Hi all!
I would really like to enjoy the game but there's something i need to know to do it.
My main problem is detection by destroyers or any other ships. What i want to know is:
1.What is safe range(there's only 10-20% of chance to be spoted) when i look through periscope(of course im submerged

(i had once looked through periscope while being on surface

))?
2.What is range of japan destroyer's sonar or something? How does it works? How can i avoid it or how i have to behave while being in range?
3.What's that ping-ping sound? I think it's ASDIC, but i need answers as above.
Thanks for help and sry for my english.