M_Boats: Centerboard Line "Burp" Leakage

I have been sailing mynew to me 1977 Seranita M17 for the past three days here in San Diego. I have noticed a weird quirk...the penetration hole for the line that lowers the centerboard "burps" during sailing and shoots water intermintantly into the cabin sole. Any ideas or experience as to how to tackle this? Is this a common thing for the older boats? Best, JB 1977 M17 "Serenita" San Diego, CA