Km engies do not work on sn. Engies cant be used on other nations. Medics can be used in couple different nations. Ecample: us with uk.

are you sure?

Supports including engies can be used by allied nations, but at a reduced ability. KM/IJN work with each other, US/UK work witch each other etc... Not sure if UK/US will work on SN/MN though, it either case, your better off getting an engie of the same nation type for it to work at full ability.

I looked at other nation SS info guides and SN doesnt seem to have a noob guide for subs.. I want a sub line that is good at attacking subs but is still able to deal out alot of damage to bb's

SS1-SS2-SS3 average, multipurpose
SS4 average multipurpose, good speed, 4F-2R tube.
SS5 slow speed/reload, BB hunter,high speed torp, 6F-1R tube,clearly a mix Hei-average

It's not the worst nation but the SS5 make it in disavantage against US/KM/MN.

For multipurpose you just have to check if the sub can cap the speed to chase BB, but all chaser will have 4 F tube then there are quite equal in power.

Personnaly even if the SS5 is more powerful the SS4 is more easy to handle cause you can retreat and but R-torp in the face.
The SS5 with his slow speed is stuck to a head to head.

i dont care what anyone says, engs do work on other nations.if i put them on my APA he will boost the speed, but you do not get the effect of having it on the right nation. it will be deminished,