Hey Ya'll
I recently finished doing a broken mast and sprocket replacement around three weeks back or so.
The end of my mast broke above the sprocket and left the stub of the broken mast stuck in the sprocket hole. When I was trying to remove the stub it wedged down deeper into the sprocket and then there was no easy way to remove it.
I tried to drill it out then my drill bit slipped and put a hole in the sprocket which meant I now had to replace the sprocket as well as the broken mast. The funny thing was the sprocket had sustained no noticeable damage even though my trailing fin had probably smashed into an old pier post underwater and snapped the mast right off . There was no split or any other noticeable damage to my sprocket which I thought was odd..

Here's the picture..
Anyway the point is I was beginning to notice that after every outing the fins and mast were loose as the set screw kept backing out from the fins twisting the mast back and forth in the hole I guess. So I would tighten them up again before the next trip but the end result was the same..loose lucy and goosey fins and mast when I got back. So I started to look at a fix for this dilema because I could see this was starting to hog out the sprocket hole and so I wound up taking out all the set screws in our tandem mirage drive ( 4 each) and coating the threads with "Blue" Loktite.
Im happy to report that the mast and set screws seem to be still tight and snug after 6 or 7 trips so far. I would suggest anyone try this little fix if they notice the loose mast and set screw problem and even if they dont, try it anyway just in case.
......... Worked for me...Have fun........ Happy Fourth
. Kepnutz