It would be very difficult to fail the AOW dives. If you do the dives, you will likely pass regardless of how bad you screw them up. If you can not complete a dive, you will have to retake that portion of the class (well I would HOPE your LDS follows that minimum rule), but failure is not generally an option, and IMO it should be! :blinking:
If your Nav skills are poor, practice. Go outside, and attempt to navigate to a destination until you can do so without visual references. If you can not do it topside, you have no chance of success UW. If you don't own a compass, buy one. My favorite is the Suunto SK7. I use a DSS wrist mount vs. the wrist boot that comes with that compass. They are on the high end price wise, but we are talking $65 or so, IMO not much. Unless you loose it, or run over it with a truck, it is a once in a lifetime purchase.