In the game there are:

Torpedo Sub-Types:  (these are stored in the F1 annex Guidance field so 66 = 'B', 78 = 'x', etc.)

1. 'B' - Active/Passive seeker
2. '2' - Double-wire guided
3. None
4. 'P' - Passive Seeker
5. '1' - Single-wire guided
6. 'S' - Straight-running
7. Unknown
8. 'X', 'x' - Wake following, term active
9. 'A' - Active seeker (this one is not in the default PE for some reason)

Torpedo Codes: 

1. DE
2. Payload
3. Quiet

I remember "Unknow" is actually the active seeker.