British U-class submarine
The British U-class submarines were a class of 49 small submarines built just before and during the Second World War. The class is sometimes known as the Undine class, after the first submarine built. A further development was the British V-class submarine of 1942.
U-class submarine HMS Ultimatum departing Holy Loch, August 1943
British V-class submarine
The British V-class submarine was a class of submarines built for the Royal Navy during the Second World War.
HMS Voracious