Builders of the Most Versatile Vehicle Ever Built. Based on the legendary Humvee, the H1-Panther is the most versatile vehicle ever imagined. This is WaterCar’s fifth, and most advanced amphibious model to date. Built to withstand the most brutal conditions, from the roughest terrain to the most challenging water conditions. The H1-Panther pushes the boundaries of what’s possible. It is a true Amphibious all-terrain utility vehicle that can achieve highway speeds and cruise at thirty-five knots on the water.