Owen Clarke Design have been steadily building a portfolio of design consultancy work in the field of classic yacht refit and restoration especially on traditional, classic racing and cruising yachts for IRC, JCH, CMI and Meter class racing rules. Optimisation work has been undertaken on older racing and cruising yacht designs from the boards of S&S, David Cheverton, Harrison Butler, Gary Mull and T Jackett. OC recently completed appendage re-design for one of the modern classic Spirit Yachts, extensive IRC rig and deck optimisation work on the classic yacht ‘Misty’ and previously appendage optimisation on the 12 Meter USA 61.
Working from the most basic supplied information of old printed paper drawings or having a vessels true shape digitally scanned to generate a 3-dimensional virtual model to manipulate on the computer screen. Simple sail plan optimisation including balance calculations can be carried out using traditional methods or working from first principles and utilising the most modern software applications available. Whether it be Gaff, lug or more modern Bermudan rigged vessels Owen Clarke can fully adapt the modern yacht design tools to improve performance, balance and handling of old classic sailing yachts.
With ‘Misty’ the structural implications turned out to be the limiting factor in being able to increase the size of the rig as the owner wished to limit any potential pitfalls of the extra stress on the existing structure by maximising sail area and power. Having reviewed masthead and fractional rig options on the VPP (performance prediction software) Vs the data from the max number of IRC trial rating certificates, the final, fractional rig chosen, has a mast height developed for the boat of 50ft 6in (15.4m) above the designed waterline. The equivalent dimension for the original rig was 42ft 7in (13m), and for the 1964 redrawn (but never fitted) rig was 46ft 3in (14.1m).
Another typical short-term consultancy for the Dartmouth office followed a request by the experienced owner of the 42’ on deck 1910 Westcountry based Gaff cutter ‘Cynthia’. The client required a design review for a new rig and sail plan geometry before commencing the build of the spars and commissioning the sails. This work was carried out by Allen Clarke, one of our designers, himself a classic wooden boat owner, using only the most basic historic small-scale paper drawings provided by the client as a starting point. ‘Cynthia’ has proved to be successful on the classic yacht racing circuit winning at her very first outing and with only a 150mile delivery trip to smooth out some of the wrinkles of a painstaking restoration.
For an explanation of the technology behind the design process go to:
NAVAL ARCHITECTURE
For an insight into our engineering and detailed design work go to:
ENGINEERING
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