Single Mission Tokyo Harbor Cruise... Just...HOW?!
 

How on earth do you beat this mission? The mouth of the harbor is so shallow that it has a depth of 13m... in order the pass, the conn tower needs to stick out of the water for a pretty long time. How do you do that without being spotted by the destroyer?
Edit: this is with RA 1.44

This mission is KSM04.ms. You can rename to KSM04.mu and edit it in Mission Editor.

I have to agree with you that entrance to the Tokyo Bay is way shallower than 18 m which is PD for Kilo. So that is problem #1. A bigger problem I think is that the frigate detects your presence right after the start of the mission and this is when all quickly is over with.

Moving frigate to the north of the bay or altering its doctrine are my only suggestions here.

Scenario Map with contour line 18 m deep marked by crosses.
https://image.ibb.co/j5dt77/dump01289228.jpg