Credited with a combination of technical brilliance and first class design, Perini Navi has always been in a class of its own. The E-volution concept offers contemporary design combined with the best in comfort and performance under sail. The Classic takes Perini Navi’s evergreen design DNA and adds a contemporary twist by offering thoroughly modern performance combined with sleekly traditional lines.
CFD Analysis and Investigations
Cape Horn Engineering were proudly commissioned for their technical expertise to evaluate the sailing performance for 3 candidate keel conﬁgurations on the E-volution and Classic 47 metre cruising sloop.
After reviewing the results of the initial 3 candidates, a dagger board, centreboard and lifting keel, a 4th variation as an improvement of one of the conﬁgurations was investigated as well and compared with the previous options.
Lifting keel option
The simulations were carried out following Cape Horn Engineering’s best practices at full scale with 2 Degrees-Of-Freedom (sinkage and trim), free surface deformation, viscous and turbulent ﬂow using the state-of-the-art software package STAR-CCM+.
In the simulations the yacht model was free to heave and pitch, similar to a run in a towing tank test. Important inputs of the simulations such as centre of gravity, the centre of eﬀort of the sail plan and the rudder stock positions were considered.
The resulting forces and moments were given for the whole yacht, as well as for its components; the hull, ﬁn keel, bulb and twin rudders. The forces and moments at the centre of mass and axes aligned with the yacht were also given, useful for comparing the dynamic righting moment of the diﬀerent yacht models and sailing conditions. Forces and moments for the torques and the bending moments in the rudder stocks were also given. Sinkage and trim were also tabulated.
Forces and moments for each conﬁguration on the hull and the appendages were delivered to Clay Oliver for further analyses with the VPP.
Video shows CFD analysis, 47m Peri Navi E-volution / Classic with 3 candidate keel conﬁgurations showing the wave patterns and streamlines.