Hi MkI and Beurling;

MkI; Thanks for getting back to me about your PSRU and propeller. I was curious what level of confidence you have in these two units, overall. I guess what I revert back to is fear of the unknown, and vibration plus its effect on any mechanical unit are unknowns for me.

I also simply do not know who to trust when it comes to buying a PSRU. Company claims are simply too much like sales pitches, and often backed up with too little data to believe. Do Hy-vo chains really attenuate or dampen vibration? Not according to some manufacturers. But absolutely according to others that use these chains.

So I have been searching to find incidents of PSRU failures. I am trying to narrow my focus to spur geared units, not chains, helical gears and cogged belts, although I have found failure examples for all of those. I want to have some understanding of failure modes, and see if there is any common parts that seems to fail. So far, I have found that output shafts seem to snap and this has surprised me a bit, since I would have assumed that this would be a pretty beefy part. This would seem to suggest that it’s breaking due to tortional fatigue (don’t quote me on that) which in turn might indicate propeller vibration and power pulse issues from the engine. Perhaps these two vibrations are ganging together and making the forces bigger than predicted. You know, the propeller does its worst just as the engine does the same. I can kind of picture it, but this is pure speculation on my part. All I know is that PSRU’s are failing. Are they failing more often than props, engines???

Beurling; I’m surprised if there are belted units that handle 1000 HP. Thanks for letting me know. If you have any links on PSRU’s please share them, especially 400 HP + vendors.

I have tried to find the Camdrive vendor. Are they no longer operating?

Thanks guys, Tom.