ASW Weapons Employment

[Molon Labe]

Post your ASW Weapons Employment tactics here!
I'll go first (I feel like I'm playing Roschambo).

(See also the SCHQ/NCHQ TACMAN for weapons employment tactics)

Conventional torpedo attacks: This section is about attacking a contact that you have tracked, localized, and classified.

A normal ASW attack will involve the MK 48 ADCAP or the 65cm torpedo, both of which have 27nm ranges and are wireguided; the Mk48 has a 5 knot speed advantage. At the moment of firing, your main concerns should be the number of weapons to fire and the presets on the weapons. [Note: In DW 1.04+, torpedo range is variable with speed. Maximum range occurs 10 knots below max speed, and the range as max speed is 20% below maximum.]

In Sub Command, a single torpedo attack was a viable option. In DW, since decoys will destroy torpedoes, quantity unfortunately must take the place of accuracy. [Version update: DW 1.04 added a variable in DangerousWaters.ini that allows players to control if and how often torpedoes explode on decoys. This setting controls expendable decoys AND towed decoys equally.] 688I's and Akulas should fire at least two torpedoes (thus saving two for a second salvo or another target), while Seawolves should fire at least three. Assign these weapons to the target; do not use snapshots on a spread bearing...The goal is to eventually have the torpedoes attack the target from different directions AT THE SAME TIME. A spread will result in uneven staggering (once the target evades) and will decrease the likelihood of a hit.

The enable range should be set a few thousand yds/m short of the target's actual range. Keep in mind the accuracy of your solution, and the possibility that you might be killed before being able to resteer your torps or enable them manually. 75% of the range of the sub is a good rule of wrist in most cases.

The ceiling preset can help you to prevent hitting surface ships. In DW, the torpedo can explode if it passes under a ship; the torp must be more than 200ft deep to prevent this (if anyone has firmer data, please post). Unfortunately, pre-enabling and re-enabling the torpedo will sometimes cause it to "forget" its ceiling, and it may climb anyways. Don't depend on the ceiling to take the place of good TMA.

Just set the floor to maximum. The floor setting was used in SC to prevent the torps from hitting sunken ships under the max depth of the target. Since torps do not home in on wrecks in DW, there is no need to restrict the depth of the torp when attacking submarines except in special cases. (For example, if you have an allied SSN near a hostile Kilo; your SSN can dive to >300m and you can set the floor to 300m/984ft. The torpedo will (hopefully) not attack the allied sub below the floor).

Depth is a bit trickier. This is the depth the torp will go to once enabled (when pre-enabled, it will return to the depth it was launched at). Ideally, you should set the weapon at the slowest point on the SSP, where its sonar performance will be the best. If there is a strong layer, however, its a good idea to have some above it as well as below it. Also note the terrain, you will need to set a search depth above any terrain feautres so that the torpedo can see past them, and will not run into them.

Finally, after setting all your presets, move the ship to a depth higher than the seafloor in the vicinity of your target. Remember, if you pre-enable your weapon it will return to the depth it was launched at, make sure if that happens the torp doesn't hit the mud.

After launching, clear datum, but slow occasionally to track the target and to check for counterfire. Resteer your weapons based on your updates. Once your weapons close in, resteer them to a spread course. Have your weapons attack the target with as much angular separation as possible, this will make them more difficult to decoy.

Counterfire (snapshots): Sometimes you don't have the initiative, and have to respond to someone else's attack. Upon recieving a TIW alert, and determining that the torpedo is from a hostile submarine, you should fire a snapshot as soon as possible. Note the location of any neutrals and fire at least two weapons, either directly down the TIW bearing or on a spread angle of ~20 degrees. Spreading the torpedoes is more tactically feasible than it was before because you don't know the location or course of the enemy sub, right now its more important to find him.

If you think you are too far to get a sonar trace on your target, consider an evasion course that is partially toward your enemy. Getting a contact will help you resteer your weapons for an effective attack, instead of an attack that merely hinders the enemy sub from attacking you effectively. Also, track the enemy torpedo, the history of the torpedo will lead back to the location it was fired from, giving you a range to go with the TIW bearing. Take note of if your torps acquire anything when enabled...even if its a CM, the launching sub will be close...get all your torps searching in that area.

Kilo Torpedo Attacks: The two ASW torps are the TEST and USET torpedoes. Of these, the USET is superior, but is carried only by the Russian kilos. It has a 50 knot top speed--as good as the 65cm torp--but has only a 20km/10.8nm range and is not wire guided. The TEST has a slow 40kt top speed and the same range as the USET; it is also wire guided, but due to the ranges it is used at wire guidance does not help much.

The key to successful torpedo attack with either weapon is getting as close as possible to the target. The short range of both weapons means that your enemy will likely outrun the weapon. Fortunately, the Kilo is very quiet and will remain undetected by passive means to enemy submarines until the are closer than 5nm. Fire at least three weapons to deal with CMs, and immediately run (on a lag LOS) and drop CMs after firing--there will be snapshots soon.

[Molon Labe]

ASW Missile Attacks: There are three ASW missiles carried by the Akulas and Kilos: The SS-N-15 Starfish (Russian Kilos only), The SS-N-16 Stallion (Akulas only), and the SS-N-27 (Akulas and Chinese Kilo 368 (under the name 91RE1)). EDIT: The torpedoes dropped from these missiles will plunge about 100m/300ft into the water before leveling out--keep this in mind when choosing to use them.

The SS-N-27 is the best ASW weapon in the game. It drops a powerful type 40 torpedo up to 16.8 miles away--far enough to reach *most* distant Pelamida sub contacts. The type 40 reaches speeds of 70 knots, making evasion difficult.
Employing the -27 effectively requires a good solution. The Auto-TMA is (regrettably) usually good enough to place a -27 within acquisition range after 2 bearing lines. Aquisition, however, is not good enough for a kill, since the type 40 is easily decoyed. However, refining the TMA with a 2nd leg before firing will get rid of the error enough to deliver an extremely precise strike. Aim slightly in front of the target submarine...to decoy effectively he will have to turn the boat around, if the torp lands too close for him to get the boat turned it will be a guaranteed kill.
That sort of precsion is difficult, however, against a manuevering sub. For more slippery targets, fire a "bracket" of three missiles in a triangle shape around the target. Use a tight triangle if you are very confident in your solution; open it up if you aren't sure. It will be very difficult for your target to decoy torpedoes from three directions.

The -27 can also be used to assist a 65cm torp attack. Try firing a -27 ahead of the evasion route of a sub running from your 65cm torps. This will effectively create a bracket or pincer attack at a critical moment.

The Starfish and Stallion have the peculiar minimum depth of 50m, and max depths of 150m and 350m respectively. They drop the poorly performing UGMT-1 torpedo. This weapon has a pitiful top speed of 41 knots and a warhead so small that two hits will probably be required to kill a submarine. Akula drivers should only use the Stallion to hit submarines greater than 18nm away (the range of the SS-N-27). This weapon is usually only effective in a bracket attack, since it can be outrun and decoyed easily.

For Russian Kilo drivers that don't have the -27 available, the -15 is best used to compliment a torpedo attack. Since your torpedoes are easily outrun, you can use the -15 to have weapons attack the target from two or more directions. Of course, you can use tactic the -27 for this as well (if you have Chinese Kilo 368).

[Molon Labe]

The Shkval Supercavitating Torpedo:

The Shkval is a knife-fight weapon for the Akula. It has a speed of 200 knots and a range of 6nm, and a magnetic proximity detonator. It lacks a guidance system.

Because it is not guided, the shkval will not score a direct hit on your enemy. To use it, you must put several weapons close to the target...not only close by lateral distance, but also depth. While you can sometimes get an idea of whether a target is over or under the layer, depth cannot always be determined. So, you will need to fire a spread that can cover his manuevering AND depth possibilites. For this reason, the shkval is most effective in shallow water.

I recommend a 3-4 torpedo spread, centered 2-3 degrees ahead of the target, with the 2nd weapon 10-15 degrees ahead of the target and the 3rd 5 degrees behind. The center torp should be the shallowest of the spread. Engage at about 5.5 miles, and be sure of your solution.

Place yourself on a lag LOS before firing, and immediately accelerate and drop decoys after firing. There will likely be counterfire...your best bet is to no longer be on the snapshot bearing and for there to be another target (your CM) for the torp to acquire so the sub does not realize his mistake. Be ready with more weapons in case you only damage the target.

[Molon Labe]

Tactical Update: The Effect of Variable Torpedo Range (introduced in DW 1.04)

All torpedoes in DW 1.04 have a range-speed relationship. Maximum range occurs 10 knots below maximum speed, and is practically unchanged from 1.03. Maximum speed carries with it a 20% range penalty. Going below max -10 also results in a range penalty.

What this means is that ranges at which vessels could be successfully hit has been reduced. Perhaps more importantly, more players have become intuitively aware of the concept of "no-escape range" and have become more willing to use dragging (running out of range) as an evasion tactic, rather than trying to decoy and avoid the torpedo while remaining engaged offensively. So, in the world of DW 1.04, it is crucial to have an analytical understanding of no-escape range and to apply that understanding to torpedo employment.

No Escape Range Analysis
No-escape range is the maximum range your target can be from you where it cannot successfully drag a torpedo shot. It is a product of the speed of the torpedo, the runtime of the torpedo, and the speed of the target. You can imagine the concept as a ring contained within the ring representing the torpedo's range (at the torpedo's speed setting). The distance between the rings is a line representing the distance the target ship can run during the torpedo's runtime. At the end of the runtime, both the target ship and the torpedo meet at the outer ring. The implication is that if the target begins its run outside the inner ring, it will end its run outside of the outer ring, without the torpedo having caught it. If it begins inside the ring, the torpedo will overtake the target ship before it reaches the outer ring.

No escape range is mathematically expressed as:
(torpedo range)-(distance the target ship runs during runtime)
or
(torpedo range)-(target speed*runtime)
or
(torpedo range)-(target speed*torpedo range/torpedo speed)

The greatest no-escape range will always be obtained using the highest torpedo speed, because a successful intercept requires a high closure speed. Reducing an ADCAPs speed to 45 knots will knock your closure speed against a 30 knot target from 25 knots to 15 knots--a far greater price than the 20% range penalty.

For an ADCAP vs. an Akula II, no-escape range is 7.85 miles in 1.04. It was 9.82 miles in DW 1.03.

And because I know you all hate math as much as I do, I made this table (http://www.commanders-academy.com/forum/attachment.php?attachmentid=136&d=1190658378) for you, for target speeds of 17-40 knots.

Tactical Implications
Of course, the mathematical concept of no-escape range isn't the only thing that determines if your torpedo will have the smash to catch a fleeing target. The target may not run directly away, or it may slow to listen. It may need to turn before it can run. It also might not hear the torpedo right away, and won't start evasion until it finally does. All this makes the effective no-escape range further out than in the mathematically idealized case. Similarly, any time your weapon spends on a course other than lead pursuit pulls the effective no-escape range closer in; for example, snaking while the weapon is searching, chasing after a decoy, or error in the intercept course.

Against submarines, there are two main implications. The first is that subs are able to be more defensive than they used to be, and perhaps more significantly, players are more aware that they can use the drag tactic to ensure their escape from torpedo launched at range. This in turn means that to be able to torpedo a sub, you must be able to get very close, and you must do so without being detected. Obviously, since US subs have no alternatives to the torpedo, US sub skippers must become masters of stealth to succeed in this environment.

That sounds more daunting than it is. The US subs have a significant detection range advantage against the Russians, both in that the boats are quieter and that their towed arrays are more sensitive. This is especially true if you use the LW/Ami mod. In most acoustic conditions, a disciplined US sub skipper will be able to detect his opponent first and be able to close into no escape range undetected. This is true even for a 688I vs. an Akula II (in LW/Ami), but the margin of error is much tighter than it would be for a Seawolf vs. an Akula I(i). The two keys to making this happen are speed discipline and using the SSP. Speed discipline should be self-explanatory. As for the SSP, you want to minimize detection ranges so that you can get inside no-escape range before being counterdetected. This means being below the layer in a surface duct, being below the layer but above the sound channel in a convergence zone, and being close to the surface--but under the surface clutter (200 feet should do it) in a bottom limited environment (positive gradient). But, going below the layer and staying there can put the US sub at a disadvantage, because clever Russians (http://www.commanders-academy.com/forum/showthread.php?t=785) like to stay above the layer and let their towed array dip below the layer. If the Russian is above the layer and listening below, he will detect the US sub before the US sub counterdetects him. The solution is rather simple: spend most of your time below the layer, but come shallow occasionally to check for the Ruskie. When you go shallow, reduce speed, because you can be detected at a greater distance--just make sure you get the towed array into the surface duct and not just your boat.

Finally, always be sure to switch sides of the layer before firing the torpedo. Unless the target sub is listening on the other side of the layer (by dipping the TA as described or by using a UUV), this will give your torpedo a head start, pushing the effective no-escape range further out.

[Molon Labe]

LW/Ami and DW 1.04 Update: The Implications of Torpedoes Not Detonating on Decoys

In all versions of LW/Ami, torpedoes will not detonate on expendable decoys (but still detonate on towed decoys). In DW 1.04, the host has the option to set the % chance that torpedoes will detonate on any kind of decoy (this is done by editing the .ini file; unfortunately, there is no way to adjust or view the setting in the options menus).

The tactics already covered focused on keeping torpedoes off decoys to prevent them from getting blown up. In an environment where torpedoes do not explode on decoys, keeping the torp off decoys is less important and sometimes counterproductive. Since the sub can only drop decoys along its course, it effectively leaves a "trail of breadcrumbs" for the torpedo to follow to the target. Letting this process occur isn't necessarily a bad thing.

This does not mean, however, that you do not need to continue to track the target. The only time a decoy acquisition is a good thing is when it leads the torpedo to the target, and finds the target on the other side of the last decoy in the line. So, update your solutions to the target frequently, keep the torp headed in that direction, and when you get an acquisition, go to the sonar to note the exact bearing of the target at that moment. If the torp is headed away from that bearing (you check this from the Nav map by using the range circle tool), preenable and resteer it back in the right direction. The last thing you want is to give your opponent extra time by letting the torp run on anything other than an intercept course.

Once your weapon is in acquisition range, your opponent will try to evade by getting the torp to acquire a decoy, and then quickly moving out of the area behind the decoy where the torp will resume searching when it passes through the decoy. Your job is to get your weapon to search the right area. It's possible that you may be able to see the turn by checking the bearing on the sonar, but we're down to the final seconds, so there won't be much of an angular change to notice. But, if take note of where the decoys are being laid, you can make an educated guess about what your target is trying to do. (e.g. laying a line of decoys in one direction, then turning sharply behind it). You can either preenable and resteer the torp to that location right away, enabling manually once you pass the decoy; or you can leave the torp enabled and enter the course you want the torp to turn to once it passes through the decoy (the enabled torp won't respond to course change orders until it loses its track). Of course, if you have two weapons getting into lethal range at the same time, you can pretty much cover the whole area.

The Bigger Picture
When two subs are going head to head, there are several factors at any given moment to determine which sub is winning and which is losing. These factors include who has detected the other, the accuracy of the players' solutions, the range the subs are apart with respect to their weapons' envelopes, and how long it will be until a deployed weapon reaches a target. When a torpedo salvo explodes on decoys, the "score" changes drastically, because the defensive sub has the pressure taken off and can take the opportunity to catch up.

Without decoy detonations, a player is significantly less likely to be able to survive once a weapon gets within acquisition range (since if these weapons are spoofed, there is a significant chance of immediate re-acquisition). The players that are able to prevent an immediate re-acquisition must still deal with relentless re-attacks until the torpedoes run out of fuel. The pressure does not let up before then. There is little chance to play catch up.

If you use LW/Ami or play with these settings, the advantages you gain before the shooting starts will likely determine whether you are able to get a weapon on target. The best torpedo shooters will be those who are able to detect and localize their target the fastest relative to their opponents, and who are able to maintain that solution until the torpedo is able to home. Those skills end up being much more important than any tricks involved in wireguiding the torp during the endgame.