B-class motor launch
 Launch of Cha 105 in Soerabaja.
| |
| Class overview | |
|---|---|
| Name | B class |
| Builders |
|
| Operators | |
| Planned | 16 |
| General characteristics | |
| Type | Motor launch |
| Displacement | 130 t (130 long tons) |
| Length | 45.5 m (149 ft 3 in) |
| Beam | 5 m (16 ft 5 in) |
| Draft | 1.4 m (4 ft 7 in) |
| Propulsion |
|
| Speed | 19 knots (35 km/h; 22 mph) |
| Armament |
|
The B class was a ship class of sixteen motor launches built in the Dutch East Indies for the Royal Netherlands Navy.[1][2] However, before the motor launches could be completed the Dutch East Indies was invaded by the Japanese.[3] To prevent the vessels from being captured they were scuttled.[4] Nonetheless, seven motor launches were salvaged and completed as auxiliary submarine chasers by the Japanese and taken into service of the Imperial Japanese Navy as the Cha 103 class.[2][5]
Design and construction
The B-class motor launches were built in the Dutch East Indies at the shipyards of Droogdok Maatschappij Soerabaja, Marine Etablissement te Soerabaja and Indische Maatschappij Palembang.[4] They were designed to be able to perform various roles such as auxiliary submarine chaser, patrol vessel and auxiliary minesweeper.[6] The launches measured 45.5 metres (149 ft 3 in) in length, had a beam of 5.0 metres (16 ft 5 in) and a draft of 1.4 metres (4 ft 7 in).[4] Furthermore, they had a displacement of 130 tons and were equipped with diesel engines that could produce 1,900 brake horsepower (1,400 kW).[7] This allowed the launches to reach a maximum speed of 19 knots (35 km/h; 22 mph).[7] As armament they had a single 76-millimetre (3 in) naval gun, a single 40 mm (1.6 in) anti-aircraft gun, two 12.7 mm (0.50 in) machine guns and 20 depth charges.[4][2]
Cha 103 class
The seven motor launches that were salvaged and completed as auxiliary submarine chasers by the Japanese became known as the Cha 103 class.[2][5] These submarine chasers were equipped with different diesel engines and armament in comparison to their original B class design.[8] Four chasers (Cha 103, Cha 105, Cha 107 and Cha 108) were equipped with diesel engines that could produce 1,800 bhp (1,300 kW), which allowed them to reach a maximum speed of 20 knots (37 km/h; 23 mph).[8] Two (Cha 114 and Cha 115) were equipped with diesel engines that could produce 1,500 bhp (1,100 kW), which allowed them to reach a maximum speed of 19 knots.[8] While the last one, Cha 106, was equipped with diesel engines that could produce 1,200 bhp (890 kW), which allowed the chaser to reach a maximum speed of 16.5 knots (30.6 km/h; 19.0 mph).[8] All auxiliary submarine chasers of the Cha 103 class were armed with a single 47 mm (1.9 in) Yamanouchi gun, a 13.2 mm (0.52 in) machine gun, a 7.7 mm (0.30 in) machine gun and two depth charge rails that could carry a total of 32 depth charges.[5]
References
- ^ Lenton (1968), p. 95.
- ^ a b c d Gardiner and Chesneau (1980), p. 396.
- ^ von Münching (1978), p. 116.
- ^ a b c d Mark (1997), p. 137.
- ^ a b c Vermeer, Wilco (9 February 2025). "Japanse Onderzeebootjagers van de Cha 103-klasse (1942)" (in Dutch). TracesOfWar.com.
- ^ von Münching (1978), p. 8.
- ^ a b von Münching (1978), p. 115.
- ^ a b c d Lenton (1968), p. 96.
Bibliography
- Gardiner, Robert; Chesneau, Roger, eds. (1980). Conway's All the World's Fighting Ships 1922–1946. London: Conway Maritime Press. ISBN 0-85177-146-7.
- Lenton, H.T. (1968). Royal Netherlands Navy. Navies of the Second World War. London: Macdonald & Co.
- Mark, Chris (1997). Schepen van de Koninklijke Marine in W.O. II (in Dutch). Alkmaar: De Alk. ISBN 90-6013-522-9.
- von Münching, L.L. (1978). Schepen van de Koninklijke Marine in de Tweede Wereldoorlog (in Dutch). Alkmaar: Alk. ISBN 90-6013-903-8.