I got tired of water coming into my kayak from the scupper holes. They drained fine but when it was windy and there were waves water kept splashing in, so I designed this simple scupper plug that has a floating ball check valve. If water gets in from the paddle or over the side it easily flows out but no more splashing in through the scupper holes. Give it a try and give me some feedback. It can always be made better so suggestions are welcome.

You may want to print the plug itself with ninja flex to allow it to seat in the hole better or you can simply epoxy them in.

Note: For assembly, epoxy the the grate to the scupper plug after putting the ball in side and it works pretty well.