How do I create a Cylinder with a hollow middle?

I know this sounds elementary but how do I create a cylinder with a hollow middle. I am designing a
propeller housing for a submarine and I cannot figure out how to do it in the script or with other primitive shapes.

You cannot do this in Unity, but if you download Blender from, or you can download it from the Steam store. (for free) Do make it hollow, make a cylinder, switch to edit mode, then select the circle faces, press delete, then press faces. That should hollow out the cube. Go into file, then click export, then export as OBJ. Open it in Unity, and this should work.