This is also somewhat related.  The bumps on the leading edge of foils cause vortices to form.  Just like with the golf ball, the overall flow stays attached longer even with increased turbulence.  For a foil that means a greater angle of attack before stall.  That gives high aspect/smaller area rudders more bite at high angles or low speeds.  The rudder can be smaller and therefore less drag. I expect at low angles of attack the flow is still laminar.  

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