is not for strength but for longevity. Crevice corrosion will weaken a tube long before it will weaken a sold shaft. Secondly, I said Aquamet 22 because of it's corrosion resistance.

Many years ago I saw a rudder shaft pulled from a Gulf Star that was badly pitted and streaked with rust. Mine (thank you original Nordic Yachts) was bright and shiny three years ago when I pulled it to replace the bearings.