Fitting the services and technology required by a vessel of this century into the curvaceous hull of a classic from the century before is no easy task. Not least the propulsion and its ancillary equipment. There’s more to a propeller than meets the eye. The relationship between pitch and engine revs may be obvious, but then there’s the choice of types to reduce vibration – three, four, or five blades? And what about tip clearance? And when that’s all decided, check the chamfer on this blade edge.