>>2422543This. Get certified if you want to dive, Anon. Don't do it hoping to collect stuff. Even if you found something neat, laws about wreck ownership are much stricter than in Mel Fisher's day. If you're in the US, they passed the American Shipwreck Act after he found the Atocha, which greatly limits wreck treasure hunting.
Furthermore, massive amounts of historical and archaeological research go into finding new wrecks. As an amateur, you likely won't find anything like that, and if you do, you'll probably destroy whatever historical/archaeological value it has. Buy a boat to have normal diving fun, not treasure hunting.