Help finding a through hull screw bearer for a blind hole

[Dave_S]

I don't think there will be such a thing but just in case.......

I hope to find something along the lines of a nutsert or rivnut for boats. The ones like shown are for sheet metal not for the thickness of the hull.

They will go on the back of the sugarscoopes to hold the kick up rudders in place and have water washing over them much of the time.

I need to be able to seal them off and screw in a minimum size of M8 screws.

[RaymondR]

Glass in a piece of stainless and drill and tap it.

[john61ct]

Put a stainless PlusNut into a stainless sheet, and glass that in.