I had read several posts in this group regarding the Hydrovane self steering unit. It surprised me because I know several owners who have had stellar experiences with them. Close friends of mine used one for their circumnavigation and used it virtually 100% of the time off shore--including over a 10 days in the Indian Ocean where they mostly would not even venture into their cockpit--sounded awful...anyway, I cut and pasted some of the content of our postings to them and asked for an explanation and received the following.
"We would expect a Hydrovane on your boat to give the same excellent performance that you have heard from others see the HEAVY BOAT section of our website at http://www.hydrovane.com/OurProduct.html
scroll down about 3/4 of the way down the page. There is no reason why an Amel would be different than any other boat
. and your Santorin does not even qualify as a `HEAVY BOAT' in our lexicon. The Hydrovane is indifferent to the boat it is fitted to. It will produce its certain amount of steering power for any boat.
For those boats from which you have heard of Hydrovane problems: The time frame of those issues was after we introduced our new rudder. It took us 2 years including tank testing of the rudder at the University of Southampton to finally discover the problem some of the rudders were `wonky'. In technical terms we had the shaft hole position of the rudder too near its perfect balance point. When it is perfectly balanced the rudder no longer knows which way is forward. Actually the shaft hole line (projecting the shaft hole to the bottom of the rudder) was too close or maybe even crossed over the COP (Centre of Pressure) of the rudder in the upper half. Worse was the discovery that if the shaft hole direction was as little as a half degree out in the wrong direction the rudder could be unstable. We now believe that both reports you heard were probably bad rudders. See TIPS #7 POOR PERFORMANCE at: http://www.hydrovane.com/Tips.html#7
for our description of the problem and a `recall' of any such bad rudders. The confusing part for us was that so many of those rudders were good performers but not all of them. In hindsight those other Amel s with problem Hydrovanes only needed a new rudder with a shaft hole in the right position."
Anyway, this may be helpful info for some of you.
Santorin 86, Brittany de la Mer