BETASOM (an Italian language acronym of Bordeaux Sommergibile) was a submarine base established at Bordeaux, France by the Italian Regia Marina Italiana during World War II. From this base, Italian submarines participated in the Battle of the Atlantic from 1940 to 1943 as part of the Axis anti-shipping campaign against the Allies.
Axis naval co-operation started after the signing of the Pact of Steel in June 1939 with meetings in Friedrichshafen, Germany, and an agreement to exchange technical information. After the Italian entry into the war and the Fall of France, the Italian Royal Navy established a submarine base at Bordeaux, which was within the German occupation zone. The Italians were allocated a sector of the Atlantic south of Lisbon to patrol. The base was opened in August 1940, and in 1941 the captured French passenger ship De Grasse was used as a depot ship before being returned to the Vichy French Government in June 1942. About 1,600 men were based at BETASOM.
The base could house up to thirty submarines, and it had dry docks and two basins connected by locks. Shore barracks accommodated a security guard of 250 men of the San Marco Regiment.
The base was bombed by the British on several occasions, especially in 1940 and 1941, but no significant damage was suffered, except for the sinking of the barracks ship Usaramo. The base was indirectly attacked by Operation Josephine B in June 1941, a raid to destroy the electricity substation that served the base.
The last two remaining U-boats left Bordeaux in August 1944, three days before the Allies occupied the base on 25 August. The last remaining German naval personnel attempted to march back to Germany but were captured by US forces on 11 September 1944.
The submarine pens have proved to be infeasible to demolish due to their massive reinforced construction which had been designed to withstand aerial bombardment. In 2010, after conversion several years previously, approximately 12,000 m2 of the 42,000 m2 building were opened to the public as a cultural centre for the performing arts, exhibitions, and evening events.
References:Vufflens castle was built in 1425 on the site of a previous medieval castle by Henri de Colombier. It is the most significant example of a small group of fortified Romandy castles from the middle ages, characterised above all by its brick construction. In 1530, it was set on fire by Bernese troops. In 1641 it was acquired by the de Senarclens family. The castle is currently privately owned and cannot be visited.
A pleasant 30 minute-walk through the vineyards between Vufflens-le-Château and Denens, offers a stunning view of this magnificent castle, the lake and the Mont-Blanc.