A Thunderbird is also a 26 foot long sailing vessel. The hull is made of plywood with a fiberglass shell at least as high as the waterline. My dad had a Thunderbird hull which he built onto, to make the sailboat of my childhood. It had an open cabin with four bunks, a kerosene stove, cooler, and pump toilet, and not much else. We used it to sail around the Gulf Islands in British Columbia. Times on that boat yielded some of my most cherished memories, those halycon summer days of sun, ocean, family, innocent pleasures and joys.