Making a Ship's Helm From Scrap Timber.
Step 1: making rings for front, back and centre
make two rings and two centres from plywood.Use a large size compass ( I made one for an earlier project ) and scribe two set of concentric circles. Outer diameter is 600mm, inner diameter is 400mm. This plywood is 3mm thick. Dont worry, it is quite robust !!
Now make two circles for the center. These are 155mm diam. Please don't ask why. I was winging it.