How deep are the stress cracks? Do the cracks go into the FG cloth or are the just in the gel coat? Did they develop slowly over time or all of a sudden? It is not uncommon for cracks to develop in the gel coat around corners of widows, joggled areas and shaper radius areas. This happens when the gel coat is applied too thick and even a small amount of vibration or twisting of the frame can cause the gel coat to crack. Without seeing your issue, I am guessing this is what you have. If the crack extends in the FG and the FG is cracked or you see broken fibers that is a more serious issue, but I would think you would have felt this.