Hunting methods:
- first thing - using Type IX - mostly for more torpedoes, 10,5 cm deckgun and its flak.
More torpedoes = higher tonnage each patrol
1) raiding harbors / naval bases
- risky, but really good tonnage for this job
2) patrolling in high naval traffic areas and on convoy routes:
https://archive.org/details/SILENT_HUNTER_III_MAP
- using hydrophones a lot (regular checks when traveling or waiting in periscope depth & listening).
Hydrophone detection range > watch crew visual detection range.
3) checking map contacts
4) ambushing task forces with large warships
- they are fast so you need to have good position in right time