U-boat
German Unterseeboot -- the English word for 1914-45. Ancestry or first type-name of Submarine -- history of a class, not a build list.
Historical U-boat arms, Allied escort groups, US SubPac, later SSBN forces -- past structures.
Not a current patrol map or a ROKN order of battle.
Systems
Unrestricted submarine warfare
Attacks without prize rules -- a legal-political choice.
Wolfpack (popular)
A later English label for grouped U-boat operations -- historically named, not instructed.
Nautilus
First nuclear-powered submarine, 1954. Treaty, crisis, or doctrine caption -- not a launch or employment guide.
John Philip Holland
An early practical-submarine name in English and US histories.
Pacific tonnage
A logistic decision.
Meters
Atlas scale (not a war)
40
Peak intensity
38
How long it defined a period
80
Doctrinal / technical shift
84
Borders, regimes, law, alliances
58
Film, school, ritual density
56
Hotspots
First U-boat war
1900-18: Law and food. Named as historical geography of Submarine, not as a targeting list.
Treaty and rearmament
1919-39: Limits and cheats. Named as historical geography of Submarine, not as a targeting list.
Second U-boat / Pacific
1939-45: Tonnage wars. Named as historical geography of Submarine, not as a targeting list.
Nuclear / SSBN
1954-91: Deterrent type. Named as historical geography of Submarine, not as a targeting list.
More operators
After 1991: ROK KSS; accidents as memory. Named as historical geography of Submarine, not as a targeting list.
Materials
Chronology (1900s-present (as a war type; ancestors earlier))
Submarine is bounded as 1900s-present (as a war type; ancestors earlier). 1900s opens the usual narrative (Holland boats); 2000-08-12 closes it (Kursk sinks).
Theatre: Atlantic 1914-45, Pacific 1941-45, then a nucle.
Place is evidence. Atlantic 1914-45, Pacific 1941-45, then a nuclear-deterrent undersea is where Submarine happened -- a map for readers, not a guide for repeating it.
Human-cost band
not a war -- merchant and navy dead sit on U-boat and Pacific war ledgers Keep the figure as a range. Spectacle integers are not a census.
Wolfpack (popular)
A later English label for grouped U-boat operations -- historically named, not instructed. A material of the Submarine vocabulary, dated to 1900s-present (as a war type; ancestors earlier).
No sonar, no approach, no escape-trunk content.
Convoy is named as a 1917/1943 reply that worked.