I agree with Tad.
One slip with a belt sander and you will cut a hole in the hull.

RE: Sanding
There are two different issues with respect to hull repair and sanding.
1. Smoothness or Surface Texture
This is controlled by the number of grit sandpaper or polish used to sand the hull.
You are trying to sand out scratches and small uneven areas and make it look and feel smooth.
A smooth hull is not necessarily a fast hull.

2. Fairness or Fairing
This controlled by the size(length) of the sanding block or sandpaper holder.
You are trying to take out the subtle highs and lows in the surface which cause turbulence.
I find the wallboard(sheetrock) sanding mesh and holder very good at this.
You should be able to sight down the hull and not see any uneveness or wavyness.

Generally you would Fair a hull first and then sand it smooth.

It is possible to have a hull that is Smooth, but not Fair and vice-versa.
The fastest hull would be both Fair and Smooth.