So.... I'm now actually starting the build of my replacement rudder (reasons for which detailed in an earlier thread) and am wondering if others here can comment on a decision point I face:   1) I am going to use a 1.5" SS shaft for the rudder post (upgrading from the original 1.25" post) 2) I was planning on using NACA 0012 for my sectional shape 3) when I entered my chord length in a NACA foil calculator, I found that my new rudder would be approximately 2.8" thick at the location where the 1.5" post would be located.   Initially, I thought this might be a bit thin and wondered what it would look like if if bumped up to a NACA 0015 section. Using 0015 results in a rudder approximately 3.4" thick at the location of the post.   Am I correct to think I should opt for the extra thickness? What functional difference, if any, is likely between NACA 0012 and 0015?   Thanks,