This year new modification was made as resumption from 2015 and earlier years theme " negative rocker is not bad if applied with step and not too far from forward foot strap".
At first stage as in previous years linearised 2D theory of planing thin profile and 2D VLM method were used to choose the parameters of camber and appropriate values of lift coefficient CL
Than estimations of the same profile applied to 3D rectangular wetted surface with Aspect ratio = 2 were made by
3D linearised VLM methods and predicted rather high Lift/Drag K ratio = 13.5 with values CL =0.086 ( Cb= 0.043) at 1.5 degree trim angle.( Cfriction taken 0.003) 
It is known that boards with tail negative rocker have tendency to stick the nose to the water with speed increase. It can be somehow explained by almost quadratic dependence of Lift produced by concave area in the back on velocity . So the section of cambered profile is placed for modification almost between forward and back foot straps .To avoid much ventilation of the fin decreasing height of step is used towards the center line of the board. The experimantal data presented in E.Clement Dynaplane project and Epstein L.A works were considered as a base of good air ventilation of main area of after body even with not high % height of step to bottom width .
As if keeping the same wetted spot and trim the lift rises quickly almost like squared Velocity , the desired range of V for optimization was selected only 40-55 kmh for 77-80 kg amateur windsurfer in medium wind conditions with 35-37 cm fins and with 7- 7.8 m2 cambered sails.
to be continued .....Aleon 2019