ORIGINAL: rhall999
Well fellas I'm no expert, I will admit that. But if you can not see the bubbles swirl right aft of that boat prop, maybe you need your eyes checked. Granted, the prop rpm is pretty quick, and the bubbles swirl pretty quick, but the presence of the swirl is obvious.
There are also plenty of photographs of props creating vapor trails as they taxi.
Same phenomenon. The vapor trail and the bubbles are right where the prop tip created them. They are particles/objects left behind, right where they were created. They show you where the prop tip was as it passed through.
The swirl and the vapor trails are obvious. But really don't prove anything more than the tip was there.