This is coolbert:
Yet one more listing, "Top", "Best", as usual thanks to The National Interest and the article by Mr. Robert Farley.
"The Five Best Submarines of All Time"
"As with previous '5 Greatest' lists, the answers depend on the parameters; different sets of metrics will generate different lists."
Ranking and listings dependent on "metrics and parameters", each expert generating his own set of "metrics and parameters". Ten different experts and expect different listings and rankings.
* That German XXI electric-boat of the Second World War [WW2] according to a prominent German submariner would not have been a war winning measure. That ability of the XXI to operate for long periods under-water without surfacing negated the possibility of "wolf-pack" type attack which constituted the most successful German submarine tactic of the war. An inability to communicate in the normal manner meant no massing of forces on a single convoy target.
* Submarines from that era of the Great War [WW1] thought to strictly a defensive weapon and not intended for long-range offensive action. MOST sinking attributed to submarines as the result of deck gun fire and NOT torpedo attack.
* The German unrestricted submarine warfare of the WW1 period never having enough long-range boats to accomplish the task, German calculations regarding British resilience also grossly unfounded.