[sukhoi-30mki]

Image: Wikimedia Commons/Hunini/CC by-sa 3.0

[GraceG]

A sub powered by a closed loop Thorium Salt reactor with the ability to on site process it’s nuclear fule could theoretically stay submerged for DECADES!

Especially if you loaded it up with enough thorium fuel...

[PGR88]

Wartime prime minister General Hideki Tōjō catalogued submarine warfare among three critical determinants of Japan's defeat—high praise from someone in a position to know.

The entire US Pacific submarine service in WWII had less than 16,000 total members. Talk about punching above one's weight and over-sized contribution!

[ArmstedFragg]

With the munitions problems we had at the outset of WWII, mostly what we missed was the opportunity to discomfit Japanese troop transports with the loud clanging sounds we made bouncing torpedoes off them, and the unnecessary evasive maneuvers they had to make avoiding torpedoes that were going to pass underneath them.

[The_Media_never_lie]

Just, wow!

[xrmusn]

Funny...
Today I was thinking of how the ‘geniuses’ were pounding their chests about the ‘electric’ car that had a diesel engine.
They were so proud of themselves that they had ‘invented’ something.

Of course, I was wondering how often you would have to ‘go on a mountain’ unless of course you had a snorkel. But would still have to stop and recharge the batteries.

[MasterGunner01]

Observations on U.S. submarines in WW2.
1. Outside of teaching submariners the basics, most but not all American subs went to the Pacific.
2. Torpedoes in the submarine service, Mk 14, and surface fleet, Mk 15, were equally bad. The multiple deficiencies of faulty magnetic exploders, faulty depth keeping mechanism, and faulty contact exploders weren't solved until mid-1943. Then the Japanese really stated to lose ships.
3. Of the total numbers of merchant vessels and warships afloat on 7 December 1941, at the time of surrender on 2 September 1945, Japan had lost 1/3 of its warships and 2/3 of its merchant marine.
4. Most of the pre-war O, R, and S-class boats were used for training. The pre-war built boats — a few S-class, Barracuda-class, Argonaut and Narwhal-class, Dolphin and Cachalot-classes, P-class, Salmon-Sargo class, Tambor-Gar class, Gato-class, Balao-class, and Tench-class — were boats that bore most of the Pacific fighting.
5. A total of 52 submarines were lost, with 374 officers and 3,131 enlisted men. These personnel losses represented 16% of the officer and 13% of the enlisted operational personnel. Of the 52 losses, two submarines, Dorado and R-12, were lost in the Atlantic, S-26 was sunk in a collision off Panama and S-28 was an operational loss in training at Pearl Harbor. The remaining 48 were lost either directly or indirectly as a result of enemy action, or due to stranding on reefs during combat operations.S-39, S-36, S-27 and Darter were lost as a result of such strandings. In all of these events, all personnel were rescued.
6. U.S. World War II Submarine Operational Summary:
•Maximum number of U. S. Submarines in the Fleet = 288
•Number that made war patrols = 263
•Number of War Patrols made by Submarines in the Pacific = 1,474
•Number of days at sea by those Submarines = 70,838
•Number of Japanese ships attacked by submarines = 4,112
•Total number of Japanese ships sunk by submarines = 1,392
•Average number of merchant ships sunk/war patrol = 0.80
•Average number of naval vessels sunk/war patrol = 0.145
•Average number of all types of ships sunk/war patrol = 0.945
•Number of airmen rescued by Submarines = 504 by 86 Submarines
•Number of Submarines lost on war patrol = 41, or 1 out of every 6.41 submarines = 15.59%
•Number lost due all causes = 52 out of the 288 in the Fleet, or 1 out of every 5.54 Submarines = 18.06%
•Number of U.S. Submarine Commanding Officers = 465
•Duration of the war = 1,347 days

[MasterGunner01]

The latest diesel-electric, air independent propulsion subs are very hard to find and kill. One of the very best designs is the German U-212A design. The German Type 212A-class, also Italian Todaro-class, is a highly advanced design of non-nuclear submarine developed by Howaldtswerke-Deutsche Werft AG (HDW) for the German and Italian Navy. It features diesel propulsion and an additional air-independent propulsion (AIP) system using Siemens polymer electrolyte membrane (PEM) hydrogen fuel cells. The submarine can operate at high speed on diesel power or switch to the AIP system for silent slow cruising, staying submerged for up to three weeks without surfacing and with no exhaust heat. The system is also said to be vibration-free, extremely quiet and virtually undetectable.

Type 212A is the first of the only two fuel cell propulsion system equipped submarines ready for series production in 2007, the other being the Project 677 Lada-class submarine designed by the Russian's Rubin Design Bureau.