Troubles with Nacra 5.8s

I have three Nacra 5.8s used in a camp setting with kids sailing them almost every day of the summer and I am not very well versed in fixing Nacras. I'm having a lot of trouble with the halyards. The part of the mast from which i pull the halyard down to hoist the main is super sharp and keeps shredding our halyards. we have replaced 4 in the past 3 weeks and they are impossible to pull up and get the ring on the hook when the halyard is shredded.

i was thinking of purchasing a Nacra 5.7 halyard with the shackle from Murrays to see if the designated Nacra line is better than what we are using but i dont know if the Nacra 5.7 halyard will fit our 5.8s. Any help would be much appreciated! Halyard line suggestions? Ways to de-sharpen the mast hole? Better ways to raise main?

Thanks,
TBYCats
The earlier 5.8s had the halyard coming out of the mast track a few feet up the mast
I never had that issue
Can you take a round file and clean up any spurs that may be there