The Shark, 1971

[aheadflank]

That scenario isn't complex or doesn't have any outstanding features as well. However, I've played it lots of times and really enjoy it. On my opinion that's a good piece for therapy or to warm-up. Just try to control your units manually. Actually, you don't have much enough options – the waters are shallow, so the sub has no place to hide. This makes you get maximum from your maneuvering ability.
Making long things shorter, here are some tips I've revealed while playing this scenario. Hope, they will be interesting for newbies.

The first thing, what helos do, when proceeding ASW operation, is flying across the search area and deploying sonar in some sophisticated order (it may seem to be chaotic) to get the first contact (helos don't have sonobuyos in their loadout) Just don't allow them to do that. Subs detect active sonar from far distance, when helo can't yet detect a sub. The effective sonar's detection distance is only 3 nm. The key thing for sub capt. is to control the distance to any deployed sonar and keep the appropriate range, a bit higher, that may uncover you. You can use zones, that were just checked and are considered to be clear.

Your torpedoes may seem to be fast'n'deadly, but they never move directly along the line. Acoustic homing system causes some oscillations, that increase the route. They are really easy to run away from. Try to approach as close, as possible before you launch'em.

Whether your sub is detected by a ship and is found too close, AI is used to turning off the sonar and fleeing. Try to avoid detection until the very last moment, or you risk to use all the battery charge hunting the frigates. Closing down on periscope depth and visual monitoring brought me to success with higher chance, than turning on the sub's sonar to specify the ship's coordinates.