You need to check out this site. Its the NCDOT Ferry site. It has times, fees etc on the ferries. http://www.ncdot.org/ferry/
I'm not from the area but have been there. I can tell you that the ferry from Hatteras from Ocracoke Island is very short. Its about 45 mins.
Depending on what time you want to get on the ferry will determine if you have to have a reservation or not. If you miss the ferry you'll have to wait for the next one.

The last time I was there, I took the Cedar Island Ferry to Ocracoke & we got on the first one. It was just before daylight & we had no reservation & got on. They had 2 lines. Those with reservations & those without. They loaded the people with reservations & then filled it with the non reservations. The day we were riding, everyone got one.
To be honest, I'd give the NC DOT a call & direct your questions to them.
Let us know how your vacation went. I've been through the outerbanks riding but I've never vacationed there. It doesn't look like there is a whole lot to do around there. Check out Kitty Hawk though. Its definitely worth the price of admission to the Wright Bros Memorial. Really nice place
I'm from South Carolina...You don't want me to give you directions.
