Convoy attack tutorial

[ddiplock]

Hey guy's, does anyone know if there are any tutorials floating around that show how to do an attack on multiple targets in SH4, such as a convoy? I'd like to try and narrow down some pointers to try and get a better understanding of a multiple target situation, since the TDC in SH4 works differently from that in SH3....which made convoy attacks so easy

Cheers kappies

[Topo65]

This is the best one I saw:

[Frederf]

It looks like you're asking for how to target multiple ships more than how to attack a convoy in general so I'll focus on that.

General convoy approach involves getting to the front and to the side to start. You also want a pretty good idea of the convoy course and speed to +/- 5° and +/- 1kt. I used to sit with a heading 90 degrees from the projected course about 1500 yd from the course line as deep as I could manage (or worse at PD) silent and twiddle my thumbs at all stop until the lead escort passed. Timing the very slow rise to show up right when I needed to be there can be tricky even if you have a table of surface times.

A lot of time this approach got me detected. I severely misjudged the balance between low noise and distance/aspect when it comes to being found out. Coming in at 2/3rds with a low aspect and not blundering into sonar cones is a lot better than 0 knots beaming a Japanese sonar array.

One trick to getting good hits is to fire at the "magic angle" added to the typical 90° AOB. If a row abreast of ships in a convoy are going CRS 045°, SPD 10, spacing 1000yd you are tempted to fire a torpedo at 315° torpedo course (impacting squarely). There are two problems with this. First, earlier in the war impact triggers don't like hard, fast, square hits and may dud instead of explode. Hitting at 60°, 70°, or 80° TTA are more reliable detonations for both impact and influence triggers.

Second, if you miss the first ship at 90° TTA, there's no chance of hitting the next one in the row. In fact the "wiggle room" for error on a single target is usually best at a few degrees (10-15) beyond 90° mathematically. Imagine that each ship is a hoop and you want to fire a torpedo through each hoop, you're going to have to fire at the near hoop such that the torpedo has a component along the targets' course forward as well as across them to pass for the final hoop. The math is simple:

 Magic Angle = ArcTan( Target Speed / Torpedo Speed ) or with the small angle approximation Magic Angle = ( Target Speed/ Torpedo Speed ) * 57.3°/rad

The TDC with the settings: target speed, range infiinity, bearing 0°, and AOB 90° will also spit out this angle. For example a 46 kt torpedo against 10 kt targets gives 12.3°.

Against the earlier example convoy 10kts CRS 045°, instead of shooting a torpedo along a CRS of 315°, you instead point the point to a heading of 327° (315°+12°) and fire when the solution is gyroangle 000°. If you miss the first ship, you stand a good chance of hitting the 2nd, 3rd, or 4th in the row because you aimed at all 4 of them at the same time.

Get the EasyAOB mod and set AOB by known course in most cases.

Set all torpedoes to a good depth and speed before the attack. For impact I take the draft and divide by 2. The more work you do before the easier it is after. Make sure your recognition book is open to Merchants and even a page on or near the target you're going to attack.

Fire spreads of 3 or even 4 for large ships. Get plenty of coverage at ranges >1500m. Assume that at least one is going to miss but 1-2 will hit. If you try to make all 3 hit near center target then that's a lot of eggs in one basket.

ID all targets you can on the way in. Draw a little dot-diagram of the convoy (PPI radar helps) with labels of each one you ID. Put a slash through ones you hit and an an X through sinks. You can circle the 1, 2, or 3 targets you think about attacking this run even. IDing targets can take a while and make one feel too pressured or hurried during an attack leading to foolish shots or actions. Set depths for torpedos based on target or even write personalized messages to the individual crews of the marus.

PK is nice for checking your solution but not so good at firing with multiple targets. PK has a habit of evolving your good numbers into not so good numbers without asking you. Also Dick O'Kane method is much easier and more reliable for all this spreads at many distances and we've all forgotten to reset the gyro offset dial.


The Far-Near Attack is usually carried out with the forward tubes since you have more them then at the rear but you could do 2 and 2 from the rear. The Far-Near Attack relies on being able to hit the far target without hitting any closer so the whole magic angle stuff above can't really be used. You want to be able to see at least half a ship length between the far target's stern and the next closest's target's bow just to make sure. That is unless the far target has a deeper draft but that can be iffy.

One shoots at the far target (preferably a wakeless, battery torpedo) and waits until just the right time to shoot at the near target so they both impact at once. Typically this is done when the row has not yet passed and the far bow is seen ahead of the near target. If all fish are the same speed (say a fast MK14) then the math is easy. A 46kt MK14 travels 1000yds (typical lateral convoy spacing) in 40 seconds. If the far target is 2 columns over from the near target then 1:20 between launches. When in doubt wait 10-15 more seconds than you think you should. It's much, much better for the far target to be hit first. The near target has a much higher probability of hit even if he is spooked by the hits on the far one than the other way around. For more complex times set up both in the TDC and note their run times in the attack map.

Pro: Minimal maneuvering, minimal TDC manipulation, most free thinking time between spreads, large engagement window, light maneuvering restraints
Con: nearly gaurenteed not to get lucky hits, involves long range shots, torpedoes can be spotted in long runs in good weather, long runs increased premature detonations in poor weather

The Column Attack is usually done from the fore tubes but could be done from the rear tubes, giving 2 tubes per target. This attack targets two targets in column. The sub fires on the lead at optimal or past optimal angle and then immediately turns and engages the rear target.

What's nice is you can target any column if you're not worried about lucky hits. However, if you target the 2nd and 3rd rows of a column and there are other ships beyond your target you might get lucky and hit a ship from the 1st row or 4th row with any misses on your lead and rear shots respectively. Usually you have to sacrifice the quality of the shot in terms of angles in order to engage both in a short period of time but they are quite close so it balances somewhat.

The lead target should be shot first since it is the longer torpedo run in terms of time and as time goes by the lead target solution is getting worse while the rear target solution is getting better. The rear target will likely turn away which makes a nicer target but be sure to watch for this in terms of your TDC solution.

If you really whallop the first he may become an obstacle for the rear ship to have to steer around which can make targeting the rear target difficult. To keep some speed and depthkeeping you'll likely be moving at at least 1kt during the whole maneuver, likely more to facilitate a turn between targets. Make sure that you don't get too close to the column's course line. Being 1500m from the lead target might mean an 800m range on the rear target. A long shot on the front target also gives you more time to set up on the rear target before the first impacts.

Pro: Short torpedo runs, good PK solution check opportunity, light maneuvering constraints
Con: Iffy lucky shot chance, moderate TDC manipulation, maneuvering required, less than optimal individual target shots, second target likely maneuvers, short time between shots, small engagement window


The Front-Rear Attack is problematic when it comes to maneuvering the boat but can give very fast results with short torpedo runs. Unlike the previous two attacks this one requires exacting placement with respect to the convoy columns. At 1000yds apart there's barely room to shoot at both while keeping 1kt for depthkeeping and some turn ability.

One can generally setup "magic angle" during the initial phase of the attack on the rear target and let the gyro do all the work for the forward target. This gets you pointed in the right direction for escape and makes the harder shot happen first when you have more time beforehand. Angle also gives you extra effective distance for torpedo arming as well as making it a little easier to keep tabs on the rear column while targeting the front one. Attacking from the forward tubes first makes the most sense assuming you are traveling forward so you can get a decent amount of standoff for the forward target when you are nearly being rundown by the rear target.

Once the gyro angle reports a shot that will impact squarely or a little after, fire and immediately target the rear, often increasing submarine speed. There's a lot to do with TDC in a short period of time but a PK solution check is usually worthwhile. If you make a "phony" TDC solution for the rear tubes first (before attacking the forward target) you can memorize the angle that gives 0 gyro and simply use that. At close ranges and 0 gyro it's hard to miss if you fire 3-4 Dick O'Kane at this angle. Give plenty of coverage, especially to the rear as the target will likely be maneuvering after the forward target hits. Be aware that it takes a while for torpedoes to come up to set depth so range is good to 700yd or so. Gyro angle and the associated "projection" due to the initial turn of the torpedo means that gyro angle is a very big deal at short ranges. Firing 20° off bore at short range might mean at 30° gyro angle which can make very close shots miss.

Pro: Short torpedo runs, minimal maneuvering, low chance of detection, pre-positioned for escape
Con: Strict maneuvering constraints, rapid TDC adjustments required, short time between shots, maneuvering second target


Triple Crown is a name I just made up for the Far-Near combined with the Front-Rear attacks. I would imagine that I'd target the far using battery torpedoes on a pretty hefty gyro angle (30° or so) then spin around and try to hit the rear target (same row as the first) possibly already turned to be on its "magic angle" and then get the third target which is a row behind the first target in the same collumn. I think that's how the torpedo run times work out best in most situations.

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Overall I'd use near-far attack in good weather where I can't get deep into the convoy and when I have battery torpedoes. My confidence in the course and speed of the convoy would have to be very high (confirmed by PK over a long interval) and they couldn't be zig zagging.

I would use column attack in a faster convoy that I could get close to, especially in poorer weather. Most likely the targets would be small or medium.

Front-rear attack I would use if I have plenty of rear torpedoes compared to front or I have a really large target (liner, large tanker) that I want to use 4-6 torpedoes on and still want to pick up a second target with the rears. Good or moderate weather works best with front-rear attack. Really poor weather makes front-rear a headache and a hazard.

[Mush Martin]

The Patented Death Pirrouhette for the Big'n's

[captgeo]

cool SS......