Maybe it was a PWC!
We can only hope... I had exactly the same experience as James on my way down the
ICW. Just motoring along, when all of the sudden a GIANT Manatee surfaces right next to my 24 footer. For some primordial reason, the LAST thing that pops into your mind at that instant is Manatee. Sea monster, whale, walrus, mutant dolphin...anything but manatee. Soon you realize what is visiting you, and then you're like "Cool, I knew that..."