Question on gyroangle and torpedo 'turning' (point and shoot)
 

Greetings

a noob with a question here.

I have manual targeting enabled and weapons officers does NOT provide me with his assistance.

So...

Some time ago I realised the point of gyroangle: when it read 000 it is the perfect time to let the eel free. Then the torpedo launches exactly staright forward from the u-boat's hull and hits (hopefully) the target.

But now I'm confused again.

I discovered that the torpedos can align themselves towards the target. So after I have set all the needed data into the TDC, i don't even need to care about the gyroangle, correct? Even if I am in a shooting position with 90AoB, and the target has already passed the point at which my u-boat's hull is facing, I can just move the periscope over the target, fire the torpedo and it will turn towards the target! I guess this is what is called 'point and shoot'.

So since the torpedos seem to automatically turn towards the target, why bother with the gyroangle?

Or what fundamental am I missing here?

Thank you in advance!

The gyroangle is the setting on the eel that tells it which direction to head off in. 000 is optimum because the torpedo would travel a short distance from the uboat before making it's turn. The larger the turn, the less accurate it will be.

Hope that answers the question, if not, someone with more experience will probably be along shortly to clarify things.

Like previous fellow wrote... Higher gyroangle are more likely to affect the accuracy negative. The myth says that you should keep within ±10 degrees to get the best results. I don't know...

I always fire for a stright run though, since I don't have to bother the distance when doing that. In that case I have to fire when the ship is at 0 gyroangle.

Thanks a bunch, your answers clarify things. :)

By the way, do you know how large is the angle that the torpedo can turn when launched? Is it something like 45 degrees?

I thought it's handy that a torpedo can turn a bit, for example when attacking a convoy and you want to destroy multiple targets. In that case wouldn't it be very slow to start turning your whole u-boat towards the next target and shooting and again towards the next target and shooting... well I don't know yet how to deal with convoys. But in that case it could be handy and fast to 'point and shoot'.

But yeah when hunting a single ship it is arguably the best solution to shoot a 'direct' torpedo (gyroangle 000).

For convoys I line myself up ahead of the convoy at 90 degrees to the convoy course, turn my scope to till 0 gyro is indicated, then as the first row (abreast) of the convoy crosses my scope I fire. The furthest away will cross first etc. All torps should impact within a few seconds of each other giving insufficient time for the merchants' evasive turns to have sufficient effect.

Then it's time to avoid the escorts - but that's another story.

Actually trying to hit a row of a convoy is just as simple as hitting just one target in the 90 degree attack situation. You just wait until each bow passes the line in your periscope (but the 1st mast usually is a better margin of error), and fire 1 torpedo (per target). First the furthest collumn, and the nearest last. Those targets should get hit at about the same time.

But J3llyfish talks about torpedos that turn 'on their own'. Well those are advanced torpedos. That have extra gyro mechanisms that make it turn after a certain distance. Well, that means it's not really 'on their own', since set the extra gyro angles. Those only come available later in the war. The really advanced torpedos have an accoustic seeker. They are capable of finding their own way to the target. Or you if you are in the wrong place.

You should keep 2 things distinct. 1: how your Uboat is pointed in relation to the target's course, 90 degrees. 2: what the AOB looks like when you look at the target. If the target is passed the 000 bearing then his AOB is not 90 anymore. It's only 90 degrees when straight in front of you.

That said, yes, you can aim at him even if he is passed the periscope bearing that makes the gyroangle 0. (you could call that 'late') As you turn the periscope the AOB is updated in step. (assuming the TDC switch is on AUTO) And so will the new lead angle, as indicated by the new gyroangle. Range however does not get updated, and this is what gains in importance if the torpedo needs to turn because of the gyroangle. Short range needs a bigger lead-correction, however the appearant size of the target increases dramatically with shorter range aswel. In the end it depends on how long the target is by itself if you are likely to hit it.

I however have hardly had succes with such shots if I was late to fire. (Bernard being around the corner and all that ;) ) The target's size becomes a smaller angle again as the distance is increasing and the AOB increases beyond 90 degrees, which makes it easier to miss. On top of that the torpedo needs to catch up with the target, making it arrive later. Which means more time for the following to happen. If the target spots the torpedo (like with the bubbles of the type 1) then he only needs to make a small course correction to avoid it. As was suggested (the 'myth') you have some leeway, like a gyroangle between 350-010. But more than that and odds are less in your favour.

BTW, in my book 'point and shoot' is more like the simple automatic targeting. But I guess 'free aiming', as opposed to the target passing a predetermined point for which the periscope is set up, can also be considered like that.

Certainly more than 90 degrees. I've done enough 'parallel course' shots with succes. I guess 120 degrees atleast . According to the manual more as the technology advances. It also states the accuracy dimminishes, but I'm not sure if that is really the same as the gyro angle issue (a.k.a parallax aiming error Wiki-Link)

Thank you once more, everyone. :)

I think i got the hang of it now. At least in theory! :hmmm:

If I launch the torpedo before or after the 000 gyroangle, the range won't be the same as entered in the TDC (in the 90AoB method). That is something I didn't realise to take into account previosuly. And in the moment of impact the torp wouldn't anymore hit the target in an angle of 90 degrees.

Now I must ask one thing about the convoys.


..............3 ...........2 ..........1
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.E .................................................. E
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.................................................. .....................^
.................................................. .......my u-boat |



The E-arrows indicate escort ships, so there are two of those. And then there are 9 merchant ships (indicated by the arrows pointing to the right, and the convoys is moving to the right). And there is some space between all the ships indicated by vertical lines.



As i read what all of you said about convoys, i gathered the following:

In a situation as above, I'm suposed to only shoot the 1st deep row of merchants (the ones I underlined)? The furthest ship would cross my 000 gyroangle first, then the second and the nearest last?

And ideally, the torps would hit their targets nearly at the same time. Immediately after that the escorts would be after me.

So the question: is it (in practise) impossible to try to sink any ships from the 2nd or 3rd deep row? :06:

(i.e. if there were only 3 merchants in that convoy, those that are one after another between the 2 escorts, I could only shoot one of them, because there would be no time to wait for the others to cross my 000 gyroangle since the escorts would be too quickly after me)

Gyroangle itself does not mean a lot. It's the combination of AOB and Gyroangle that means something, at least for impact shoots.
What is true, is that you can't hit successfully if your impact angle is over 20°. Usually, if using the 90° AOB method you'll fire with a gyroangle between 345 and 15, to preserve a security margin.
If you use a 75° AOB as I commonly do against convoys (it opens your fire angle) you will fire with a gyroangle between 0 and 30.
But if I target a single ship I don't really care of my AOB, I mean the absolute value of the AOB, as soon as I got a reliable value, I just adjust my gyroangle accordingly.

No, you do not wait until the target passes the 000 gyro angle. In other words, that would be when he is right in front of you. Instead, you want to turn the scope until the gyro angle reads 0. Then the periscope bearing is something around 350 (in your example above) depending on the target speed and torpedo speed. When the persicope is there you are looking at a point that is slightly further away, but it is negligible. Now you wait until the target passes the periscope line. Because you look to a place before the impact point, the torpedos have just enough lead time to get there while they run straight out of the tube.

That is a possibility. Haste is of the essence while the torpedoes are still on their way. Give yourself some time by not shooting at the nearest column ship. Or atleast with some extra distance to give you time. If the target speed is dead accurate then you can hit almost into infinity. (well, if the tubes are open in time)

It's possible only if you let the 1st row go, and wait for the 2nd, or 3rd. But with the above way not at the same time.

If they are indeed in-line behind each other then yes, you would have to swing the scope to point at the other. So this implies the need for a range setting for each individually. Depending on your distance to the target track and the gap between them the difference between the two gyro angles could be substantial. The closer you are the bigger it gets. You'd want the gyro angles to be equally centered around 0 degrees for a (theoretically) simultaneous hit. But that means distinct range settings for each. How much depends on the geometry and speeds involved. You could try to measure it at the time, but targets swing by very quickly in those situations so you 'll never have it exact and on time.

If you know the (halve) gap distance, and your distance to the track then you can figure out mathmatically (with the TAN function) the halve of the angle between targets when they are in front of you. So now the periscope bearings are equally centered around 0 degrees, and you can do with just one range setting that is equal for both targets on either side. However, now the torpedos won't hit at the same time. One is partially head on to the rear target, and the other has to catch up to the front target. Giving the front target time to react to the attack. How much time requires a calculation based on the geometry and speeds involved.

Instead I advise to just keep your focus on one at a time. Certainly as a beginner. It's exciting enough.

P.S. Ascii art doesn't really work in these message windows. I suggest you put it between [co de] [/co de] tags. (remove the spaces, I put them in so it wasn't interpreted right there)

I see what you mean.

I'll be relying back on this information when I encounter convoys - in my current campaign it's still 1939, so thus far it has all been happy times! :D

Gyroangle is one weird thingy. I hope I will learn to better comprehend it as I play more. It must be all so easy when you know these things. :know:

It didn't come at once! Granted, being a math and physics nut it comes easier, but I still needs some effort to visualize it. But I'm sure you'll get it eventually too. If not allready.

I was hoping to include this picture when describing the above method. But I couldn't remember where to find it:

http://www.subsim.com/radioroom/show...0&postcount=47

Thanks! :up: