The purpose of the scupper hole is to allow water that splashes on to the deck to drain back out and not pool underneath the paddler. Blocking these holes will keep tiny splashes from coming up from underwater through the holes but it will keep any water that makes its way onto the deck from draining back out.
Scupper holes, found in sit-on-top kayaks, are designed as a safety feature to drain water out of the kayak, from top to bottom, which keeps you from sitting in a puddle or even worse, making your kayak a bathtub full of water prone to capsizing.
What are kayak scupper plugs for?
Kayak Scupper Plugs recently launched an innovation in plug design, our self-draining or self-bailing scupper plugs. These plugs are able to block water from coming up from the bottom of the kayak through the scupper holes while still allowing any nuisance water that splashes inside to drain away freely.