Originally Posted by Shellback
Props should be designed for the hub to fail long before twisting the shaft. Would the manufacturer use a softer material for the shaft so you don't destroy the whole lower unit? I'd send those pictures to Powertech and find out if the hub should have failed before twisting the shaft. Don't know what to say about the big difference in spline contact area. You would think they should have designed the hub to fail first if reducing spline area.
PowerTech props have a cushion lock hub consisting of a bunch of ceramic(?) and rubber rods that are supposed to fail to prevent damage to the lower unit...you can see it here
The vendor is helping me out. Pictures are being sent to PowerTech to see what they say.