: Kevlar all by itself will not make a really strong layup. It will be too
: flexible. It is advisable to add some glass or other material between
: layers of Kevlar. The outermost layer as glass is also a good idea as it
: handles abrasion better than Kevlar. 4 layers of material is probably the
: minimum. Areas that see impacts may benefit from more.

I did a stich and glue with balistic kevlar on the outside. It required a lot of extra care and work to get a good finish. The boat was 4-5lb heavier than the same boat with glass! I am not convinced that the increased impact resistance was worth it! The Glass on the inside and the Plywood (3mm) gave it plenty of stiffness. If I decided to to it again I would put the kevlar on the inside and the glass on the outside.