A half inch is a pretty deep penetration in a 20-foot hull. You might have
somebody look at it to make sure you're not structurally effected.

*If* it's just cosmetic, throw some quick
patch stuff on it and use the boat until you can get the glass work done in the
slow season. *If* there's any possibility you're structurally compromised, I
wouldn't suggest using the boat prior to repairs.

Sometimes things that look small can turn out to be huge..........other times
we get lucky and things that look small really are.

If your hull is cored and the penetration has exposed the core, you should
certainly make a repair before using the boat again.