Charles and John Deane, brothers born four years apart, grew up in a foul dockyard precinct on the edge of London. A former fishing settlement on the Thames, the area had been swallowed by Europe’s largest city. By 1800, it had become a squalid reach of maritime activity and drinking establishments overlooking a fetid waterfront. ... the Deanes’ royal titles and estates had long since been squandered by the time Charles and John were born; their father toiled as a caulker, patching seams in the hulls of ships that his forebears once designed. ... many daring divers had attempted to retrieve sunken treasure in a variety of contraptions—wooden containers, copper jackets, metal canisters. Some died. Others were crippled. ... The Royal George sat in waters about 80 feet deep. At that depth, a pressure differential could create suction 10 times stronger than a modern vacuum cleaner. That might not be strong enough to rip off a face and suck it through an air hose, but it would certainly cause permanent damage or death, as was the sad fate of William Tracey and many others that came after him. ... The brothers were learning hydrodynamics by trial and error, and the crowd got a good show.