The Great American Energy Boom is having a major ripple effect on the shipbuilding industry, which thanks to a 1920s maritime law, is busier than it has been in decades. Some ten supertankers are currently under construction at U.S. shipyards, with orders for another 15 in the pipeline. That may not seem like a huge number, but considering there are only about 75 such tankers plying American ports now, it represents a genuine boat-building boom.