Hey Don,

I created recessed fittings with a hole saw, a spade bit and a gouge.

The rings were created by running the hole saw 1/2 way through the wood. I then used the hole created by the pilot bit on the hole saw as a guide for the spade bit to cut out the middle. Then, finish the cut with the hole saw.

These rings were simply trim pieces. The steel rod and the gouged out 'cups' are the real components of the fitting. Can't think of any easy way to install them without under-deck access.

http://alum.wpi.edu/~cmenard/cgi-bin/album/topics/Guillemot/MVC-008F.jpg
http://alum.wpi.edu/~cmenard/cgi-bin/album/topics/Guillemot/MVC-009F.jpg
http://alum.wpi.edu/~cmenard/cgi-bin/album/topics/Kayak/K-fitting1.jpg
http://alum.wpi.edu/~cmenard/cgi-bin/album/topics/Kayak/K-fitting2.jpg
http://alum.wpi.edu/~cmenard/cgi-bin/album/topics/Kayak/K-fitting3.jpg