I notice that you haven't answered my questions or posted any pictures.It would have to be massively bigger than it is, or than is practical, to come even close.
A hydrovane is still a blade supported from only one end ( cantilevered).
Perhaps the problem is that I have crossed oceans in steel built and GRP boats and the way that I question your assertions is uncomfortable for you?
PS I sleep extremely easily when I am at sea in a well built GRP boat.
PPS The last steel boat I sailed is currently being cut up for scrap. This despite many tens of thousands of £ spent on her up keep. Eventually corrosion just became too much. That boat had been round the world at least twice. And you wonder why so many people find your assertions about steel boats and wind vanes etc etc problematic?