I am trying to find a better way to sand the inside of canoe and kayak hulls. I am working on a "Rob Roy" right now and sanding the inside by hand with a foam block with sand paper wrapped around it. This is very effective, however, my arms are sure getting tired!!

I used a Dewalt Random Orbital on the outside and this worked very well, as you can "roll" the flat sander to match the curve of the outer hull. This totally does not work on the inside.

Any suggestions on technique and/or tools would be greatly appreciated.

Stephan