...but when I learned to dive, 25 years ago, we did ALL our work in the ocean. There wasn't any pool work.
We met at the park near the zoo in Honolulu, and did our "book" work sitting on the grass. Then got geared up and for the second part of each class, waded into the ocean and did skills training in 4-6' of water off Waikiki Beach.
We did our checkout dives, in Haunama Bay marine park, out the other side of the Diamond Head, and it was there, that we each completed a 30' free ascent to the surface.
For the final dive, I was buddied up with one of the girls in the class, and as we went into the water, she grabbed my hand. The farther from the beach we went, and the deeper we got, the tighter her grip got! I finally moved her hand up to my wrist, and soon her grip was so tight that my hand was turning blue from lack of blood. When we got out past the reef, and the instuctor turned to us, to do the ascent, I quickly peeled her hand off my arm and slapped it in his hand, and they went to the surface. I hung there on the bottom and rubbed my hand to get the circulation going again, and waited my turn to surface. Took my regulator second stage out at his motion, looked up and swam slowly to the surface. It was the longest 45 second of my life!
So I guess my first OW experience was the first day of class, and they were all OW after that....