BRINDABELLA, 64ft IOR Racing Yacht

Designer’s Notes

The brief was to design a boat with good sailing performance and fun for the price, approximately 65 feet length over all, not too distorted by the IOR, and capable of racing successfully under the IMS rule. Developing the ULDB concept to feature better all round performance characteristics, Farr Yacht Design designed a fractionally rigged 64' yacht, strong and well balanced, with a deep bulb keel for high stability, and a deck arrangement to suit a crew of 14 or more. With more beam and displacement for her size than the typical California ULDB "sleds", Design 220 offers sufficient ballast and form stability to be a significantly better boat beating and power reaching relative to her IOR rating of 62.3'. BRINDABELLA should be very competitive with the "sleds" downwind due to IOR penalties for very light displacement which rob them of sail area. The increase in displacement of this design allows a significant increase in sail area resulting in a comparatively higher sail area to wetted surface area ratio. This counteracts the higher wave drag caused by the greater displacement at high speeds. The project budget excluded flippant use of exotic materials in the construction. The brief demanded a reliable, robust structure suitable for ocean racing and cruising work off the Australian coast with a sensible compromise between cost and weight saving measures. The structures developed utilize unidirectional S-glass laminates over PVC foam cores. Internal structures are a mix of foam and timber bulkheads reinforced with S-glass laminates. An aluminum subframe supports the keel to provide reliable resistance to grounding and broaching events. The mast is fractionally rigged with the capability of using a masthead spinnaker or genoa under separate IOR certificate for long distance downwind races and still rate within the IOR maximum of 70 feet. It has long been the contention of Farr Yacht Design that the typical California ULDB "sleds" are too light to be optimum under the IOR for the predominately downwind conditions off the United State's west coast. The current Whitbread Round the World Race bears this out as the ultralights have been very lackluster against the more moderate boats except in strong running conditions. We expect Design 220 to fit nicely between these two types to give sparkling downwind and reaching performance combined with healthy characteristics in other conditions at an attractive cost.