The Norwegian Star is right at the limits for a Panamax vessel - those are: Length: 965 ft, and Beam of 106 ft. The Star is 965 ft long and has a 105 foot beam. So it is probably the largest cruise ship to pass through the canal, although it is not the largest ship in all aspects. That would most likely be the WW2 U.S. battleships. The locks are actually larger than the Panamax limits, and special permission can be obtained for ships larger than Panamax to lock through.