I have an Autoprop on my Catalina 42. AB Marine had rebuilt the prop in 2007. In May of 2009 and 225 hours later a blade came off. Buntons Marine replaced the blade for $1500. I had it lubricated every six months. I am always in deep water. It never touched anything but saltwater. I only go to Catalina and back. Other than the lost blade there was not any evidence of damage or distress.
At the time Steve Armitage of AB Marine told me that losing a blade was a rare occurrence and that he did not have an explanation for why the blade fell off. David Sheppard of Brunton's Propellers Ltd, told me losing a blade is an “an exceptional case”. Contrary to their comments the prop has been subject to a recall for lost blades. If you search other support groups and blogs you will find many others that have lost Autoprop blades. It demeans their credibility to say otherwise.
Although I enjoy the performance of my Autoprop my experience with AB Marine and Brunton's Propellers has been extremely disappointing. They are unwilling to stand behind their product. In all their replies I feel like I am hearing from a politician trying not to give a straight answer.