Hi Emerald Sea,
I finally made a decision to install the Sd60's based on the uncertainty of when the re-lapped cones would again fail & the continuing cost.My research
indicated that the cones really needed to be replaced & then lapped to bed
them in if one wanted to do the repair properly, so repair can be expensive. It was indicated that, particularly with charter
yachts, re- lapping was part of the annual service
With the change over, an adaptor plate is needed with my engines ,39hp 3JH5CE's. Also there is a small variation in gear ratios between the 50 & 60 & at the moment at full revs I exceed 3000rpm which requires a slight increase in prop pitch
which can be easily done in water
with my Autostream props.I'm relying on the fact that the plate clutch doesn't have the same problems which seems to be the case as it's used in other brands of sail drives,time will eventually tell.I hope this helps, good sailing.