That coordinate marks the inner edge of the outer "third" reef line. The depths vary to 60 or more feet. This line is much more prolific with marine life, turtles, fish, sharks and generally densely alive. This is also the same line of reef charter boats regularly dive. Much more accessible via kayak obviously and more practical.
I believe this photo is from that general area:
This is the inner reef line near the three balls southeast of the pier at about 15 feet, not the same day or same camera:
I usually use steel 72cf tanks, aluminum 64cf tanks or rarely an 80cf for beach dives. My SAC rate is very low and any of those tanks are more than enough air. And, importantly, if I need to walk a mile or so back to my car (or where ever my wife can find me) I am not weighted down with unnecessarily heavy gear. I generally use very simple gear, usually no BC(D) and as little neoprene as I can do with.
To be clear, once again, I am not recommending anyone swim 1.5 miles or more offshore solo and with no surface support. I am simply saying, that I can and I have and will again. My methods suit my experience and capabilities and I value simplicity and speed. My swim out and back are done on the surface and I basically haul aXX and even at that a dive of this nature can have me in the water for three or even four hours. While I have never really had an issue with boat traffic here, it is a concern and as others have advised, better keep a look out.
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