My daughter finally took her kayak out of my basement. It is actually an inflatable one so doesn't really take up any room but she has a lot of her stuff down there. Anyway, it is an easy way for her to go still water fishing and relaxing by herself. Until she said she had to rethink a few things. I thought she was talking about fish hooks in a rubber boat. She said, No, it was the breeze. ? First off, there is no cell service where she goes. Second, there is no anchor on a kayak. The slightest breeze can move her about the lake. She was lucky the last time to still be in shallow water. She likes to watch the fish in addition to catching them. But on a day where the breeze became a bit more, she had trouble keeping up with it. She finally tied herself to a pond lilly with fishing line to be sure to stay near her intended position. Fun and danger in everything.
When I was a kid we had a styrofoam boat with a sail. The thing was hyper-buoyant and sat way up on the water. If there was enough breeze to catch the sails, it was gonna be even more effective on that big foam tub. As a kid, I've been caught in a storm in it...paddling is futile. My sister and a friend came this close |-| to being swept out of a small bay and into the Atlantic on the currents. There are some things that are just really, really bad ideas. Foam boats and inflatable boats are close to the top of the list.
Tell her to sell the kayak and get a small canoe if she wants to do fishing on a lake. If she is in fast-moving water and shooting rapids for fun, the kayak would be the better choice. A canoe with a small keel and a low bow and stern will allow her to paddle in a straight line on a lake, and she can carry a lot more stuff in the canoe...including an anchor and rope.