Repainting storyboards question

[Bob Quinn]

I have these storm boards and the paint has a weird cracking in it that is very deep.I thought I could sand through it but it's proving to be very thick hard paint.What are my options? Would primer fill this in or do I have to sand right down to the fiberglass?Thank you

 

[SEVEN]

The surface is delaminating from the base. You can sand it down and then use fairing compound, then primer and then finish.