Docking in a luxury marina is about the only place to catch a random glimpse of Tiger, who moves through the world in a cocoon of his own creation. When he bought his plane, he blocked the tail number from tracking websites: It ends in QS, the standard code for NetJets. Many athletes, by contrast, have some sort of vanity registration, and some even have custom paint jobs; Michael Jordan's plane is detailed in North Carolina blue, and his tail number is N236MJ -- the "6" is for his titles. Jack Nicklaus flies around in N1JN nicknamed Air Bear. Sitting on a tarmac, Tiger's plane looks like it belongs to an anonymous business traveler, nothing giving away its famous owner. He comes and goes quietly. ... He'd long struggled to sleep, and when he wasn't texting or playing video games, he'd read, often military books about lone men facing impossible odds, such as Roberts Ridge or Lone Survivor, or books about theoretical physics and cosmology. The intro to Get a Grip laid out the basic rules of early science, from Newton and Galileo, focused on the concepts of friction and gravity. These had long interested him. Five-year-old Tiger once made a drawing that showed stickmen swinging different clubs, with the clubface sketched, as well as the flight path of the ball, including distance and apex. ... He grew up without siblings or many friends. Tiger and Earl did everything together, hitting balls into a net out in the garage, or spending hours at the golf course, and when they'd finish, Earl would order a rum and Diet Coke, and Tiger would get a Coke with cherries, and they'd sit and nurse their drinks like two old men. The golf pro at the Navy course, Joe Grohman, worried that Tiger didn't have friends his own age until high school. His friends were Earl and Earl's old military buddies. ... Tiger heard the stories and saw the deep love even strangers felt for each other. His entire childhood revolved around these men and their code.

The weapon is called a railgun and requires neither gunpowder nor explosive. It is powered by electromagnetic rails that accelerate a hardened projectile to staggering velocity—a battlefield meteorite with the power to one day transform military strategy, say supporters, and keep the U.S. ahead of advancing Russian and Chinese weaponry. ... The Navy developed the railgun as a potent offensive weapon to blow holes in enemy ships, destroy tanks and level terrorist camps. The weapon system has the attention of top Pentagon officials also interested in its potential to knock enemy missiles out of the sky more inexpensively and in greater numbers than current missile-defense systems—perhaps within a decade. ... The future challenge for the U.S. military, in broad terms, is maintaining a global reach with declining numbers of Navy ships and land forces. Growing expenses and fixed budgets make it more difficult to maintain large forces in the right places to deter aggression. ... Railgun research leans heavily on commercial advances in supercomputing to aim and on smartphone technology to steer the railgun’s projectile using the Global Positioning System.

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.

Investments into a vast network of harbours across the globe have made Chinese port operators the world leaders. Its shipping companies carry more cargo than those of any other nation — five of the top 10 container ports in the world are in mainland China with another in Hong Kong. Its coastguard has the globe’s largest maritime law enforcement fleet, its navy is the world’s fastest growing among major powers and its fishing armada numbers some 200,000 seagoing vessels. ... The emergence of China as a maritime superpower is set to challenge a US command of the seas that has underwritten a crucial element of Pax Americana, the relative period of peace enjoyed in the west since the second world war. ... China understands maritime influence in the same way as Alfred Thayer Mahan, the 19th century American strategist. “Control of the sea,” Mr Mahan wrote, “by maritime commerce and naval supremacy, means predominant influence in the world; because, however great the wealth of the land, nothing facilitates the necessary exchanges as does the sea.” ... The five big Chinese carriers together controlled 18 per cent of all container shipping handled by the world’s top 20 companies in 2015 ... The total size of these investments is difficult to calculate because of sketchy disclosure. But since 2010, Chinese and Hong Kong companies have completed or announced deals involving at least 40 port projects worth a total of about $45.6bn

The ambition to create the version of the F-35 that I watched on the tarmac at Patuxent River—one that can make short takeoffs and vertical landings—was what got the fighter jet’s development under way in the 1980s. The Defense Advanced Research Projects Agency (Darpa), the Pentagon’s tech arm, began working at the Marine Corps’ behest on an improved version of the Harrier, a crash-prone vertical-landing jet of British design. According to a Pentagon history of the F-35, Darpa quietly sought assistance from a research and development arm of Lockheed Martin known as the Skunk Works. By the early 1990s, the Darpa-Skunk Works collaboration had produced preliminary concepts, and the Marine Corps began pressing Congress for funding. The Air Force and Navy insisted that they, too, needed stealthy, supersonic fighters to replace aging Cold War-era models. Out of this clamoring grew a consensus that the only way to afford thousands of cutting-edge fighters was to build a basic model that could be customized for each service. ... The degree of commonality among the three versions of the F-35—the shared features—turned out to be not the anticipated 70 percent but a mere 25 percent, meaning that hoped-for economies of scale never materialized. A pattern of continual reengineering resulted in billions of dollars in cost overruns and yearslong delays.