Raffia grass works quite a bit better on small layout style boats like a pintail. The grass will almost certainly get fully wet and Raffia grass will outlast grass mats by a couple years at a minimum in those conditions. Buy it in bulk from J Sterns. Some people make small frames and ziptie the grass to it, some make a homemade tarp from camo leaf netting or similar and ziptie to that. 10-15lbs should be more than enough to build a good blind on a boat that size.