PROBLEM SOLVED!! Look on the sides of the pods, you'll see a "pod plug" (that's what it's called in the Navigator manual)...pop this off with a flat screwdriver and see if the "nut"(for lack of a better word) is loose. One of ours was, and luckily we found a tool to tighten it back down. Sorry I don't know what you'd call this tool but ours fit exactly over this nut and we could turn it to tighten.
Only one side was loose, which would explain why it kept going in one direction making circles until the hose was completely tangled in a knot.
This is a brand new Navigator, and I'll assume it came from the factory this way since it was doing this from day one.

Hope this will help others out there who are having a similar problem....it's just one more thing to rule out. Apparently if those 2 pods are not moving equally, it will cause your vac to go in one direction resulting in circles.

Here's the killer....we had some pool guy check it out (before we figured out what the problem really was) and he said we had scale on our diamond brite finish and needed to have it redone. Suckers that we are, we spent over 3 grand to do it and still had the same vacuum problem after all that....and the guy who came to do the diamond brite job said "You don't have any scale in this pool!" So obviously that wasn't the problem with the vacuum!

Nancy