Torpedo boats, next to CVs, are the class that requires the most situational awareness and proper positioning to play well. To play them successfully, awareness of the routes that ships ordinarily take, and knowledge of typical behavior are essential. Most of these skills are learned from practice and not from instruction, but there are some general rules to torpedo boat play.
Firing torpedoes correctly is quite complicated, and requires a good amount of skill and map awareness. Usually when firing torpedoes, watching the target beforehand is essential, since it will show you how they will behave. Ships that maneuver often and erratically are probably aware of your presence, and should usually be your last targets. The perfect target is one that is not taking fire, has no reason to take a new course, and is moving to a new position. Usually torps are fired at ships that are running broadside to the launch position, but when firing at battleships, it is acceptable to launch torps regardless of their angle. “Flanking” is a typical strategy for torpedo boats, where the ship goes around a map edge, (usually alone) and tries to get shots onto the broadside of the enemy ships. This is both unnecessary, and harmful to the team, for a couple of reasons. Firstly, getting a good spread onto a target can be successfully done from many positions, such as the area in between caps, or even from the direction of your team. Secondly, this strategy often puts the DD in a risky position, and doesn’t allow the DD to scout or support the caps.
CVs are the mortal enemy of torpedo ships, and to play successfully in a match with a CV, torpedo boats must play very carefully. When positioning yourself in the game, always keep in mind the danger of the enemy CV spotting you, so position yourself close to the fleet, where you can run back to your team in case of spotting. Watch the minimap closely, look for opportunities to fire torpedoes while the enemy CV’s planes go elsewhere. Remember, CV planes must be right on top of your torpedoes to spot them, so there are often more opportunities than you think. Lastly, do not hunt the CV, it’s a waste of time, since he will permanently spot you and your torpedoes, and possibly outright sink you for attempting that.
Usually, torpedo boats will either avoid caps for the early game, or attempt to cap at the very edge of the cap. Capping is usually only done once it is obvious that there are no enemy DDs around to contest you. Once the area is captured (or you have been forced out by an enemy DD), stay moderately close to your team and launch torpedoes at the enemy ships, depending on their course and viability as targets. This comprises most of the gameplay, try to capture what you can, and avoid enemy DDs unless you have significant support.
1) Unless you are confident that ships will be where you are firing torpedoes, do not fire blind spreads of torpedoes, it’s usually a waste of time. Instead, wait for a ship to be detected and has picked a course, then launch torpedoes. Usually, unless two or three ships are in a smoke screen, firing at a smoke screen is a waste of time .
2) Secondly, only use your guns from smoke or while concealed from behind an island. Firing from the open will give away your position, alerting the enemy to the direction from which torpedoes would be launched. (This can sometimes be used to your advantage, since they’ll turn once they see you, they can be baited into turning into a torpedo spread.)
3) Stay quite a bit further away from the enemy team, you can’t directly fight the enemy DDs, so be wary until you know where they are. When they are spotted, stay away from them, but try to stay close enough to the enemy team to be able to reliably land torpedoes.
4) When it’s necessary, use your guns to engage very low health targets, you can usually kill them faster with guns then you would with torpedoes.
5) Try to fire torpedoes into groups of ships that are moving along the same course, this makes it easier to land hits.
6) Stay away from radar cruisers., If you are in range of one, try to torpedo it, then get behind cover before they pop their radar. Most ships have radar that ranges from 11-9 kilometers, although there are exceptions to these. Also, high tier German ships have a long ranged hydro acoustic, which can reach up to 5.8km. Usually it is pointless to shoot at German ships once they have been alerted to your presence.
Torpedo boats should use a build that maximizes their strength, usually the preferred captain skills are concealment expert, torpedo reload, concealment, and radio location (This gives a good idea where the enemy DDs are).
For modules, the tier 8 concealment module, and the tier IX torpedo reload module are essential, the rest are usually up to personal preference.
Good luck and fair seas captains, I hope that this helps.