I didn't realize that. So you are saying if we do the AOW version of navigation and then want to take the entire class it counts for the first dive of the 3 required?
That depends on the instructor. Most will allow that BUT it won't generally reduce the cost of the class. So even if you do UW Nav as one of the AOW dives, insist on all the UW Nav dives for the course. That extra dive may give you a skill you didn't have or even realize you needed if the instructor is really good.
I have seen shops that use the AOW to get out of giving a diver they dives they paid for when they then decided to take the full class.
An extra day or extra dive is never a bad thing.
Personally I always recommended Rescue or a rescue skills workshop as the first class after OW. Some agencies don't require AOW for rescue. And no reason why they should.
A good Rescue class is as much if not more about preventing accidents and most of that occurs on land. Not in the water. There are those who say you need the UW Nav dive to do an effective Rescue. Totally false.
And you sure as hell don't need 40 dives or perfect buoyancy to tow a diver in, bring one up from depth, or save a panicked diver.
In my second book,
SCUBA: A Practical Guide to Advanced Level Training, I go into much more detail about choosing AOW training and getting ready for it. As well as what to look for in an AOW class.
For SEI, NAUI, PDIC, and BSAC and CMAS courses those are taught as part of the basic Open Water class. So making people do AOW or get 40 dives in is a money maker more than anything.
I always offered the Rescue Class and a one pool session one day open water rescue workshop for those who felt they were not ready or did not have the time for the two pool session, two day open water rescue class.
Usually they soon discovered the rescue class was not beyond their ability as a new open water diver.
If you think about it, why would you wait to take a class that gives you a new level of risk awareness and how to respond to problems or prevent them before you take classes that give you access to dives with a higher level of risk?
And you can always take a rescue refresher down the road if you feel you need it.
That said, UW Nav, if taught properly, can go a long way towards improving you and your wife's buddy skills, communication, cooperation, and help integrating each others strengths and weaknesses. I had a couple tell me that my UW Nav class helped in their overall communication as a couple. BUT, the class needs to be a good one. Emphasizing buddy skills, working as a team on UW Nav skills, sharing the task loading, and trading skills. If you are good with a compass, she should use it on several dives while you take note of features, monitor depth, etc.
It really is on the instructor to make the class a good one that actually gives you skills. They need to go above and beyond the book/standards. I looked at 8 or 9 UW Nav standards and if taught by the book alone, they all pretty much sucked. So I wrote my own that met the standards and far exceeded them.
I made it so there were 6 dives instead of the usual 3 or 4, included the use of lines and reels, and emphasized small steps that enabled people to be more successful and build on those successes. Thus getting more confident rather than frustrated and getting more accurate over "close enough" and it worked.
