David Novo
Contributor
Around here, the dive sites for which I've seen boats require AOW are Farnsworth Bank on the backside of Catalina, and the oil rigs. Farnsworth is an underwater pinnacle; the top is only about 60 feet deep, but it drops off from there to about 200. I've dived there several times and never go below 110; most of the boats I've been on are rec-only and expect you back on board within an hour. The pilings on the oil rigs extend all the way from the surface to over 700 feet (Eureka; the twins are shallower at 260 feet.) One could certainly do a dive there with a max depth of less than 60' (I have; I've also gone to 100'). However deep you want to go, you're going to have to stop your descent before you land on the bottom. But perhaps because the consequences of not being able to do that are so dire, dive boats typically want to see an AOW card. I understand the same is true for a lot of wrecks in 80' or deeper. The 80' shark dive I did in Playa del Carmen required it too, though I was able to use that as my deep dive to get the AOW cert so it didn't delay my vacation plans.
Those are not really great examples, as the bottom is beyond OWD recommended limits...