+xI third antonkov and Hanaldo's larger nozzle suggestion - 2.5mm maybe. Sometimes you can thin gelcoat with styrene to get it to flow better through a spray gun but it's also asking for trouble. Are you spraying in one shot or multiple coats with time between? Do you gauge thickness? My understanding is that most alligatoring like this is caused by trapped styrene that comes from spraying too quickly over a just-gelled first coat. The rule of thumb I was taught it to wait until no gelcoat color comes off on your (gloved) finger when you lightly touch the surface before adding more - more gelcoat or a skincoat or laminate. I've certainly had it happen when this wasn't an issue and there are many contributing factors. Good luck and let us know if you have better luck after making some changes!
Thank you for the suggestions. I just bought the spray gun and the paint store recommended the 1.8. I will up the size to 2.5. Hanaldo, your correct, the 1.8 would not allow me to build up the Gelcoat. I was fighting thinnest. I do have the Gelcoat gauge to monitor my multi layer build to 22-25 mill. I miscalculated and did not order enough Gelcoat. I went ahead and applied the fiberglass to try and salvage my project. It came out decent enough that I will hand lay-up a hull so I can start designing the deck and cowl. I will start the process over. I apologize for not posting pictures. I want to keep this design a secret until I expose it at a National Event in 2021. I race gas RC Boats. Thanks for the guidance. Allen