I was told by a local police officer that if I wanted to stay legal, I could go no deeper than ankle deep. Anything more and he says you are looking for trouble. Water detecting on the east coast of Florida is problematic as the waves are a whole lot rougher on the Atlantic side. Also, sanding has been going on quite heavily lately. While I was at the Ambersands beach, a sand barge was pumping sand onto the beach and covering up the beach. Makes for a real crappy detecting experience.
Of the twelve ships that were lost in 1715, seven have been found so far. So there are 5 others that are still not known where they have sunk. All up and down the Treasure coast treasure has been found. The only problem today is the sanding of the beaches and the fact that those beaches have been pounded pretty heavily by locals and by visitors to Florida. Many of the finds have been made without a metal detector. Just people walking down the beach and looking down. The McClarty museum has a whole book about the finds made on the Treasure Coast. Worth going in and checking it out. Lots of photos and newspaper stories.
The whole Treasure coast area from just a few miles north of the Sebastian inlet, south to Fort Pierce is leased with just a very few areas not leased. Best to just stay out of the water all together with a metal detector. No detecting in the state park although detecting on the beach is allowed.
The dunes are also off limits for digging so stay inside the base of the dunes to the tide line.
There has been some finds on the beach at the McClarty treasure museum. That is the site where the survivors met and started salvaging the treasure back in 1715. That site has been the area where a lot of treasure has been found.
To get there you will have to walk from the south on one of the public access beaches. Another good place to hunt is at the former Chuck's Steak house site.
That site is now a building that has natural science stuff for sea turtles and birds. You will have to go to the public access area to get to the beach as the state now owns the area that was Chuck's steak house. There is no public beach access there.
Here is another link to information on Treasure Coast metal detecting.......
http://www.mitchking.us/water.html