Stimson Yacht Design

Performance cruiser

The Design Problem: To design a 60ft fast passage-making cruiser that is genuinely fast and still competitive under IRC in race-mode.

Solution: The starting point for this design is the stated requirement for a light, fast cruiser that is easily sailed short-handed trans-ocean. An optimum must be found between the speed-producing drive for increased length – and its attendant seaworthiness - and the requirement for smaller and more easily managed sails and sheet loads, which would leave a larger yacht under-canvassed.
The approach taken has been to regard 60 feet LOA as the minimum length capable of meeting the offshore capabilities, accommodation volume, and speed to generate the high daily averages. However, whilst a 60 footer’s sail plan may be manageable by the Open 60 racing fraternity, the conclusion is that such a rig would be excessive for the cruising requirements of this project.

One benefit of a canting keel configuration is the high righting moment available, which enables the yacht to sail at low heel angles without the need for crew weight on the rail,

and the yacht’s waterline beam can be reduced, due to the high contribution of the

canted keel to stability. This makes the yacht more easily driven, which in turn implies less sail area is required to attain adequate performance.

The options regarding the arrangement of keel and lifting surfaces were considered in light of our involvement with the Jo Richard`s-designed Full Pelt X and the keel placed forward of the centreboard. To better understand the drag profile of the hull through the speed and heel range a CFD investigation was undertaken, and the results of this fed into the VPP and used to determine the balance of race and cruise sail plans and sail-crossovers.

The negative side effect of the narrow waterline beam, in combination with a light displacement, is that there is a smaller accommodation space compared to other 60 foot cruisers in the market. In fact, the proportionally narrow waterline, and fine forward sections leave a useful volume more commonly found in a 50 footer. However, the low drag aspects of the hull also point to a sail plan more in keeping with a conventionally ballasted 50 footer in cruise mode, and a full-blown sail plan in race mode.

The exterior styling and interior layout has been designed in conjunction with Roel de Groot. The interior partitions are lightweight foam or honeycomb-cored panels, and aircraft

grade catches and latches are used to save

weight further. The yacht has been divided into four watertight compartments, with a crash bulkhead just aft of the forestay, a watertight bulkhead at mid bow with an access panel, the mast bulkhead has a passage-making watertight door and the rudder and steering gear are contained in a watertight compartment.

A two-spreader carbon rig, with additional topmast jumpers, has been adopted. Sweepback of 20 degrees and no runners makes for a simple, easy to handle set-up. The non-overlap Genoa is also a user-friendly configuration. In cruising mode this is set on a roller-furler; when racing a twin-groove headfoil allows conventional racing sail changes to be made. Offwind, masthead and fractional asymmetrical spinnakers cover the spectrum. It should be noted that the Code Zero & A-Sail are tacked on the bow rather than on a sprit or prodder.

One could regard this yacht from a sailing platform point of view as a ‘long’ 50 footer - it has the beam, displacement and sailplan of a conventional performance 50`, the length, security and easily driven hull of a 60`, and the stability of a medium displacement 70’. This is a recipe for speed. < back