Manual targeting: need an explanation.

[CaptainAsh]

I m playing with full manual targeting for ever and I always worked fine as I m calculating my solution on the the navigation station.
Now I m wondering about removing the update contact on map option and computing my solution only from UZO or attack periscope. I m training with the option to check my estimation with the map right now and I m already efficient to get a good AoB and speed but my range estimation is often wrong by 10 to 15%.

I m reading everywhere that range is not really important and I need someone to explain me why.

[Maraz]

I m playing with full manual targeting for ever and I always worked fine as I m calculating my solution on the the navigation station.
Now I m wondering about removing the update contact on map option and computing my solution only from UZO or attack periscope. I m training with the option to check my estimation with the map right now and I m already efficient to get a good AoB and speed but my range estimation is often wrong by 10 to 15%.

I m reading everywhere that range is not really important and I need someone to explain me why.

Please remember that all stuff about targeting is about finding the correct gyro angle to hit the ship.

Now, range is not important as long as you shoot with low gyro angle. That's because the distances done by the ship and your torpedo are always proportional, so whatever the distance is, the launch triangles have all the same shape (angles) though of different size. So the gyro angle is the same, whatever the distance.

(sorry I cannot explain it better, but with a piece of paper and a pencil you can quickly convince yourself)

BUT if your gyro angle is large (say more than +/- 30°) there is the effect that the torpedo only takes the right direction after a certain distance (reach) from your boat. So the gyro angle must be compensated for this. And the compensation depends about how far the ship is. That is a amall effect though (but is more noticeable when the ship is closer), and I don't believe it alone can cause a miss.

Maraz

[CaptainAsh]

oh!!! it s just Thales! got it!

[Umfuld]

But distance is important for measuring speed though, innit?

[CaptainAsh]

Not really :)

There is a way realy accurate if you re not moving. Put you periscope in front of your target, start the chronometer when the ship cross the crosshair, stop it when the target quits the crosshair. Check your identification book for the target length. Divide it by the amount of second and then x 2. You got the speed :)
It s really efficient and work with any AoB and you don t care about the range. Of course the more closer of 90° is the AoB, the more accurate is the speed you got.

[ronbrewer]

Thanks for that info, CaptainAsh. I'm going to give that a try this weekend. I have two questions, though, just to make sure I don't mess up the procedure:

1) Will you get the same results if the target is 2000 meters away versus 800 meters away? Basically, since the ship is smaller at 2000 meters wouldn't it travel through the crosshairs faster or is this where I'm just not understanding the physics of the procedure.

2) Does it matter if you have the periscope on zoom instead of normal magnification? This question is similar to question 1 since zoom creates a larger ship image.

Thanks,
Ron

[Maraz]

Thanks for that info, CaptainAsh. I'm going to give that a try this weekend. I have two questions, though, just to make sure I don't mess up the procedure:

1) Will you get the same results if the target is 2000 meters away versus 800 meters away? Basically, since the ship is smaller at 2000 meters wouldn't it travel through the crosshairs faster or is this where I'm just not understanding the physics of the procedure.


Yes same result.


2) Does it matter if you have the periscope on zoom instead of normal magnification? This question is similar to question 1 since zoom creates a larger ship image.



No, it does not matter.

Basically, if your sub is not moving and you don't move the periscope, you are looking at the same point in the sea. So you are measuring how much time the ship takes to pass that point with her whole length. This has no relation with your distance from the ship and how big she is in your scope. E.g.: if the ship is 100m long, you are measuring how many seconds she takes to make 100m. Hence you can compute speed (V) given space (S) and time (T): (V=S/T)

This does not work if the ship is coming towards you or is going away from you with a small angle, of course.

Maraz

[Heibges]

Most times early in the war, you can get speed with the Matching Speed method hours before your actual attack.

A torpedo will intercept all targets on a Specific AOB and Speed regardless of range.

[P_Funk]

but my range estimation is often wrong by 10 to 15%.
How are you getting your range? When I'm surfaced I use the Watch Officer to give me range up to 100 meters and I use to the stadimeter to get it more accurate. That way I know its usually right so long as the stadimeter reading is inside the same 100 meters that my watch officer told me.

Range isn't that important but its helpful, especially for plotting the target's course and getting his speed that way. I as often as possible prefer to get the target's course and speed by plotting his position on the map and using a timer. That way I can monitor his course for an extended period of time and use multiple observations to get a concrete data base. This isn't necessary for lone merchants, but for a convoy its nice since you can just take target course and figure out the AoB. Thats good for night attacks when the ship profile can be hard to see.

AoB calculation from Target Course is:
Target True Bearing (Bearing Due North) - Target Course +/- 180

Target True Bearing = Target Bearing - Your Course

That can be useful for planning a surgical convoy attack or, if you're like me, have a crappy monitor.

[GoldenRivet]

I determine angle on bow after i have estimated the course of the target.

1st i draw a line with the ruler tool to represent the course of the target... this line stretches out about 2 or 3 miles ahead of the target boat.

2nd i use the compass tool and start out ahead of the target... move to the bow of the target, then move to my boat.

The angle presented in the compass is your AOB every time.

i determine speed either by timing between two points for one or two minutes, or by how long it takes the lenght of the ship to pass through cross hairs method but i find this cross hair method usually only accurate at about a 90 degree intercept angle.

Range i determine with the scope or UZO range finder.

attacking a few ships at a time in convoy is pretty easy because all you really have to change is AOB since you know they are all going a set speed. Switch targets in the scope, change AOB leave everything else the same and fire.... move to the next guy.

[P_Funk]

attacking a few ships at a time in convoy is pretty easy because all you really have to change is AOB since you know they are all going a set speed. Switch targets in the scope, change AOB leave everything else the same and fire.... move to the next guy.
Exactly. It would be even easier if the Devs had made the TDC accurate to the German one since apparently they had a "Target Course" dial that you could enter. This would allow you to enter the course for the whole convoy and not have to change anything and just point and shoot. Alas that isn't possible.

But what I like about using the AoB equation is that I don't need to mark anything on the map once I know the course of the target. Just to a quick calculation right before i fire and I have all I need. If I have two targets I can to the calculations at the same time and change the numbers immediately.

But a range of different methods is always nice to have since every situation is different.