Simple question plus pro navigation quesiton in here

[Machariel]

Sinple question here: I'm in my 6th patrol Again I'm sent to AE98, some nowhere place where nothing happens. Is this normal? Or am I supposed to go through the motions for 24 hours to complete the primary objective, but after that roam as much as my fuel can take to find some kills?

Now something real. You veterans are going to cum on this one:
How do I accomplish an interception course which meets requirements. Usually they are: at 1500 meters, 90 degree angel. My ship is, say 50 KM away from whoever, I'm at x knots submerged, the other is at y knots, pls help with formula/procedure to align properly. I'm willing to learn so have a go at it. Also, what is the correct terminology for aligning tactically to get that 90 degree angle at a certain distance?

The assumption is that I know the speed, range and the (global) direction of the target ship.

[bstanko6]

the game sends you to a zone for 24 hours just to send you somewhere. You dont have to follow that. In the DEF we usually get a 2 week patrol.

Your second question.

First, being submerged you will not intercept anything because you are too slow. You have to surface, and either start the 4 bearing method, or stalk your target (run parallel in an attempt to find course and speed). Once you have the course and speed, you can now plot out your "ATTACK COURSE".

The 90 degree method is solid, so if your target is traveling say north 0 degrees, then you have to attack the ship at 90 or 270 degrees. The real challenge is figuring the target ships speed out so you can plot where he will be in a certain amount of time. Once you have this, you can calculate what speed you need to travel to successfully overtake him, and be in a forward position of his track when firing the torps.

And you are wrong, 1500m is not where you want to be, go for inside 1000m. This will eliminate errors from your calculations. And attack at night!

Ill send you a link on how to.

[Machariel]

the game sends you to a zone for 24 hours just to send you somewhere. You dont have to follow that. In the DEF we usually get a 2 week patrol.

Your second question.

First, being submerged you will not intercept anything because you are too slow. You have to surface, and either start the 4 bearing method, or stalk your target (run parallel in an attempt to find course and speed). Once you have the course and speed, you can now plot out your "ATTACK COURSE".

The 90 degree method is solid, so if your target is traveling say north 0 degrees, then you have to attack the ship at 90 or 270 degrees. The real challenge is figuring the target ships speed out so you can plot where he will be in a certain amount of time. Once you have this, you can calculate what speed you need to travel to successfully overtake him, and be in a forward position of his track when firing the torps.

And you are wrong, 1500m is not where you want to be, go for inside 1000m. This will eliminate errors from your calculations. And attack at night!

Ill send you a link on how to.
Yes, I am subscribed to your channel since I got here, and took a peek at the four bearing method, but I didn't understand it was useful for my question, which was a goal-orient attack course (so 1000m @90 knowing speed and direction). I'll check it out again!

[Kendras]

There are good tutorials here : http://op-alberich.forumactif.org/t7-tutorials

But you have to be registered on this forum to see the pictures.

[bstanko6]

Once you get the target course, you have all the information to set up an attack angle.

In order to set yourself up for that attack, is getting in front of the target, and having enough time to set your boat up for the attack. You need the target speed to get there.

So if your target is traveling 5 knots (1knot = 1.852 meters), then I know in 1 hours that target will travel 9.26km. I can adjust this number for 2 hours, 4, 48, and so froth. So if i want to be in front of the target, within 1000m close to it, taking into consideration the time of day, how far I am currently away from the target, if I have to at some point submerge, then I can determine how fast I need to go.

Just hitting Flank speed is great, but I want to travel economically, and get in front of this target without waiting an hour for it to travel to me. I cant go too slow because I need to get far enough ahead to set my attack up. I will make that my next video.

[Machariel]

There are good tutorials here : http://op-alberich.forumactif.org/t7-tutorials

But you have to be registered on this forum to see the pictures.Oooh solid!

[Machariel]

the game sends you to a zone for 24 hours just to send you somewhere. You dont have to follow that. In the DEF we usually get a 2 week patrol.

If don't accomplish the primary taks, will I still get my revenues?

[bstanko6]

Renown? No. you get them by sinking cargo.

[Machariel]

Renown? No. you get them by sinking cargo.
LOL then screw orders indeed (unless there's some good stuff to be had).
Where's the stopwatch in the nav room? I have only one in periscope/UZO. Or do I need a stopwatch mod or something?

[bstanko6]

MAGUI F is the mod I use, and it comes with a stopwatch in the nav map. You activate it in the UZO or periscope, and you can see it moving on the nav screen. Being that I hunger for realism, in campaign I use an actual chronometer.

[YellowFin]

Intercept course:

v_e = own speed
v_g = target speed
alpha = angle between target's course and target's relative bearing
beta = angle between target's relative bearing and intercept course

asin((v_g / v_e) * sin(alpha)) = beta


Go to map (F5)
Plot target's course with ruler
Measure angle alpha with protractor by clicking first on target's course, then on target, then on your own position -> alpha
Calculate beta with above formula
Select protractor, click on target, then on your own position, open angle until it's equal to beta
Follow this course to intercept target

[bstanko6]

That is the mathematical way to do that. But I find that with Weather, and veteran status of your target can affect your ability to use math to successfully attack your target. I believe math along with experience gives you better results. There is no disrespect to yellow fin.

[Sailor Steve]

Sinple question here: I'm in my 6th patrol Again I'm sent to AE98, some nowhere place where nothing happens. Is this normal? Or am I supposed to go through the motions for 24 hours to complete the primary objective, but after that roam as much as my fuel can take to find some kills?

Sometimes the game gets hung up and sends you to the same place over and over again. In real life you would be assigned to an area and told to stay there until further orders. If there was no traffic they would send you somewhere else. There is no rule that makes you stay there, or even go there, except the extra renown you get for doing so. If you're playing GWX even that is turned off.

One option is to use SH3 Commander, which lets you assign yourself your own locations.

[THEBERBSTER]

Hi Guys
Steve has come up with the ideal solution.
SH3Commander is an application where the player has the choice to play the area grid of their choice.
SH3C has many other aspects in it to enhance your gaming experience.

SH3Commander comes already installed in LSH3-2015.
Peter
https://s24.postimg.org/lmsfer8md/lsh3_support_download_banner.gif

[YellowFin]

That is the mathematical way to do that. But I find that with Weather, and veteran status of your target can affect your ability to use math to successfully attack your target. I believe math along with experience gives you better results. There is no disrespect to yellow fin.

The formula, which I found in a post in the german part of the forum, allows you to quickly determine whether you even have a chance at catching up with a map contact. If the angles and speeds of your boat and the target don't add up you will not get a result (i.e. an error on your phone or a calculator).

I use it to assess the feasibility and determine whether it's worth the time and how far I'd have to chase in a given direction. Looking at other map contacts and the general nautical and tactical situation (i.e. am I travelling home, how is the fuel situation, what are my orders, is it a valuable target?) I can easily decide whether to pursue or not.

There is also a graphical solution to the intercept course problem:

A sloppy description:


plot a line from target to our own ship;
plot target's heading from target;
select a factor to find a distance representative of target's speed, e.g. if target's speed is 6 knots -> 6 km (factor 1) or 60 km (factor 10) or 300 km (factor 50);
use the same factor to find the distance representative of desired intercept speed;
find first triangle by plotting representative distance for target on target's heading and by plotting representative distance for our own boat on the line connecting our position with target's position (start from target);
parallel move (i.e. copy) the third side of first triangle such that our current position is on it. This gives you a second triangle which shares two sides with the first triangle;


The last line obtained in the second triangle is the interception course.

A mathematically precise description:

km stands for kilometer
nm stands for nautical miles
1 nm = 1.852 km
1 knot = 1 nm / h
A = target position
B = our position
v_g = 6 knots (a typical convoy speed)
v_e = 11 knots (the speed at which you wish to intercept)
p = 5.4 (any factor that makes the plotting feasible and easy, see [1])
if m denotes a (geometrical) line |m| denotes its length (in km)


plot a line c from A to B;
plot a line b' with |b'| = p * |v_g| = 60 km in the target's heading from A. Let's call the end point of that line C';
plot a circle (with center A and r = p * |v_e| = 110 km). Let's call the intersection of the circle with line c (or its continuation beyond B) point B';
plot a line a' from B' to C';
plot a line a parallel to a' from B to intersect with b' (or its continuation beyond C') in a new position C;


a is the intercept course to interception position C.

This method basically pretends you're at a distance which is a multiple p of |v_e| and then graphically adjusts, i.e. multiplies or divides that distance to fit it to the actual distance you are at.

[1]
It doesn't matter what you select here. Note that you don't have to calculate a value for p. Just pretend that nm = km when taking distances on the map. You implicitly 'calculate' a value for p by simply plotting the sides of the triangle in whichever 'nice' number of units of distance you chose. That's the beauty of geometry, it works with ratios and angles and does not care about specific units or conversions. p only serves to make a' longer and thus easier to read out the intercept course, if p > 1. In practice select a factor that fits the map situation, e.g. p = *00 if you're 100 to 1000 km away from each other, and similarly p = *0 if you're 10 to 100 km away.

[Machariel]

Cool, this thread exploded a bit because it's an interesting subject. Intercepting is our bread an butter. For now, I'm using the "Intercept Theorem" from the French forum and practiced with that to see my options. I want an intercept persé, but I draw a line parallel to the enemy's route at 1200m distance, so I have time to set up the perfect angle. My plan is to practice that first, because you have to draw fast and accurate. the enemy ship is moving you know :)

Then, I'll move on the next methods here. Eventually I anticipate that none or 100%, but all of them combined will provide great insight. Practice is the key I noticed.

Two (three) things are needed to take into account: the moving ships and your sub operates at different speeds. It catches up and gets in advance on the surface for speed. But then it needs to go down, so your intercept-planning must take a slow moving sub into account for the next 5 km as well.

I'm only at mission 5 now (excluding the erprobungsstelle in SH3Commander), but I'm learning.

Edit: maybe I take a break and evaluate YellowFin's formula's first. I'm drawn to it like a seeking torpedo or something :03:


One option is to use SH3 Commander, which lets you assign yourself your own locations.
I play with this since the beginning (lol few days ago). How do I assign coordinates to patrol? I don't want to leave the 2nd yet.

[bstanko6]

But if you plan the attack at night you don't have to dive.

This is why I don't use the heavy math. As long as you know the target speed, and direction, you can plot when and where to attack. You can stalk your target until dusk with enough information.

[Machariel]

Ugh I need a stopwatch in the nav room badly. Is it easy to port the existing stopwatch in periscope room to the nav room?

But if you plan the attack at night you don't have to dive.

This is why I don't use the heavy math. As long as you know the target speed, and direction, you can plot when and where to attack. You can stalk your target until dusk with enough information.
Yeah, I most likely won't use the math either. But for the learning phase I think it's good to explore this subject, also from the mathematical perspective. I'm sure it will add greatly to the phenomena of "insight".

[YellowFin]

Obviously the interception course should not be used to basically collide with your target. The idea is to get into the general vicinity of the interception point.

Usually I do the calculation with a lower speed than I'm actually going to sail at or I adjust the course after calculation slightly s.t. I arrive earlier, i.e. I increase/decrease the angle s.t. my track gets shorter while I sail at the speed used in the calculation. This way I arrive on scene early and I can acquire the target either through spotting or hydrophone.

One of the two main methods of obtaining an attacking position described in the U.Kdt.Hdb [1] (an original tactical manual for Submarine Commanders published by the German Kriegsmarine) can roughly be summarized as follows:


acquire a visual or acoustic bearing of the target (by intercepting it)
move away or closer to target s.t. you can keep track of target without being detected. I try to keep the target at the horizon and almost completely faded out.
overtake target while taking frequent bearings in regular intervalls (every 5-10 min, and write down the time of the first bearing for the speed calculation later) and plotting them on the map. You don't need the distance to target at this point all though it doesn't hurt to keep an eye on it, in case the target changes course or speed
once sufficiently ahead of target (I usually got about 11 km in good visibility) turn in to cross its bow, while still taking bearings and plotting them
slow down as you approach 0° AOB, use recognintion manual to identify 0° AOB and plot this relative bearing on map. It will cross all the previous bearings you've taken and it represents the exact heading of the target. Knowing the length of the intervals and the time of the first bearing you can calculate a very good estimate of target's speed
dive and go on a course exactly opposite to the target's heading about 1.5 km off of target's track, at ahead 1/3
keep taking bearings to have an informed estimate of distance to target
Since you are on a course parallel to the target, relative bearing of target = AOB, verify using recognition manual
once the target is 2-4 km away turn in (for bow shot) or away (for stern shot) at 90°, slow ahead after executing turn


Check out my play through here (https://www.youtube.com/playlist?list=PLj2z2c5q-u0I5K-8v4iaURluoG5sM5AXb), where I demonstrate all the methods I have described.

Happy hunting :)

[1] A (partly inaccurate/confusing) translation of the original U.Kdt.Hdb (https://maritime.org/doc/uboat/index.htm).

[Kendras]

Did you manage to plot an interception course with the tutorials ?

[Machariel]

Did you manage to plot an interception course with the tutorials ?
I even made a screeny during the planning phase but I accidentally left the time compression on so I couldn't make a second to show the near perfect result! I used the "Intercept method" from the French forum! I'll post screeny of planning phase any sec. I'm totally excited.

Edit: added screeny planning
http://i.imgur.com/zX70S8M.png

The main thing I didn't account for is that when my ship was at 4.5 Km from the victim, I submerged, so my speed slowed down a lot. I need to find the visual geometric trick to compensate for that. I'll make it my standard to dive at 5Km distance from enemy. Secondly... I need to adjust for the time I need to get to periscope depth from, say, 30 meter depth.

Edit 2: Right now hasing that guy and trying again. This time I try to compensate for the both the items I mentioned above (slow speed due to submerging and loss of time due to going back to periscope depth at slowest speed). I'll try with a threshold of 1000 meter (was 200m, total of 2000 meters distance from interception point).

[Kendras]

Good job ! :yep:

[Machariel]

Near perfection, almost creepy. I was a bit too harsh on self-criticism in my screenshot. Next practice: YellowFin (http://www.subsim.com/radioroom/member.php?u=365048)'s math. I'm almost jumping from excitement!
(Notice that I assumed my speed as follows because I slow down due to diving: ((real_speed + 8knots)/2 ) * 1.1

http://i.imgur.com/VsjS1h9.png

Also, I notice the stopwatch-method (3m:15s of recording) puts the automatic periscope speed estimation to shame. Learning as you go.

[Machariel]

<snip advice>

Check out my play through here (https://www.youtube.com/playlist?list=PLj2z2c5q-u0I5K-8v4iaURluoG5sM5AXb), where I demonstrate all the methods I have described.

Happy hunting :)


I am now as I type this. Just a quick note: I see you have no Anti Aliasing as well. I just fixed mine. You're not interested in that? Cheers.

[YellowFin]

I am now as I type this. Just a quick note: I see you have no Anti Aliasing as well. I just fixed mine. You're not interested in that? Cheers.

Hey, thanks for your comment! Nice YT avatar btw :)

Is the aliasing the ugly fine lines that are shown as dashed lines, like the antennas and such? Yes, I'm very interested in fixing that.

[YellowFin]

Near perfection, almost creepy. I was a bit too harsh on self-criticism in my screenshot. Next practice: YellowFin (http://www.subsim.com/radioroom/member.php?u=365048)'s math. I'm almost jumping from excitement!
(Notice that I assumed my speed as follows because I slow down due to diving: ((real_speed + 8knots)/2 ) * 1.1

http://i.imgur.com/VsjS1h9.png

Also, I notice the stopwatch-method (3m:15s of recording) puts the automatic periscope speed estimation to shame. Learning as you go.

The forumla beta = asin(v_g/v_e * sin(alpha)) will not work with that correction, it assumes true persistent speeds (at the time of the calculation) until interception. Or are you calculating an average with your correction?

I take from your posts that you look for an approach course when you are already in visual range of the target. I use the intercept course formula for intercepting a map contact from a B-Dienst message, e.g. when a convoy pops up at the other end of the grid square, or a grid square over from where I am patrolling. That means they're usually dozens if not hundreds of kilometers away. With the intercept course I get into a range of about 5-10 km from the target's supposed track and then the tedious work of determining its exact speed and heading begins (combined with getting into an attacking position).

My method:

Get map contact from B-Dienst or friendly u-boat
intercept using formula until about 5-10 km from supposed track
check horizon, usually I have the target abeam, either slightly ahead (if I used the calculation tel quel), or behind if I made sure to arrive early
if no visual of target can be obtained -> dive and try to get acoustic signal
If you are way too early hunt up supposed track surfaced with intermittent dives if visibility is bad until target is found. To decide whether you're behind or in front of target, check time of map contact, the correctness of your calculations and whether or not the target might have turned.
once found, overtake by 5-10 km, turn in to get 0° AOB and obtain exact heading
move off track by ~1.5 km and approach slowly on an opposite but parallel course
turn in for shot at 90° AOB


If you want to go for the perfect, well prepared 90° angle shot I recommend you overtake your target by ~10 km. You can go down to ~5 km at night or in bad visibility.

Tactical advice from the U.Kdt.Hdb. :

(I'm paraphrasing)

Stay surfaced for as long as possible without risking detection. Speed and maneuverability are much better on the surface. The submerged movement is for the surprise attack only.


I still sometimes make the mistake of diving immediately after taking 0° AOB bearing. The smart thing to do is to speed up again (I usually slow down to make sure I don't miss exact 0° AOB) and take a position 1.5 km off track and turn for opposite but parallel course and then dive, because all this maneuvering while submerged takes a lot more time

In German engineering language we differentiate between dive-boats and submarines (ger. Untersee-), and according to this definition only types XXI and onward count as true submarines. Our U-boats (Type II, VII, IX) are meant to dive only for the actual attack and for evasion. They stay surfaced for most of the time.

I hope these tips are helpful. Have a nice weekend everyone!

[Sailor Steve]

I play with this since the beginning (lol few days ago). How do I assign coordinates to patrol? I don't want to leave the 2nd yet.
When you first open Commander there is a blank slot at the bottom left. Put the cursor on it and it says "Leave blank for SH3 generated patrol grid." Type the grid you want into that slot.

[Machariel]

Hey, thanks for your comment! Nice YT avatar btw :)

Is the aliasing the ugly fine lines that are shown as dashed lines, like the antennas and such? Yes, I'm very interested in fixing that.
I have only the day before yesterday solved mine. Here's the thread: http://www.subsim.com/radioroom/showthread.php?t=230507

[Machariel]

<snip tactics>


For the first question, yes I use a guesstimated average taking submerged speeds into account. The formula is only to develop insight. Eventually the graphical interception method using Thale's theorem can be done on a whim. So everything becomes relative after practice and experience.

I have practiced with the B-radio map contact through bstanko's YT channel. I can find the target if it's not too far away. But the hydrophone is too in-accurate I noticed compared to visual acquisition for approach angle. But I'll check this comment again and see if I overlooked something.

When you first open Commander there is a blank slot at the bottom left. Put the cursor on it and it says "Leave blank for SH3 generated patrol grid." Type the grid you want into that slot.
Yes, I've found it. It wasn't blank, it revealed where my next assignment would be.