The Sea-lect Designs Plastic Inspection Plate can be used to close unwanted openings in your kayak. The Sea-lect Designs Plastic Inspection Plate is also sometimes used during rudder installations on some Ocean Kayak brand kayaks.
|Int. Dim.:||4 9/16"|
Just buy a 4" port. This is just as much work to install and a lot more work to reopen.
It's a round piece of plastic with screw holes, nothing more, nothing less. For me, I bought what I wanted and it is exactly what I needed.