If you are just starting go with km as you do not need incredibly high engineers to go fast..

IJN subs are good with high level crews as you get nice reload and speed

KM is great for SS vs SS because of the proxy torps and agileness but that does not mean you can not engage
battleships...of all the nations km is the most likely to kill the enemy battleships as you have a greater chance
of getting through the other subs and destroyers while still having the speed to reach the enemy capital
ships...just because you have 4 torpedoes as opposed to 8 does not mean that you don't have the power to
kill a bb...all subs have powerful enough torpedoes to destroy a bb6 if given the chance (maybe not uk lol)

Ijn subs can be decent in SS vs SS...all you have to do is spray those 8 tubes like a shotgun across the map
and you will probably catch an enemy before he sees you... but you have to be lucky and km is still better

Just like cv's trying to get bombers through the fighter nets a subs main goal is to break through to the enemy
bb's and the subs that can do that will win the day...funny thing is...historically in WWII SS vs SS combat was
pretty much nonexistent cause the subs couldn't see eachother and aim effectively

all ss are useble
but if u have anny think but km u do not do ss vs ss
go for the bb/cv and use the torps careful and shoot accurate
if u see a km ss run for the hills

Not only ijn ss4, all the ijn ss is useless against ss vs ss.

i send gradual 4 torps and all of them have passed under the ship. Whats so
special with distance torping? They can easly alert,manuever and run away from
torps.
Turning force is unbelievable. you are wasting your 1/4 of your oxigen while turning
to target.

I wish i had started Km Ss.

IJN ss4 is the worst in a sub vs sub war(turns like a truck!).
Also is the best by FAR vs CA/BB/CV
KM ss4 is a well balanced sub against every target (all around sub).

Yah i agree that IJN Torps are so awesome! but Jap subs are too soft it needs a higher SD.

best sub

for ss vs ss is km
for ss vs smal ships aka ff/dd and some cl is km
for all cl/ca/cv/and bb ijn and mn ss are good
ijn ss is a bb killer mn have the hardest hitting torps
i prefur the mn over the ijn becos it has 6 fronts and 2 rear torps
vs the 8 front and no rear on the ijn and the frence 4 is a realy smal boat
in mn u have a smal chance of killing that pesky dd that
trys to dc u from the back in ijn u don't

as for uk it is useble at high lvl
us and sn are bad

like everyone said, i say km is best in sub vs sub and for sneak attack and against fast
and small ship due to its famous proxy torps, and 2nd best is ijn, it really give a hard
punch but you need to be a good aimer.

"In NF, no. Only 3 support slots, few torp tubes, good torps yes, but it isn't that good
with few torps slots.
And the SS4 deck gun isn't al that good, SS are for torping, not gunning. "

thats why its built that way in nf, imagine a km ss4 with 4 slots (2 high level engies) =
long oh, few torp slots is enough, km reload on ss is fast as i see (it would be
overpowered if they put 8 torp slot + proxy torp + fast reload speed),
the u flak is suppose to be the only aa sub but player find some creativity in sinking
ship with its pompom km style :D

UK is good for me in dodging,speed, and repair,. BUT!!! the torp damage is a big JOKE!!..
So it means UK SS are only for Scouting not For Hunting/Killing,. Lol

Everyone says KM, in real life WW2, they were the best subs.
In NF, no. Only 3 support slots, few torp tubes, good torps yes, but it isn't that good
with few torps slots.
And the SS4 deck gun isn't al that good, SS are for torping, not gunning.

Ultra_dog totally hit the mark. Now all we need is Lj, devildog, or some other TNF
wannabe to come in and tell us why it should be that way. :(