Here we go again on the wax / no wax debate.

Popcorn, anybody?

The theory behind the "slightly roughened" surface having lower skin friction is that the small imperfections allow water to attach to the surface more easily, prolonging the laminar boundary layer (lower friction) before it becomes a turbulent boundary layer (more friction).

This is a real problem in model tank testing to the point that "turbulators" (small wires) are installed on the bow of the model to induce a turbulent boundary layer. Otherwise, the model is "slipperier" than it should be, throwing off the test results.

In reality, the frictional difference bewteen the two surface conditions is negligible on small catamarans. There are too many other factors affecting your boatspeed (sailtrim, boat handling) to worry about the skin friction of your boat. One slow tack will more than compensate for the difference in skin friction.

Additionally, the benefits of waxing the boat include UV protection, sealing the pores in the gelcoat (so the boat doesn't soak up tannins - brown stains - from the water) and it looks a lot better.