Dropped my Olympus TG 4 last time at Willy T while getting out of dingy. a few people tried diving for it at night, talk about crazy. One of the guys who works on the Willy T said he free dives the area every morning and would see if he could find it. I came back the next morning and he had it!. Camera spend the night at 40 feet and works perfectly. Not a drop of water entered the case. Tipped the diver $20 . He said he finds all kinds of things below so hopefully your GoPro will be found.