Chris:

There are a couple of Double Stack trailers in the California area that can take as many as four Formula 18s. One sits on the bottom assembled straddling the catbox. The others are taken apart and put upside down on the rack above instead of putting a single assembled boat there. they do not add much more windage than a double stacked, just a bit more weight. Add about 1000 lbs including gear to the mix, compared to the double stacker.

Later,
Dan