This is a mod that I implemented to my Pelican Bass Raider 10e which allows a 3d printed shim(s) to be placed inside between the upper and lower deck of the hull after drilling with the hole saw. The purpose of this shim is allow the scupper drain, after insertion, to be properly secured when it is tightened down by the drain nut and not deform the hull surfaces.
3D PRINT FILES: https://www.thingiverse.com/thing:4775154
DRAIN PLUG: https://amzn.to/2Pclehx
DEEP CUT HOLE SAW: https://amzn.to/3pTowTs
5200 MARINE SEALANT: https://amzn.to/3qTfuat
THRU-HULL DRAIN: https://amzn.to/2ZP5xii