Nice solution John. How much does the 400 mm SS rod cost and where do you get it?
Hard to say the exact cost of the shaft. I had it made up along with some other modifications to my tension leg pier.
I can say that stainless 316 bar of 25mm diameter is around $80 per metre, and weighs 3.9kg per metre. Your local steel supplier should be able to get it in for you.