Design № 137
< Back to all designs
This design commission came to us from noted yachtsman and author, Newbold Smith. With extensive offshore cruising and racing experience, Smith wanted a yacht to replace an existing one of similar length. The new boat was to be very comfortable and well appointed cruising yacht fulfilling Smith's own interior requirements and, at the same time, be a high performance yacht with exceptional handling characteristics able to race very competitively under fair minded rating rules and handicapping systems, (MHS, PHRF) without being unduly penalized by the IOR Rule.
The key to handling and performance is a hull form of light to moderate displacement, (displacement length ration = 159); very moderate beam to length ratio and easy undistorted lines, coupled with a high aspect ratio optimum area keel; good stability from a high ballast ration and low center of gravity; and, a good sized sailplan. To obtain the necessary ballast ratio, at the same time as including a full interior in a lightish displacement boat, exotic materials were used throughout the hull construction and interior joinery with particular attention being paid to weight reduction in the ends of the yacht.
Our experience in design and construction with high quality, hi-tech Kevlar laminates and the resultant reduction in the premium paid for use of this race boat technology, now makes it extremely viable and desirable for construction of high quality cruising yachts. This design calls for a predominantly Kevlar laminate throughout and utilizing a thick high density Divinycel core which gives both high strength and stiffness, as well as, good thermal insulation and exceptional impact strength.
Interior joinery is honeycomb cored wherever possible and the resulting weight savings in the interior and the total structure have enabled a 45% ballast ratio in a relatively light displacement boat carrying a fully fitted luxury interior. The rig chosen is interesting in itself, in that it features a masthead rig with short J and long E. This reduces the size of the head sails assuring of handling the rig and provides a mainsail large enough to realistically handle the boat under mainsail only. The rig size is actually quite large, giving a sail area displacement ratio of 21.3 which strikes a compromise between the yachts racing and cruising demands.
While racing the boat she will have ample sail area for exceptional light weather and moderate down wind performance. For cruising, the #1 genoa can be left in the bag as the #3 jib will give all the necessary cruising performance with the advantage of easy tacking and the versatility of covering a very wide range (5-25 knots of true wind) without a headsail change.
Perhaps the most interesting aspect of this design is the keel configuration. Mr. Smith wanted to have quite moderate draft for all the good cruising reasons but also wanted a keel with a very high efficiency to windward. He did not, however, require extreme shoal draft that is normally associated with keel centerboard arrangements. Therefore, for this particular boat we were able to use a keel centerboard arrangement which consisted of a relatively narrow fixed section which when lowered formed a continuation of the basic keel section rather than an additional appendage. This allows for great efficiency in both the extended and retracted positions and our computer performance predictions indicate this arrangement will be more efficient both to windward and downwind than a conventional keel of "normal" deep draft. Keel lift is by hydraulic ram above water level with a cable linkage that can be accessed at the lower end for service with the boat sitting on the bottom with a 2-foot drop in water level.
The boat has been built by Concordia in South Dartmouth, Mass., and the interest shown during construction has already sparked commissions by yachtsmen for several similar designs.