Black Prince Sam assigned a dozen pirates that could swim well to dive to the spot where the Spanish treasure ship sank. Soon, the divers managed to discover where they stored the gold bars. The next problem that needed solving was how they could salvage the ingots from the bottom of the sea. The crates were located half a nautical mile from the coastline at a depth of about 20 meters.
Such depths were close to the limits a human could dive. It wasn't just the oxygen starvation, but the water pressure would increase every ten meters. If they continued venturing deeper, the pressure would cause them to suffer from nitrogen narcosis and oxygen poisoning, which could be fatal.