If the cracks are not at a bulkhead/locker divider, under the forward berth, it is likely you have a minor impact damage. The circular shape would be consistent with an impact. The hull will have flexed and the gelcoat, being the weakest part of the structure will have cracked.
    I had some gelcoat cracking on my B34 at the aft bulkhead, just below the waterline.
    I used the corner of a tungsten scraper to open out the cracks and check that the damage was only in the gelcoat. I then filled the cracks with an underwater gelcoat filler and finished off with fine abrassive paper. The problem above the waterline is getting a match. There are more shades of white than colours in a rainbow, but it is most important to stop water entering the cracks in the gelcoat and reaching the underlying structure.
    Before i started to open up the damaged area I used plenty of masking tape to protect the adjacent gelcoat as it is not easy to follow the cracks and I found that a light hand was necessary until a small V had been established to guide the scraper.