I dont think the hobie 16s fit under the f16 restrictions, i think the h16 is a little longer than the f16 rules allow and has a much bigger mainsail area than the f16 rules allow (mostly because of the crazy foot length of the h16 main).

Mossies+kites arent classified as f16 as we are below the minimum weight, however we can race in their open f16 division as a dispensated f16 due to our much smaller beam width, mast height and sail area. So im not sure weather the h16 is too far out of range of the restrictions to race as in the open f16 division, or weather factors like its weight is well over minimum weight or that it has a mast height under the minimum would allow it race in the open f16 div. Best go the "Formula 16 High Performance" section of the forum and ask Wouter, hes a former chairman of the f16s and one of the founding members, so he'd be able to tell you for sure.