[EricH]

Depends on what "captain" you need. There are three or four that have been brought up:
--Team captain for build season. At this point, you want an organizer who is respected. His/her job is to make sure the robot gets built on time and to plan.

--Picking representative. Wait on this until much later. You want a "people person" who can take a list and narrow it quickly. Must know something of what your scouts have come up with at an event; may actually be the head scout.

--Drive coach. Required for this: Good strategy skills and a loud enough voice to be heard over the competition at close range. Wait until the end of build season to choose.

--Sub-team captains. Must be the best or close to it in that field that is available. Mentors ideal for the first year, if available; after that, students.

For the record, I don't think that there is a requirement to have a team captain. You do need a student rep to sign off on the inspection and to pick teams. (These are often a team captain, so that can be taken into consideration.)

It sounds like you are looking for a leader. My advice here is, let mentors lead for now. A student leader will eventually show up. People don't lead because they are chosen to lead; they are chosen to lead because they lead. Someone will demonstrate leadership; they should be the captain or leader.