Hidden Treasure!
It was the gold! Carefully hidden in the canons, the sailors put the gold there to keep it safe from anyone that would come across the shipwreck. All of the coins, hundreds of them, were all solid gold. Then, it was like a faucet they couldn’t turn off. Gold coins were being found everywhere in the thick mud. 45 minutes after finding the gold and searching for more, they found the actual treasure chest.