Fun fact, I actually have treasure hunted. I worked on a treasure hunters boat in the Bahamas for a short time after I graduated high school. Some of the stuff we brought up is in one of the late Mel Fisher's museums.
Granted we didn't find actual treasure at that time, well at least not what is considered treasure.. We did find several copper ingots that back in those times was considered treasure but in today's times it was just giant pennies with historical value.
We did bring up several cannons and various, swords even crossbows and other general items which isn't all that rare but we did find the most complete intact Spanish helmet that had ever been found in the "New World'..
Anyway this was the page on Mel Fisher's site but seems the link is now dead and all that's left is the cached link it seems..
Mel Fisher Maritime Heritage Society and Museum in Key West, Florida