From what I gather/have read, the earliest boats to get the TDCs we see and use in the game (TDC Mk III) was first installed in the USS Tambor and all later subs till the MKIV came out which was adapted for the new torpedoes and the use of SJ radar. In the book i'm reading "Take Her Deep" Galantin described the USS Sculpin, a Sargo class sub as having an older, bulky, table top TDC in her control room.
Very brave of you to not use the TDC and input all of it by hand. Huzzah for Trigonometry!
