I have a Nov 2013 lift
when riding through Swells it has a tendency to track sideways , this I believe is caused by the pressure wave under the surface .
I have heard this from others as well.
To over come this added a small win tip Fin to work as a vertical stabilizer .& it works great .
Also to improve performance used glass putty to file in he hole on the fuselage where the retaining Nuts are .& also in the gapes between the foil & the fuselage .
the workmanship is not real good , but it works well .
Happy foiling . .