kuchiku-tei ka-ro
A series of motor gunboats used by the Imperial Japanese Army during World War II.
The Ka-Ro type 4 (カロ艇第四型式 aka. 四式四型駆逐艇/Type 4 (Mod 4) Kuchiku-tei) was a special model equipped with air-propellers. It was never actually used in warfare.