The iconic Shelter Island 38 Runabout, which got a lot of attention when Billy Joel launched hull number one in 1996, is now being built with outboards. The original boat had twin 415-hp MerCruisers with Bravo 3 drives and counter-rotating  props, delivering the “Newport by lunch” speed that Joel wanted. More recent versions have been powered by 370-hp Yanmar diesel sterndrives, topping out at 45 knots. Now, with twin 300-hp Mercury Verados, the top speed is about the same, but the outboards are quiet, and they can be lifted up for running in shallow water. Almost 30 years ago, the…