I looked at a picture of my rudder posts on my cat. Looks like they were about 1.5 inch in diameter as well. It also appears like the issues may have been more with the internal framework spinning inside the foam/glass rudder blade. Whether the 1.5 is undersized or not, just comparing the workmanship/materials between mine and the Alpha, I must say the Alpha does look, umm, 'more economically built' perhaps. I also had solid tie bars directly linked to the helm and which could be individually disconnected from the system if there were issues.