I second that. 16 footer is much too small for 400lbs. I've sailed a 17 foot (Nacra 5.2) at 340lbs and that was it's upper limit to maintain decent performance. Had a Hobie 18 as well and it will handle the weight a little better. I now have a Nacra 6.0NA and I sail it at 375 and we're a little below middle of the the range of the class. Best bet is with a 20 footer if you are constantly going to crew with 400lbs. Nacra 6.0NA (biased)(factory spinnaker option - a lot have aftermarket chutes), Hobie20 (rare factory spinnaker option - a few have aftermarket), Inter20 (carbon stick, factory spinnaker, a lot of boats available after Worrell and Tybee races, very competative class), Supercat 20 (if you can find one and care to spend a few more minutes breaking down a 12 foot wide boat for trailering - rarely enough together to have a class at a regatta). Did I leave any major US boats out? There's talk of an F20 class that's trying to get off the ground and hopes to encompass three of these four with slight modifications (cue Carl ).

You ~might~ still want to look at F18 or F18HT. 400lbs is upper limit for their weight range but they are both classes that seem to be building. They'll sail with 400lbs - the only question is how fast (assuming you want to do some racing) and choppy conditions might begin to be a problem causing the bow to submarine. Just a few thoughts