The scupper without a bulkhead is so simple. You drill a hole in the back of the ski, glue a scupper in, and you're done. No PVC pipe, no special fitment, no drilling foam, etc. I have considered sticking some polyethylene back in the gunwales but at the same time, I don't know if I could get enough in there to even keep the ski afloat anyway. One day when I'm bored, I'll try to measure the volume back there. One sheet of polyethylene will float 60 lbs and I couldn't get a full sheet in my flatdeck SN but that was a flatdeck. Maybe I could get 3/4 to a full sheet in this ski but it's shorter and I would still need to keep the scupper drainage in mind. Maybe coke bottles...maybe air bladders...maybe some of the other crazy stuff people brainstorm about but never try.