It has the spring of a racehorse and the agility of a barrel turner. If you’ve ever ridden a well-behaved thoroughbred, it knows what to do — all it needs from you is to understand your intent. The R5 is like that, offering a oneness with the ride that seldom comes along in boats. Nudge the wheel to port and feed in throttle, and it carves a rodeo turn so tightly and so smoothly that it’s infectious. The starboard curve is equally graceful; not many boats are so ambidextrous.