to new places, getting attacked by pirates, etc.) become almost the background for a very role-playing centric model. I would come up with a reason why this particular ship was important (possibly because of the PCs, possibly because of something about the ship itself) and then build motivations for the NPCs that justify their presence. There would be cliques and rivalries, possibly secret societies and scheming (and probably at least one NPC who is some sort of other creature in disguise). The general arc would be that things would stay subtle for the first little while, then the PCs would start to uncover some of the funny stuff going on, at which point I'd have a "big event"...probably stranding them aboard the ship unable to do anything but drift, and then put the screws on.
