Just to be clear, we are talking about Volvo folding props and Volvo saildrives? My response below is based on this.
We just replaced a folding prop because of teeth wear. The old prop was 11 years old and had 1700 hrs on it. I think a contributing factor was my having the yard sandblast it to remove the old primer and paint
. I didn't notice the worn teeth when I gave it to them (and the prop worked fine) but there was significant loss of metal and pitting on the teeth after and the prop blades would slip when opening/closing and not work properly. I know of two other boats with worn prop teeth after ~8 years and many hours, but one was directly contributed to stray current
in a marina (lots of damage besides the props).
The saildrives and folding prop combination have been in use together for many years across the globe without incident, and the props have also been used on Yanmar
saildrives, so I don't think the props are responsible for the transmission damage. More likely is that the blades did not open evenly because of the worn teeth and the resulting unbalance did the damage. If this was the case, I would expect water
in the oil
due to worn lip seals
and possible bearing damage. Or gear damage caused by these. What type of damage did you find?
I agree it shouldn't be happening with the age of your props and number of hours. How did you rule
? Can you post a picture of the gear teeth?