Until the previous Cup and 2010’s Deed of Gift match between Oracle Team USA and Alinghi, stored energy, or energy on demand, wasn’t allowed. In the IACC Class (1990 to 2007), more than half the 17-person crew were dedicated strictly to power production (grinders) to facilitate efficient tacks, jibes, sail hoisting and retrieving. In 2013, we saw the racecourses shortened and the crew reduced to 11. Once foiling was introduced, extreme fitness was required because eight of 11 sailors were grinding almost all the way around the race track to supply power demands and keep the boat operating at peak performance. In the 2017 Cup in Bermuda, the AC50 further reduced the crew to six sailors and shortened the course yet again. Accumulator tanks were allowed to buffer energy produced by the limited crew so it could be used whenever required. The AC75 Rule has an 11-crew limit, but again, a significant portion of the crew will be dedicated to energy production that three or four primary sailors will produce.