Design Evaluation and Alteration of The Dark Harbor 17.5

by Luis G. ALESSIO
Posted on November 14, 2016

While there is still a strong passion and interest for traditional crafts, many of the designs now need to be adapted to comply with the contemporary rules and regulations, and additional modifications are required to meet modern expectations, in areas ranging from comfort to safety; hence the need for modern replicas. In order to ascertain the constraints on modern replicas, a redesign of a Dark Harbor 17.5 will be proposed. First, an initial design evaluation will
be performed to assess the characteristic of the original yacht, regarding hydrostatics, hydrodynamics, structural arrangement and stability. Modifications in accordance with regulations and owner’s requirements will then be implemented to create a modern replica suited to today’s market. Finally, the new design will be compared to the original one, allowing to evaluate the challenges of design modernization and the impact of contemporary requirements on a traditional design.

Designed in 1908 by B. B. Crowninshield, the Dark Harbor 17.5 is a classic example of a traditional day sailor. It is the particular lines of historic vessels that make them attractive and elegant and still lead a number of sailors to choose traditional boats. However, true replicas can prove to be unsuitable from a commercial point of view. Indeed, traditional designs were not conceived for contemporary rules and regulations. Plus, what used to be inexistent or a luxury feature, such as an engine on a small sailing vessel, has now become norm. There is, therefore, a call for modern replicas, complying with the relevant regulations and offering a similar standard of comfort as modern boats.

To investigate the challenges resulting from thosemodern replicas, the redesign of a contemporary Dark Harbor 17.5, currently being built at the IBTC
Portsmouth, has been undertaken. The initial design has been assessed, to later allow a comparison with the modern version, with particular emphasis on the issues raised by regulatory compliance and the incorporation of modern comfort elements.

Sail plan of the Dark Harbor 17.5


Structures of the Dark Harbor 17.5


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