Creating an amphibian is not an easy task. It is necessary to find the perfect balance between the car and the boat. The amphibian of the Soviet engineer Yuri Chumichev was one of the very first home-built vehicles of this type. The author called it the ‘Katam’ — the mix between a boat and a car.
Yuri Chumichev manufactured the Katama’s hull according to the technology adopted for the construction of boats — a wooden frame sheathed with plywood impregnated with waterproof materials. Moreover, Chumichev worked out the shape of the hull by testing a scale model on the water, and he documented the entire testing process in the best traditions of design reports with drawings, diagrams and graphs.
As a result of this work, the author of the amphibian achieved minimal water resistance. Chumichev borrowed the two-cylinder engine and rear wheel suspension assemblies from the Java-350 motorcycle. A four-speed gearbox and transfer case transmitted torque to the wheels or propeller.
The undercarriage units were taken from the S3A motorized carriage, but unlike it, brakes are installed on the front wheels. The steering column and gearbox are from Moskvich-402. The amphibian was equipped with light signaling devices adopted in the river fleet and was registered not only as a car, but also as a small vessel.