The German trawler V 406 Hans Loh was a steam trawler that became a Vorpostenboot (patrol boat) in the Second World War. She was launched in Germany in 1936 as Hans Loh. In September 1939 she was converted into the Vorpostenboot V-402. That October she was renumbered V-206. A mine sank her in the Gironde estuary in August 1942, killing 18 members of her crew.
In 1936–37 Deutsche Schiff- und Maschinenbau (DeSchiMAG) built a pair of trawlers at its Seebeck shipyard in Wesermünde, Bremerhaven for the fishing fleet of Grundmann & Gröschel. Yard number 560 was launched as Franz Dankworth, and completed in 1936. Her sister ship was built as yard number 565; launched on 23 November 1936 as Hans Loh; and completed on 7 January 1937.
Hans Loh had the same specifications as Franz Dankworth. Her registered length was ; her beam was ; and her depth was . Her draught was . Her tonnages were and . She had a cruiser stern, and a single screw. She was equipped with wireless direction finding, and an echo sounding device.
DeSchiMAG also built her engines. Her main engine was a three-cylinder triple-expansion engine. It was supplemented by an exhaust steam turbine, which drove the same propeller shaft via DeSchiMAG's patent Bauer-Wach system of a Föttinger fluid coupling and double-reduction gearing. The combined power of her reciprocating engine plus exhaust turbine was rated at 96 NHP, and gave her a speed of 12kn.
Grundmann & Gröschel registered Hans Loh at Wesermünde. Her port letter and number were PG 509,[1] and her wireless telegraph call sign was DFCQ.
The Kriegsmarine requisitioned Hans Loh on 17 September 1939; had her converted into a Vorpostenboot, and commissioned her as V-402. She served in the 4. Vorpostenflottille ("4th Patrol Boat Flotilla"), which operated in the North Sea. On 16 October 1939 she was renumbered V-406. After France capitulated to Germany, the flotilla was transferred to the Bay of Biscay; mainly Bordeaux and Bayonne.[1]
On 18 August 1942, V-406 steamed north up the coast from Arcachon to Royan with and . As the three trawlers entered the Gironde Estuary, V-406 struck a mine that the had laid, and sank at position 45.0333°N -33.7°W. V-411 rescued 24 members of V-406s crew, but one died shortly afterward. V-411 landed survivors at Royan.[2] In total, 18 members of V-406s crew were killed.