18 foot with 150 kg crew and 180 kg boat = F18 = overall weight 330 kg

Using your rule :

F14 weight = 0.47 * 330 kg = 155 kg = 80 kg crew (singlehander) + 75 kg boat

Or 70 kg crew + 85 kg boat

Works out quite nicely

Wouter


Wouter Hijink
Formula 16 NED 243 (one-off; homebuild)
The Netherlands