Volkswagen Schwimmwagen

With 15,584 built between 1941 and 1944, most of them at the Volkswagen works in Fallersleben, the Type 166 is usually counted as the most-produced amphibious car in history. It earned those numbers by being simple: a small air-cooled engine of 1,131 cc, four-wheel drive in first gear, and a propeller that the driver swung down from the rear on a plain iron rod before entering the water. That simplicity was the point. The first examples went to units on the Eastern Front and proved their worth in marshy ground, where a light car that could cross a river without waiting for a bridge mattered more than speed afloat. It is the clearest case on this list of a small amphibian built in real numbers.