More good questions, all of which I have been thinking about. I think that Yara stole supplies along with ships from the Iron Islands. She was stealing the best ships anyway -- why not also steal food. As for months to sail to Dragonstone, I saw nothing that suggested that it took months. If you look at the maps, crossing the Narrow Sea was a short distance. https://www.google.com/search?q=map+westeros&tbm=isch&imgil=OpV1eyDE6zSFHM%253A%253BLe0L_MCjPCDbkM%253Bhttp%25253A%25252F%25252Fawoiaf.westeros.org%25252Findex.php%25252FKnown_world&source=iu&pf=m&fir=OpV1eyDE6zSFHM%253A%252CLe0L_MCjPCDbkM%252C_&usg=__AJQUXg6XCdW1FAsK6uLHOYinP5Y%3D&biw=1920&bih=947&ved=0ahUKEwjUk8zvr8nVAhVK9GMKHcHLBHkQyjcIRw&ei=e5eKWZTqKcrojwPBl5PIBw#imgrc=OpV1eyDE6zSFHM: What bothers me the most was how easily Euron's fleet beat Yara's fleet. Yara supposedly took the best ships. My best answer is that in his travels Euron discovered ways to build better ships and use fireballs. Still, I was very disappointed by Yara and her fleet -- in wrestling terminology they were "jobbing" for Euron to build up his "heel" status.