Apparently the doc on night surface tactics was in the original upload in September, , then I had to upload again due to couple file issues and did not realize the tactics file was not in the second upload. I am in process of editing/updating it as have learned some things since I wrote it in September, will post later today.
I don't get how you are being detected, esp at that range. I just tested a new patrol objective earlier, ran into large convoy* four columns five ships each with 7 escorts) October 1944. Slipped inside screen to center columns, sunk two tankers, crippled large merchant, which later went down, came under fire but didnt get hit, evaded. Chased through center of convoy by escort but outran him. Radar equipped DE closed in on me me, fired from guns at me from 4000 yards, I fired a MK 14 "down the throat" from stern tubes, when he saw the wakes, he turned to evade, bought me time to escape, he lost visual and radar contact, I disappeared into the night.
Even with enemy radar, can pull surface attacks off. Hopefully tactics write up will help you.