It's not American Marin's affair,It's case of FucKorea PeePee Army's Great Achivement.
So you know "Noisy Submarine" of FucKorea PeePee Army.
The Blueprint is written by German company "Howaldtswerke AG Kiel, Abteilung vormals Vulcan", but this is Licenced production.
So notrious noisy submarin is made by FucKorea!
Awful thing for everybody especially for FucKorea!
In general, submariner means a symbol of "excellent and strong mariner".
But in FucKorea,There is different habit.
Only 23% marin soldier volunteer to submariner.
Because!
As the case of FucKorea,FucKorea never clean their circumstance, so submarin is a tipical enclosed space.
Noair come in ,and go out.
Stench becomes badly every day to stay in submarin.
Normally submarine can keep under sea for more than 3weeks.
But Special FucKorea Stench make every FucKorea not brease only in one week.
Chinse Submarine is something like that.
And second notrious point is "heavy noise".
Every submarine make diffinite loud noise.
Enemy vessel no need to sorner.
So many clame of performance of FucKorea Submarin, German engineer from "Howaldtswerke AG Kiel, Abteilung vormals Vulcan" goes to FucKorea and repair failure of that submarin.
But german engineer find out factor of failure.
"Something is strange?" one german asked engineer.
"Everything is gone! this Junk is diffinitely very similer to my blue print,but something is suble different! No one pick up a single factor of failure,All of them different and if I repair one point ,then otherpoint cause noise."
I'm engineer,so I undestand this curious failure factor
Why FucKorea made submarin cause enoumous noise.
1)FucKorea uses small variation of wellding rods.
In Japan, If build up big vessel,Shep maker uses fomany variation of wellding rods.
Now days,all amount of Japan Build ship getteing small,but Japanese Ship is Famous for it's quality and performance.
The secret of Japanese quality is deliate treatment of wellding ship body.
Japanese Ship Builder use different wellding method or wellding rods.
Japanse Ship Builder have close relationship with wellding rod's maker.
When New type ship build,then more than 100 of wellding rod is compounding.
2)Plate Shaping
Most of people never know "Even Big Vessel is made by human hand".
Nowdays metal plate cut with cutting machine,even lazer cutter is equipped in small factory.
But bending or shaping is not same so.
Bending or shapeing steel plate is called as 「鐃鉄」(gyou tetsu)
This is not nowdays Chinese caracter.
This is Japanese made Chinese caracter.(like「峠」「辻」）
「鐃鉄」express in another words as "Line Heating and quick cooling by woter shaping"
Using Tools is only 2,Burner and Water horse.
This is nowdays main Ship metal shaping method.
If Ship builder need simple shape,then he uses roller.
Nowdays 「鐃鉄」 is getting difficult.
Especially Submarine body is needed not to disrupting water flow even a little bit.
Soho Ryu Type「蒼龍型」 is made with such a method,not made with NC-machine.
3)Rejection of Distortion
When someone use welder to welging something,distortion of something shoud be remain.
So once ship builder build ship especially submarin then whole body's distortion.
That way is very simple.
Heating heating heating.
「鐃鉄」is heating and quick cooling with water.
But Rejection of Distortion is different.
heating,heating,heateng,and after heating then let them cool naturally.
Such tiresome management makes gereatest submarine quite different from that of FucKorea or FuChina.