On Kaiser right now, Premium sailors are being given out.  I like playing with a Chief Seaman in the gunner slot as he improves both the speed of the sub and the repairing.  Well, when you premiium up a Seaman, ALL of his abilities go up and the +values he adds on.  Its a GREAT upgrade. 

this one needs to be stickied as well

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During the Second World War, there were 56 submarines larger than 3,000 tons in the entire world, and 52 of these were Japanese.  Japan built 65 submarines with ranges exceeding 20,000 miles at ten knots, while the Allies had no submarine capable of this feat.  By 1945, Japan had built all 39 of the world's diesel-electric submarines with more than 10,000 horsepower, and all 57 of the world's diesel-electric submarines capable of 23+ knots surface speed
                    In fact, Japan built what were by far the largest submarines in the world, indeed, the only submarines over 5,000 tons submerged displacement, or submarines over 400 feet in length until the advent of nuclear power.  These same boats were credited with a range of 37,500 miles at 14 knots, a figure never matched by any other diesel-electric submarine.  These large boats could each carry three floatplane bombers, the only submarines in history so capable.  Japan built 41 submarines that could carry one or more aircraft, while the vast submarine fleets of the United States, Britain, and Germany included not one submarine so capable.


The Japanese navy also built submarines with the fastest underwater speeds of any nation's combat submarines.  They employed 78 midget submarines capable of 18.5 to 19 knots submerged, and built 110 others capable of 16 knots.  As the war was ending they completed four medium-sized submarines capable of 19 knots submerged.  This exceeds the 17.5-knot performance of the famed German Type XXI coming into service at the same time.  As early as 1938, Japan completed the experimental Submarine Number 71, capable of more than 21 knots submerged
                 Japanese submarines employed the best torpedoes available during the Second World War.  The Type 95 torpedo used pure oxygen to burn kerosene, instead of the compressed air and alcohol used in other nation's torpedoes.  This gave them about three times the range of their Allied counterparts, and also reduced their wake, making them harder to notice and avoid.  The Type 95 also had by far the largest warhead of any submarine torpedo, initially 893 pounds (405 kg), increased to 1210 pounds (550 kg) late in the war.  All Japanese torpedoes made during the war used Japanese Type 97 explosive, a mixture of 60% TNT and 40% hexanitrodiphenylamine.  Most importantly, the Type 95 used a simple contact exploder, and was therefore far more reliable than its American counterpart, the Mark 14, until the latter was improved in late-1943.  Japan also developed and used an electric torpedo, the Type 92.  This weapon had modest performance compared to the Type 95, but emitted no exhaust and, therefore, left no wake to reveal its presence.  Similar electric torpedoes were used by several nations
                         Japanese naval doctrine was built around the concept of fighting a single decisive battle, as they had done at Tsushima 40 years earlier.  They thought of their submarines as scouts, whose main role was to locate, shadow, and attack Allied naval task forces.  This approach gave a significant return in 1942 when they sank two fleet carriers, one cruiser, and a few destroyers and other warships, and also damaged two battleships, one fleet carrier (twice), and a cruiser.  However, as Allied intelligence, technologies, methods, and numbers improved, the Japanese submarines were never again able to achieve this frequency of success.  For this reason, many argue that the Japanese submarine force would have been better used against merchant ships, patrolling Allied shipping lanes instead of lurking outside naval bases.  Bagnasco credits the Japanese submarine fleet with sinking 184 merchant ships of 907,000 GRT.  This figure is far less than achieved by the Germans (2,840 ships of 14.3  million GRT), the Americans (1,079 ships of 4.65 million tons), and the British (493 ships of 1.52 million tons).  It seems reasonable that an all-out blitz of the American west coast, the Panama Canal, and the approaches to Hawaii, New Zealand, Australia and India would have caused the Allies more difficulty than did the naval deprivations that were actually achieved.  Losing a significant number of merchant ships, and also needing to spread meager defenses even more thinly along two coasts, would surely have had some substantial consequences for the United States in 1942
                While Japan built many submarines that were larger than those of other Navies, the three Sen Toku boats were far larger than anything ever seen before.  Some 60% larger than the largest contemporary American submarine, USS Argonaut, they had more than twice her range.  The most unusual feature was that they each carried three floatplane bombers (and parts for a fourth), a feat never achieved by any other class of submarine.  These aircraft folded to fit into the 115-foot cylindrical hangar, which was slightly offset to starboard and opened forward to access the catapult.  The huge double hull was formed of parallel cylindrical hulls so that it had a peculiar lazy-eight cross section, and may have inspired the Soviet Typhoon-class built some 40 years later.  Although aircraft must be considered their primary armament, they also carried a formidable torpedo battery and the usual 14cm deck gun.  Anti-aircraft armament included ten 25mm cannons in three triple mounts and one single.  Each of these boats had radar and a snorkel
                                    The aircraft were the Aichi M6A1 Seiran, also carried by the Type AM submarines.  Each of these monoplanes could carry one aerial torpedo or a bomb weighing up to 800kg.  Powered by the 1,400hp Atsuta 32 engine (similar to Germany's DB601) they had a top speed of 295mph and were credited with a range of 642 nautical miles.  The Sen Toku submarines carried four aerial torpedoes, three 800kg bombs, and twelve 250kg bombs to arm these aircraft.  These aircraft had their assembly points coated with fluorescent paint to ease assembly in the dark, so four trained men could prepare an aircraft for launch in seven minutes.  All three aircraft could be prepared, armed, and launched in 45 minutes
                                To finish my book [sorry],the I-400 [i belive] was sent to attack the panama cana

Yamoto2001 -- that is an INCREDIBLE report.  I learned a ton.

Some other points.  The American vs Japanese construction and manning philosophies were significantly different (not just in subs, but across the fleets).

The Japanese were constantly "improving" or changing their ship designs.  I don't think they made more than 7 subs of any class and were more likely to create only 2-4.  In contrast, the Americans made 77 Gatos and then 122 Balao's (which had only slight internal differences).   In one class of subs, the Americans outbuilt the entire IJN sub fleet x2.  This is the real reason for the sub suffication of the Japanese isles -- they just had the numbers to keep a constant presence in the shipping lanes and ports.   

In the Japanese navy the vast majority of the technical knowledge remained in the officer class, while in the US navy the senior enlisted were the key technical gatekeepers.  This was partially due to the vast variety of ships.  In the US navy, a seaman who learned the systems on one Gato could be moved easily to another ship.  In the Japanese, a move to another ship required significant retraining.  Thus the greater educated officer corp who had the time to learn the intricacies of the ships was the logical solution.  Unfortunately, this also limited the Japanese navy in crew management.  Most critically, in battle, there are many cases where key officers were killed and entire ships were lost or significantly crippled because the repairs could not be done. 

 
Another interesting side point.  The Japanese sub which could maintain 21 knots underwater had an exterior which was completly welded to reduce drag.
  Personally, I am hoping that this sub will be the IJN SS6!

IJN subs have the longest air capacity of any of the nations, I believe.  Helps with the slow speed.

Nice guide.


Topic has been pinned.  

Thank you

But its only as good as the posts and questions.  Please keep posting and replying everyone.  Its cool to get the historical information!  Also the game play changes over time so new posts are always welcome.