Can anyone clarify something for me?  I have the stitch and glue boatbuilding book with the guidance on an Oxford shell.  I also purchased the dedicated plans to build an Oxford shell. The materials lists in each source don't match though. The book states that I need 2 sheets of 4 mm plywood and one sheet of 3 mm, while the plans state I need 2 sheets of 3 mm plywood and one sheet of 4 mm.  What gives?  I drove 3 hours to the nearest source of BS1088 and picked up all the materials, but it looks like I might have a problem....