Firing a salvo at multiple targets

[Pepe le Moko]

Okay i have become fairly good at launching torpedoes manually without the weapon officer's assistance and i got a decent hit ratio. But when it comes to shooting a salvo at several targets i can't seem to get it right.

Maybe i should explain a bit the way i do it. Hmm so i usually use the fast 90° method where i plot the target's course then position myself ahead of the ship i want to shoot at, at a 90° angle or closer to 45° when using magnetic torpedoes.

Now i have read that when you do that and your periscope is pointing at 0 or 180 bearing then you can switch the targeting computer back to auto and when you move the scope, the firing solution will be adjusted on the fly.

When firing at multiple ships though, when you switch to the second tube does it reset the firing solution? or can you simply adjust the range and fire like that?

[Pisces]

Yes, it keeps the settings that are in the tdc. Moving the scopes updates AOB. But not range, if the next target has a bearing far away from the bow or aft, and a significantly different range it needs to be adjusted (by you) aswel. Only torpedo depth and impact/magnetic setting is retained for each torpedo. The torpedo speed selector should also be retained for each, however there is a bug in silenthunter that forgets to update the speed switch if you select another torpedo with different speed (resulting in a faulty lead on the target). I am not sure about the salvo dial as I never use it.

[Pepe le Moko]

Thanks, i am curious though and wonder how other people do it.
I'll try this method more but so far the only way i have managed to hit several ships in one salvo is to position myself between the lanes of a convoy and fire my forward tubes at a ship and the rear tube at a different one.

[Pisces]

I am not sure what your problem is. You seem to be doing it correct.

First, what exactly do you mean with salvo? As far as I know 'a salvo' as defined in the manual (or performed in the game) is multiple torpedo's fired at a target at once with a small spread angle. For a succesfull hit the amount of this spread is very much dependant on range(at hit time) , target length, and AOB (at hit time). To get an idea, 1 degree of spread makes the torpedos move apart 17.5 meter for every kilometer. Compare that to the length of the targetship to estimate how far you can fire a 1 degree spread, or the maximum spread allowed to hit within the target length at it's range. AOB other than 90 makes the target look smaller and so also allows less spread angle.

Or do you want to fire just one torpedo at each of multiple targets (all at different bearings)? That is no problem, as long as the periscope/uzo is pointed to each target, and each target is fired at with the appropriate range setting.

[Pepe le Moko]

Yes the later, i want to be able to fire a torpedo at several ships in a convoy, empty all my tubes then dive and try to escape.

Let's say you plan to launch the torpedos at the main target when it reaches the 0° bearing, right in front of your U-boat and you also want to fire at the ships that are in the same column in the convoy forward and aft of the main target. That means you have to work out the range for all the targets beforehand, right?

For instance, you have worked out that the range for the main target will be 1km and the ships in the column are 500 forward and aft of this main target, you cant launch the torpedos at the main target then pause and find the range for the secondary targets, you have to know this beforehand? If they are in the same column, it probably won't be much different but still...

Now if you want to fire at ships that are in a different lane or column, how do you make it so the torpedos hit their targets, roughly at the same time?

[RoaldLarsen]

Originally Posted by Pepe le Moko

Yes the later, i want to be able to fire a torpedo at several ships in a convoy, empty all my tubes then dive and try to escape.

Let's say you plan to launch the torpedos at the main target when it reaches the 0° bearing, right in front of your U-boat and you also want to fire at the ships that are in the same column in the convoy forward and aft of the main target. That means you have to work out the range for all the targets beforehand, right?

For instance, you have worked out that the range for the main target will be 1km and the ships in the column are 500 forward and aft of this main target, you cant launch the torpedos at the main target then pause and find the range for the secondary targets, you have to know this beforehand? If they are in the same column, it probably won't be much different but still...

Now if you want to fire at ships that are in a different lane or column, how do you make it so the torpedos hit their targets, roughly at the same time?

Firing at three or more different targets in the same column in a single salvo makes a lot of work for you. To get hits on multiple targets, you need to have an accurate reading for target speed, but all the ships in a convoy should be travelling at the same speed, so you only need to get that reading once. Where the extra work comes in is you will also need accurate range for each target that you fire at with a gyro angle other than 0. This must be the range to target at the instant of firing.

It is not easy to work out the range for multiple targets in advance, though if you know which column they are in, and your boat is stationary, I suppose it can be done. However, to use predetermined ranges, you must also have predetermined gyro angles. The more the gyro angle differs from 0, the more important it is to have a precise range reading. If you are waiting for targets to come to predetermined gyro angles, why not wait until they are at gyro angle 0, and skip measuring range?

You can make things a bit easier for yourself by having one or more targets that you dont need to get the range for. If you fire at a target when the gyro angle is zero (not the target bearing, you don't want to be shooting at something that is directly in front of you unless it is not moving.), it doesn't matter what the range is. So if you must fire at three or four targets in one column, I'd suggest firing at two or more when the gyro angle is at 0, perhaps with one or two other targets in between. The downside of this is that it takes a considerable amount of time between the first impact and the time you can make your second shot at gyro angle 0. For an 8 knot convoy with 500m spacing, and a range to target of 1000m, you have to wait more than a minute after the first impact before you can fire the last torpedo.

I rarely fire at more than two targets in a single column with the forward tubes, as it requires too much exposure to get all those required range readings and/or too much waiting around before the final shot.

There is a much simpler and safer way to attack multiple targets. Use fast 90 shots on different ships all in the same row. This way you don't need to know range to target at all, just course, speed and spacing. Assume an 8 knot convoy with 500m spacing, and sub stationary and perpendicular to convoy course at least 350m from track of closest column, with TDC set to fire with zero gyroangle, synched to scope, which is stationary at 15 degrees bearing. You fire an electric torpedo straight ahead when the ship in the fourth column from you crosses the crosshairs, drop your scope and fire another electric torpedo every 32.7 seconds. All four torpedos will impact at the same time. If you don't know spacing, you'll have to sight each shot, to be taken when the respective target is at 15 degrees.

That's the theory. I've never actually done this, because by the time I figured it out it was too late in the war to be getting good looks at ships four columns away. Also, I don't like my sub to be stationary. I prefer some forward motion so I can get away faster. Forward motion delays the subsequent firing times however.

My typical convoy attack in '43-'44 involves 1 fast 90 with electrics and one ranged non-zero gyro angle shot with steamers on a close target. Sometime I will make two fast 90's on adjacent columns, with a ranged shot in between. If visibility is such that I am not worried about steam torpedos being spotted, I may fire my first of two fast 90s with steam and my second with electric to minimize the time between firings.

With hedgehogs out there, I figure I might not get quite as many sinkings per salvo this way, but I will get a lot more salvos, because I won't get sunk. It has been 86 patrols since I was sunk by a convoy escort.

[Kubryk]

Let's imagine you're interested in 3 ships, sailing west, one after another

///////////dis1///////dis2///////
<---Ship1-----Ship2-----Ship3
____________|
____________|d
____________|i
____________|s
____________|3
____________|
__________Uboat___________

You must gather information and be very precise. You need to know exact distance between ships (distance 1 and distance 2 in my crude drawing above). In a convoy dis1 should equal dis2. You may also want to know the lenght of ships, but maybe it's just me. Anyway, prepare to shot at a middle target when gyroangle is 0. Let's say you know you'll be 500m (dis3) from a spot middle target is going to sink at. You must now get bearing to targets 1 and 3. There're two options - you may wait for targets to pass you, note all data and make another round of moving ahead of convoy in order to take position for a perfect shot. This may take time, so you may want to use math. Just estimate by drawing. Using SH3 tools draw line representing ships route 500m from you, mark spacing for ships (you can use ships lenght, it may be important with big tankers). Use protractor tool - click on your imagined course (you're in dead stop), click on uboat, click on a place where ship 1 will be. You now know angle that is bearing. 360-angle = bearing for 1st ship, 0+angle = bearing for 3rd ship (if you're attacking from their starboard it's 360-angle for 3rd and 0+angle for first).

(that means - when you fire your torpedo for middle target, bearing to ship 1 would be 360-angle, for ship 3 would be 0+angle. At those bearing those ships are going to be when your first eel would be leaving your boat).

With ruler measure distance from uboat to both places when target 1 and 3 would be (distances should be equal, AFAIR in my last encounter when middle target was 550m ahead of me, others was 700m, distance between ships 450m). Now all you have to do is:
1. fire torpedo at gyroangle 000 for middle target
2. go to TDC and change distance for a proper one (you may want to add 50m compensating for time delay)
3. move your scope at target 1, fire
4. move your scope at target 3, fire
5. run as hell

Remember that in SH3 there seems to be bug - when using ruler, if number changes from 0,3 to 0,4 it really is 0,35 when it reads 0,4. It's easy to overcome this though.

This procedure is, for now, my way of attacking multiple targets at once. Good thing is - they don't have time for zigzagging. Bad thing (maybe, not for me) that torpedoes won't hit in same time. But again, time delay is going to be minor, so your targets won't escape.

It can be done - I did it yesterday, I hit 3 ships in a column. Middle one sank immediately, one got listed with dead engines, one was flooding making 1 knot. Two hours after an attack I surfaced and finished both dying ships with deck gun.

One more thing - from my experience it is best to shoot with this settings:
middle target - contact impact torpedo, ca. 3,5-4,5m of depth
other targets - magnetic detonators - because torpedo is not going to bounce and it kind of compensates for errors in your calculations.
That means that before actual attack you must set torpedo data in TDC and remember which torpedo to use for which target.

Hope I helped a little.

Edit: if you know triangles and stuff like that you can calculate everything withouth drawings. I suck with math so I draw