Hi.
In 1922 JN bought a few british Thornycroft 55 ft coastal motor boats and tested them. After the tests IJA decided to build similar speedboats especially for scouting and communication purposes.
The scout boat was named "Kosokutai Ko" (speedboat version A):
length: 14,42 m
width: 2,74 m
displacement: 5,3 t
engine: 1 X gasoline, 400 hp
maximum speed: 37 kts
armament: none
Main purpose of this vehicle was high-speed reconnaissance just before the landings began to gather an actual view on surviving enemy equipment. Another pupose was fast transport of personell.
Total production number is unknown.
The smaller communication boat was named "Kosokutai Otsu" (speedboat model B)
length: 11 m
width: 2,43 m
displacement: 4,5 t
engine: 1 X diesel, 100 hp
maximum speed: 13 kts
armament: 1 X type 92 7,7 mm mg, 1 lmg
These boats were not real speedboats due to the limited maximum speed. Main purpose was building up communication lines by serving as central communication platform on company level during the early stages on a landing.
The boats were equipped with several wireless communication devices including optical (flags, morse lights, special optical communication devices).
A hmg could be mounted above the bridge and a lmg was also aboard.
Both speedboat types were introduced around 1930.
A special thanks to
Taki, who gives at least basic informations on these types of equipment on his website.
Yours
tom!
