Most racers prefer a very tight fit, so it needs total physical rocking and pushing to go 95% in, then rubber mallet on base to seat.
Me, rec sailor, flatsand the sides so only finger rocking is needed to fully seat. I never have problems with it getting looser, but I only sail my slalom fins a max of 30 days a season, up to 15 seasons.

I disagree, you shouldn't have to force a fin in. (that also makes it harder to get out, and you can damage the board). It should be possible to have a neat snug fit without any play. But you have to be very careful sanding. If you aren't experienced it's more than easy to put a slight curve in the flat surface. There are also lots of inconsistencies in tuttle boxes and fins. If it's the ends jamming, make sure you sand them slightly concave, if they end up convex it's easier for the fin to rotate.

Ha ha.....
Used to hang around World Cup and local races.
Always fun and disturbing to see a 6'2", 205 lbs., 23 year old fit racer spend 3 minutes struggling to install a 40 cm fin. One foot on the upside down board, one hand padded, 70% strength and leverage, rubber mallet and wood blocks nearby.

This guy has a good video on fitting.

decrepit said..
I disagree, you shouldn't have to force a fin in. (that also makes it harder to get out, and you can damage the board). It should be possible to have a neat snug fit without any play. But you have to be very careful sanding. If you aren't experienced it's more than easy to put a slight curve in the flat surface. There are also lots of inconsistencies in tuttle boxes and fins. If it's the ends jamming, make sure you sand them slightly concave, if they end up convex it's easier for the fin to rotate.

Agree if it fits it not going to wobble even if it go in easy.
if your having to lube it then it's to big and need sanding, it's not any more solid in the box just because it's tight to get in.

Thanks for the feedback. I was able to get the fin installed. I did a very light sanding with 220 grit just on key areas where I could see scuff marks on the side. I also felt inside the box (Falcon Slalom TE) and could feel a couple rough spots. Some left over reason maybe? I sanded those back as well. It was still very tight but It was no more tight than what some of you described earlier in the pro world. I guess when the fin is very tight the vibration/flex of the fin is transferred to the board more for better feel and feedback? Is that the idea why the pros seem to like such a tight fin fitment?

Lubing a fin will attract sand and salt which will wear the fin and box . Wiping the grit off the fin is easy but not in the box . Sounds like a bad idea to me .
A dry lube like graphite would be ok but ugly .