A transparent and shark-repelling surfboard or flotation board made of transparent super microcellular polymer foam with transparent coating. The surfboard or the flotation board has a locater device for locating large aquatic animals, and an alarm device for alerting a rider of large aquatic animals, such as sharks, located by the locater device. The surfboard or the flotation board also comprises a repellent or deterrent signal generator that is configured for transmitting interference signals to disrupt the electro-sensory perception system of the aquatic animals.