Posted for Walter Atkinson <walter@advancedpilot.com>:

 Well, when I used to race Maxi boats offshore, we found that a roughened hull
surface held a boundary layer of water which offered less resistance than a
very smooth, and shiny surface.  When two very close 12 meters were raced, one
with a microscopically roughened hull vs one with a polished hull, the rough
surface hull was faster.  How this would affect a laminar flow vs a
non-laminar flow wing could be another matter.  There is a boundary layer in
both.  Air being compressible as opposed to water, changes the equation, I'm
sure.  But, golf balls have dimples for the same reason, don't they?  I would
think we are wanting a smooth, non-turbulent, thin boundary layer.  There are
areas on a 747 wing where the boundary layer is almost a foot thick!
 
 ???????
 
 Walter