I would advise against the Whiskey Wreck. There is very little left to see of it. It was a wooden boat so the surge and waves and hurricanes have reduced it to pretty much just a 2 or 3 foot tall section of hull. It's been beat to hell over the years and probably won't still be there in another 10 years. I say no go.
The Perdido Pass Jetties are some great diving and snorkeling, assuming you get there at the start of high tide (10-11AM most of the time). I've seen the jetties in 50ft vis and I've seen them in 6 inch vis. If it looks bad from the top of the sea wall, DO NOT DIVE IT! Every time it's ever looked bad from the sea wall I've been stung by a jellyfish. Any time it's good I never get stung. I think it has to do with low tide pulling all the jellys that got washed into the bay at high tide out. Deepest I've been at that sight is 60ft, and I think I was in the middle of the bay!
You can see plenty of Sheepshead, flounder(spearfishers frequent the spot, so watch out), redfish, and I've even seen octopi and lionfish!
The Perdido Bay Bridge is another good shallow dive, about 20-something feet max. Good dive where you can see small shark, redfish, sheepshead, jellies, and small children jumping from the pylons (watch out for the little ****ers, I knew someone who had one kid jump right on his head). The current can get BAD at low tide so plan accordingly, also the vis gets bad at low tide. The pylons are really cool to see underwater!
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Also, the sea wall perpindicular to the jetties is a great snorkel. Someone told me that there is a dresser someone threw over the sea wall, and others tell me it's a piece of an old bridge, I've never seen it firsthand, just from the sea wall. Plenty of small fish (watch out for nets from the fishers above! They try to catch the small fish in nets!) and lots of stingrays. Also, I see some massive stingrays and some bigass flounder every time I hit the jetties. Overall it's my favorite dive of all, aside from the USS Oriskany, of course. I'm a wreck freak!