First contact with a sub is the most dangerous time. The sub is probably at close range. It will fire a large spread of torpedoes, which is the hardest to evade. Your ships are moving slowly and may be on an unfavourable heading. Later on in the engagement the sub will usually be firing zero or one torpedo per turn, at longer range, with most of your ships moving away evasively at high speed. But at first contact your initial action is:

• Locate the sub (or subs). This is most important. Sometimes during the first turn you do not have a sonar bearing for some ships. It's important to watch the sight picture from the sub's perspective from its torpedo run. Compare that to your map to figure out the direction to the sub. Once you have a sonar bearing, figure out where the sub is on the map and relative to your ships, so that you can steer your ships first away from the torpedoes and then away from the sub(s). If there is more than one sub it may take you a few turns to spot all of them.
  
• All ships near the subs that might be fired upon (within 8000 yards) accelerate to flank speed and make the hardest possible turn away from the direction of the sub. Keep turning away in the same direction until the initial torpedo salvo has gone past. For ships that cannot turn very hard, or are very close to the sub, also consider braking hard, if they were already travelling in a direction away from the bearing of the sub. Ideally you want every ship moving 90 degrees away from the bearing of the sub when it fired. So if the sub was directly south of you, you want to get everyone moving east or west.
  
• If you have land-based aircraft available consider making immediate air attacks on the closest submarines - even if only bombs or rockets are available rather than depth charges.
  
• After the first evasive maneuver, get all non-destroyer ships to flank speed and move them directly away from the sub or subs. Move by zigzagging left, right. If you have warships moving away with merchants, make smoke, this will inhibit attacks (but not totally prevent it). It is also not a bad idea to spread out - certainly don't get bunched up. On the other hand, if you are making smoke, get merchants under the cover of the smoke even if it bunches them up a bit.
  
• move each ship individually. before you move it, scan the water surface and (ok, cheating) under the water for torpedo tracks. If you see torpedo tracks you can make a more accurate evasive maneuver, sometimes even turning between the tracks of a salvo.
  
• If you have carriers, once they're out of immediate danger, ready aircraft, preferably torpedo bombers. Torpedo bombers are deadly against submarines at the depths (surfaced and Periscope Depth) at which subs are a threat. If you have more valuable capital ships to protect it may even be worth putting an escort carrier at risk to get 4 torpedo bombers airborne. But any aircraft, even fighters with bombs, are useful against subs.

It is now time to counter-attack with your ships.

• After the first evasive maneuver, destroyers should now converge on the subs. If there are multiple subs and multiple destroyers, concentrate and kill one sub at a time, starting with the nearest. All surface vessels can outrun subs so the situation is now getting better rather than worse; time is on your side (unless there is a sub pack right in the middle of your convoy).
  
• If you approach with your destroyers making smoke, the subs will usually not attack. This is not very realistic but it's a deliberate game mechanic. If you think it's cheating or unrealistic, don't use it.
  
• If you approach without smoke you need to watch for torpedoes. Every time torpedoes are fired make a hard course change. Usually you want to keep to the outside of the sub rather than moving further into its torpedo arc. Usually you will only have to dodge a single torpedo that has been reloaded, which is easier. If you are very close you might want to brake (go to Back speed) as well. Remember to reapply flank speed on the next turn.
  
• Aim for slightly behind the sub. Circle towards its flank and rear: initially keep the sub at 90 or 270 degrees bearing and keep your range about 5000 yards (the range a sub torpedo travels in one turn). Move outside the subs torpedo arcs which are 45 degrees either side of its bow and stern (the opposite of a destroyer's torpedo arcs). When you move around to just outside the torpedo arc, start to move in. Bring the sub onto heading 45 (if it is to your right) or 315 (if it is to your left). As you get closer come on to 30 or 330. Watch the map to see how much closer you get each turn.
  
• Don't spend too long outside 5000 yards because this increases the chance that the sub will be able to Disengage / Leave Combat.
  
• It is much easier if you attack with two destroyers, one coming left and one coming right. However if you only have one destroyer, you can still destroy the sub reliably with one.
  
• You can cheat by checking the heading of the sub in the 3D view. Select the sub (even if it's just a sonar target and even if it's obscured by smoke). Then pan the camera down below the water and you will see the sub. Yes this is cheating. However sonar was useful for getting speed and heading information for subs (particularly for pairs of destroyers) so it's not entirely unhistorical.
  
• Be very careful as you pass under 2500 - 3000 yards. You cannot dodge a torpedo shot under 2500 yards. It hits you instantly. Make sure you are well outside the front and rear torpedo arcs and the sub could not turn to bring you into arc. Subs are actually quite maneuverable, they turn about as fast as a light cruiser though not as fast as a destroyer (luckily!). The most dangerous zone is between 2500 and 1000 yards.
  
• Remember that rangefinder estimates are only estimates. Don't rely on them to be perfect - much too risky. Check the map, it is more accurate.
  
  Your goal is to get into the safe zone, under 1000 yards, at which distance torpedoes do not arm. You need to get into this safe zone without being torpedoed by the sub. Then you need to stay within the safe zone until you kill the sub.
  
  ( If you want to be able to turn into, or even between, torpedo tracks, you need to practice handling your ship a lot. For this kind of evasive maneuver it is very important to understand what the curved path of each ship type looks like when it is turning hard at different speeds - flank speed, normal top speed, damaged speeds. Practice this in "practice" games so you know it. If nothing else, learn how your destroyers turn at fully developed flank speed. Not just 30 degree rudder but all levels of rudder. You need to know the difference between a 25 degree rudder turn and a 20 degree rudder turn, and between a 30 degree rudder turn at 25 knots and a 30 degree rudder turn at 33 knots. If you know your ship's handling intimately you can turn into a torpedo salvo and slip right through it. ) See my other Guide, Turn Rates Of Vessels.
  

• Once you get under 1000 yards you are home free and the sub is dead unless it "Leaves Combat" (which is really annoying and probably a bug). Under 1000 yards torpedoes will not arm, so the sub is toothless. At this point SLOW DOWN to avoid overrunning out of the 1000 yard safe zone. You want to drive over the green spot and dump depth charges to the rear.
  
• Yes you could kill a sub with torpedos but it is a waste, particularly in Battle of the Atlantic when you have to go home to resupply, or even in a Campaign game if there are other surface vessels to fight. Depth charges are "free" and infinite.
  
• But - don't drop depth charges unless you have a good chance of a kill. Every use of depth charges gives the sub a chance to break sonar contact and escape. Drop depth charges when the green circle is more or less at 180 degrees bearing (+/- 10-15 degrees maybe). Before you drop depth charges, select the sub, pan underwater and lock the view on the sub so you can see what's happening. If you fail to kill it you will get a better idea how to position next time.
  
• Once you get over the sub it will start to dive. Be aware that the range indication to the sub includes the depth (and is still probably wrong). For example a sub directly beneath you at Shallow depth might show a "distance" of 500 yards. (This is wrong because Shallow depth is more like 100 feet). The green circle on the surface of the water reliably shows the (2D) position of the sub. Ignore the rangefinder, but be sure to stay in the 1000 yards safe radius (using the map or by eye).
  
• Once the sub is very close it can be hard to maneuver your bow over the green circle so that you cut the green circle and pass over it. It is often easier to try to point your stern at the green circle. Point your stern like it's a big short-range gun. Then you will depth charge the sub.
  
• Work quickly and efficiently because if you wait long enough the sub will escape. But you can kill the sub even at Very Deep depth with accurate depth charge attacks.
  
• If you have two destroyers, beware of collisions and getting in each other's way. Remember there is no friendly fire (which with depth charges is less unrealistic) so you can overlap your attacks.
  
• If you have Hedgehog/Squid (Allied ships later in the war) you can do a forward-firing attack as you first arrive at the sub's location. Once you are actually on station you want to switch to depth charges but it's useful as the first attack. As you are approaching the sub, each turn just switch to Hedgehog so you can see the target circle. Each turn gauge how much closer the circle has got to the green circle of the sub, so you can adjust speed and angle to that the Hedgehog target circle eventually arrives over the green circle of the sub.
  

It is possible to fight submarines with cruisers (preferably light cruisers), though you would not want to do so unless you did not have much choice.

The tactics are similar to destroyer tactics, except your cruisers are less maneuverable and they are bigger targets. Expect to take some hits. Luckily you can usually absorb maybe one or two torpedo hits. Also your cruisers do not have depth charges, so you can only attack with torpedoes (and you can do nothing if the subs dive below periscope depth).

The tactic then is similar to destroyers:

• Evade the first big spread salvos
  
• Identify the sub locations (hopefully you have at least one destroyer with you?)
  
• Get out of lethal range - above 5000 yards, preferably above 8000
  
• Circle back on the sub, moving outside of his forward torpedo arc
  
• Once you are out of his arc, cut in more sharply toward his rear. Make sure you are in his side arc while you close between 5000 - 2500 - 1000 yards.
  
• At 2500 yards, still in his side arc (out of forward torpedo arc), turn so the sub is in your own torpedo arc, and kill the sub. At 2500 yards you cannot miss and the sub cannot evade. Be very careful of the range (check the map, don't trust the rangefinder).
  
• You can try a shot at 4000 yards, as your torpedo can cover that in one turn, but the sub will get a move before the torpedo hits, so look at the map, look at the sub's speed and turn radius, and estimate where he will be. You may need a salvo of 2 or even 3 torpedos at this range.

All of this is much the same as you would do with a destroyer if you did not want to use depth charges. The main difference is that with a cruiser you are more cautious, stay further away, circle round more carefully, don't take chances like you can in a destroyer.

Locating the sub is crucial so if you have only one destroyer, it's almost worth protecting the destroyer and its sonar and letting the cruisers(s) do the fighting. The cruisers only get a "submerged sub" contact (from their scout aircraft), with no range or bearing information.

(I have had one lone light cruiser with only one escorting destroyer get ambushed by FIVE U-30 series subs, surrounded on all sides at torpedo range, and not only did they both survive, the cruiser killed 4 of the 5 subs with torpedo shots. The 5th sub Disengaged. The destroyer never even made it into depth charge range the whole time, it was too busy dancing its way out of the torpedo arcs and trying to get into attack position. As the destroyer was finally closing on the last sub, the cruiser finished it off with a perfect long range "cross the T" torpedo shot!)

Another tactic you can do with cruisers (or destroyers if you want to use up torpedoes) is the long range "cross the T" shot. You will often see subs moving in straight lines. It means they have not detected you (I think). It's possible to hit these subs head on at very long ranges that are normally impossible. What you have to do is get across the path of the sub at right angles. Aim your torpedo back along the path of the sub. If you look on the map, you should see your torpedo bearing running exactly along the sub's "snail trail" of dots on the map.

(Actually maybe this should be called the "Cross the T and dot the I's" shot!)

If you get it lined up on the sub's trail like that, you will most likely get a hit, even though it is a head-on attack (which is the hardest angle to succeed with, usually).

I do not usually recommend gunnery against subs, even though it is recommended in the game manual. My reason is that gunnery against subs tends to reduce the number of sub kills (like excessive depth charging), so if you priority is to kill subs, don't use gunfire.

Typically what happens when you use gunfire is that it has no effect for a while, until you actually hit a sub (you hear the different explosion sound, less 'watery'). This causes the sub Light damage, at which point it generally leaves combat. There goes your chance to kill the sub (and possibly a waste of lots of hard work or even damaged or lost ships).

So my suggestion is not to use gunfire against subs unless you really don't care about killing the subs. If you just want to drive them away, that's fine. Situations when you might use gunfire:

• The range is under 5000 yards (so in theory they can't flee - but in practice, they still do) and you need the sub to dive because you are worried it may torpedo you. (But then the odds of making it dive exactly when you need it to, are pretty slim odds).
  
• You are protecting merchants or capital ships and protecting them is more important than taking out the subs
  
• You are outnumbered or ambushed, the tactical situation is very bad, and you need to even the odds by getting some of the subs to quit (or at least dive), at least until the odds or the tactical situation has improved in your favour somewhat
  
• You don't enjoy prosecuting submarine contacts, it's not fun for you, so you just want to get rid of them as fast as possible.

"I have nothing else to do with my turn" is not a good reason to use gunfire on subs. You are just wasting the Renown and Experience you could get from killing the sub, for no good reason.

To avoid your capital ships being sunk: maneuvering is key. The AI fires four torpedoes, spaced out. Before you move, look at the angle of the incoming torpedoes relative to your ship (In submariner terms, this is the 'Angle on Bow'.) Decide whether or not you should turn in to the torpedoes or away from them (As a general rule...if the torpedoes are coming in from the aft portion of the ship, turn away. In they're coming from the bow portion, turn in.) Next, find the space between torpedoes you can best take advantage of and try to fit the ship between there.

With luck, the torpedoes will miss and you can force the sub under and destroy it.

Destroyer escorts are a great help (essential), provided your capital ships survive the initial attack. But the destroyers are not much help in that in initial attack. In fact they may even hinder it because the more ships you have in a scenario, the more tightly packed they are on turn 1. In turns 1 and 2, destroyers can help only in one of two unrealistic ways. 1, by diving in front of the torp spread and deliberately sacrificing themselves. 2. if they can manage to kill all the subs with torpedoes so that the scenario ends before the 'torpedoes in the water' hit the capital ships.

Additional material by TigerAce121

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