Submarine pen
type of submarine base that acts as a bunker to protect submarines from air attack
A submarine pen (U-Boot-Bunker in German) is a type of submarine base that acts as a bunker to protect submarines from air attack.
The term is generally applied to submarine bases constructed during World War II, particularly in Germany and its occupied countries, which were also known as U-boat pens (after the phrase "U-boat" to refer to German submarines).
Background
Among the first forms of protection for submarines were some open-sided shelters with partial wooden foundations that were constructed during World War I. These structures were built at the time when bombs were light enough to be dropped by hand from the cockpit. By the 1940s, the quality of aerial weapons and the means to deliver them had improved markedly.
The mid-1930s saw the Naval Construction Office in Berlin give the problem serious thought. Various factions in the navy were convinced protection for the expanding U-boat arm was required. A Royal Air Force (RAF) raid on the capital in 1940, the occupation of France and Britain's refusal to surrender triggered a massive building programme of submarine pens and air raid shelters.
By the autumn of 1940, construction of the "Elbe II" bunker in Hamburg and "Nordsee III" on the island of Heligoland was under way. Others swiftly followed.
General
It was soon realized that such a massive project was beyond the Kriegsmarine, and the Todt Organisation (OT) was brought in to oversee the administration of labour.
The public source identifies “Submarine pen” as type of submarine base that acts as a bunker to protect submarines from air attack. This brief keeps that definition visible, then builds a research path around Submarine, type and submarine.
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This entry incorporates text from “Submarine pen” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.