We took the two-hour tour. The ship actually alternates between N. Harbor and S. Harbor, 45 minutes each with 15 minutes in port in between. 2-hour tickets allow you to stay for both. The S. Harbor portion was by far the most interesting, passing by a lot of Navy ships with explanations. N. Harbor was a little boring. The narration was almost impossible to hear inside, especially with many passengers trying to talk louder than the guide, but outside was better. The narration itself was not the best, being sing-song and punctuated with simplistic jokes ... but the parts about the Navy ships & some of the history were useful.
We had a big problem with misinformation from the reservation service: They told us that we would not be permitted to bring a lunch on board, and that hot food would be available to purchase. Not so... with the result that we went without any lunch except for chips. Also, they told us that we could park by the Midway next door... except that the Midway lot and the next one down were full, and I had to wait for someone to pull out of a space, and then run over a quarter mile to get to the ship as it was about to depart.