Just remember us guys out there fishing in our little boats do not qualify for #4. #4 is a commercial fishing boat with its movement restricted by its fishing equipment or other activities.
The dredging activities around Spring lake fall under #2. A vessel restricted in its ability to maneuver. You will notice on the dredge he is flying 2 black diamonds to let others know this.
Barges on the river I would believe fall under #3, Vessel constrained by its draft. This means its just to big and deep to go around you.
Thanks for the video Jon. Those planes seem to be doing a lot of practicing around spring lake this year to. I wonder if they pick a certain part of the river to practice on depending on the wind.