China recently announced the decommissioning of "Submarine 303." This was a Type 33 boat (a copy of the Russian Romeo class). Romeo was the successor to the Russian Whiskey class boats, which were, in turn, based on the German Type XXI. The German design first showed up in 1943, and was the first modern submarine, in that it was designed to spend most of its time underwater (with just the snorkel device and periscope above water, to bring in air for the diesel engine and crew). The Type XXI was a 1,600 ton (on the surface) sub, compared to the...
