my first print in cura without support
Thanks for sharing this image of the #3DBenchy. It appears that you have uneven filament feed and maybe also cooling of the filament (if you are using PLA) will improve the shape stability of your print.
Our advice is to try again with "thick layers", 0.3 mm and print a slow speeds. Make sure you have a fan that blows cool air on the 3D-printed boat.