Un
Floating
Object?
Well, USOs are Unidentified Submersible Objects reported thousands of times by observers all over the world. A logical thing as airtight spece vehicles can be watertight vehicles.
Whatever that library student assistant and her friend saw was able to go underwater and above it to fly. She had no advantage to be gained by telling about it, and people get ridiculed and lose credibility if they do tell about it. She was a highly intelligent and level headed young woman and a non druggie and non-drinker.