Gerr Elements FRP Ambiguities?

6.6m LOA, 6.2m LWL, 1.8m beam, 0.15m draft, 660 Kg disp, 18 knots max speed.

ISO sheet in VectorLam is indicating < 18oz fiber weight required for outside hull skin. Even less for the inside skin. 18 oz E-glass woven roving on either side of 6mm of CoreCell M80 results in stiffness and section moduli all in excess of that required. "Skin Wrinkling Critical" is "YES", no matter what I do. I double checked my Gerr spreadsheet and it produces glass weights in the same ballpark, using the most aggressive (least conservative) interpretation, but significantly larger minimum core thickness.

I guess my big hang up is that I've been elsewhere advised to use much more glass than this to provide the necessary puncture resistance. I haven't acquired a tool or technique to estimate this, so I'm struggling to get a grip on it. Perhaps this is what the minimum fiber weight requirement is all about?

 

Minimum means just that !! dont use anything less !! very simple !! Its the bottom line !! dont go below !! on the other side of the coin dont get all carried away and double weights either think about what Glasses they recommend and why they recommend .Woven uses more resin than stitched but a woven is ok for a work boat situation as its a little more robust than stitched plus with stitched you should up the resin quality to a good Vinylestster specially if there is any impacting involved . Stitched fabrics will give a stiffer panel than woven!!