Surfing Waves

I bought a used board and noticed there was a scratch near the fin. Does this need to be repaired or is it not deep enough?

I'm not sure what to say about this but if it was my board I would have the fin box removed and reglassed and reset. It looks like maybe someone tried to fix that superficially or not but anyway looks like the fin hit something hard and the fin box was partially tore out and I am guessing unless you remove and reglass it this will be likely take much less force to do even more damage. Disclaimer is I haven't ever had this problem so it's just a guess.

You didn’t see that before you purchased it ? It needs to be at least glassed over. Since water is now able to get it ( or maybe already has if the previous owner got the hit in the water ).

How much did you pay for the board ?

Take the fins out and suck on the crack, is there air coming through?
If so grab some fibrefill, it has served me well as I got a very performance glassed board so cracks easily, use some sanding paper after and even if you can still see it it will have a layer of resin stuff in it. Phix Doctor is what I use.

I agree with Waikikikichan. It's not a scratch, it's a crack in the resin/glass. I also see what looks like 2 different tones of white, or shadows if you will, which could be some delamination? Maybe not but it's worth having it looked at. I've found surfboard repair shop prices to be more reasonable than anticipated, and having it looked over by someone who sees this stuff day in and day out is comforting.

This happened to my wife’s board last year.