Interception Technique Help?

[reignofdeath]

So first off I want to say thank you to everyone who has been practically holding my hand so far with this whole thing. :salute:

Secondly Id like to apologize for SOOOO many threads but Im trying to dive into this and learn and learning requires many questions to be asked by me :down:

But to the point, I would like to know the different techniques for interception. Im using one now in which I get a contact and general heading, draw a angle from the contact through my u boat, then in the direction of his general heading (if he is going east and Im north, then I cut the 2nd leg through his course which I map out wiht a ruler)

Then I draw a circle representative of his speed (slow is 6knots so well use that) then where that circle intersects his course I draw one rep of my speed. (say hes doing 6 knots and I feel like doing 7 or 8 so I draw a 8 km circle) then I draw an angle where my circle meets the 1st leg of the "Big angle" then I make the Big angle match the little angle and i have my interception.

However ive noticed that

A) Im quite inaccurate some times and in many cases must re adjust my positioning and

B) that for contacts far out (over 600km or more) that I seem to have trouble

(pertaining to B: In my current campaign I just got a report of a TF heading SE at 8 knots, however he was ridiculously far away, but since I hadnt seen any action yet Id figure id try, what I did was draw a 200 KM circle for the TF speed and a 300Km circle for mine (seeing as how I thought if I divide his speed as I lay it on the map by 4 mine would need to be also) <--is this wrong? and if so what is the general rule of thumb for how close convoys / ships/ etc should be for intercepts, AND is there another more efficient and better way to do long range intercepts??

and anythign else you guys can teach me would be great :arrgh!:

Casey

[Snestorm]

The only thing BDU occasionaly tells me about is convoys. (Usualy, I don't even get them).

They give me a grid number, direction (32 points), and slow/medium/fast.
I try to gain a position ahead of their most advanced possible position.
From there on in it's generaly alot of wide zig-zagging across their possible course until my lookouts see something.

[reignofdeath]

anything else you guys could reccomend?? :yeah:

[desirableroasted]

You mentioned 600nm... at that far out, even the tiniest deviation will mean you and the target will never meet. And since the contact information is vague ("West" for example, can be a heading of 259 to 281; "Slow" is 4 to 6 knts), deviation is built in from the start. Moreover, the ship will probably change course along the way.

I disregard any contact reports further than 100nm, and even those I think about carefully. If it is a single ship moving away from me, I am not going to burn fuel hoping to overtake it AND find it. If it's a convoy 60 nm away, though, it's worth the effort to overtake.

Of course, stuff moving toward me or laterally is worth investigating.

[Pisces]

(pertaining to B: In my current campaign I just got a report of a TF heading SE at 8 knots, however he was ridiculously far away, but since I hadnt seen any action yet Id figure id try, what I did was draw a 200 KM circle for the TF speed and a 300Km circle for mine (seeing as how I thought if I divide his speed as I lay it on the map by 4 mine would need to be also) <--is this wrong? and if so what is the general rule of thumb for how close convoys / ships/ etc should be for intercepts, AND is there another more efficient and better way to do long range intercepts??You choose a scale of 25 km/knot for the taskforce. (200/8=25) Then the radius of your speed circle would be 300km if you move at 12knots. (300/25=12) If you moved with any other speed then you would have been late or early for the meeting. To keep things simple you could have used a scale of 10km per knot. So circles of 80 and 120 km.

I made myself a rule to meet the target before the target has moved 175km. Beyond that he might fall outside of your hydrophone sensor range. (listening yourself) So I plot a target-course extension of 175 km and set a circle at the endpoint with radius 34km. Then I make an ice-cream cone out of it (add two tangent lines to the circle from the starting point) to show where he could be during the whole process. If I cannot make the intercept cross the flanks of that ice-cream cone, then I let it go. I never make a choice based on range to target alone. The intercept course needs to cross the ice-cream cone from whatever angle. That's the rule! Ofcourse, I don't expect to make a visual contact at the expected meeting point. As it is based on hydrophone range if you listen yourself. If you want to rely on visual range only (with GWX can be up to 16km) then reduce the ice-cream cone to a size of 82km. (41km if you use stock 8km visual horizon)

Intercepting stands or falls with knowing the right target speed. If you only have general speed indication (slow,medium, fast) then you have to guess. Slow is up to 8 knots (medium up to 12, though could be changed by a mod). So if you guess it to go 6 knots then you might find in the end that you are late to the meeting if the target was actually a bit faster. Worst-case speeds (highest) always make you arrive early. But it might also mean that you choose not to intercept those that in reality could be intercepted because of lower than assumed speed.

Unless you are really careful about your fuel-status, I'd go with full speed. (take into account in your drawing the actual speed that you will intercept with, like reduced due to waves and weather) Don't tarry and give the target time to make a course change. Make haste!

[reignofdeath]

The smaller circles would have made it so my circles wouldnt have converged and the way I know how to do it I need to have them converge before I can get an angle to lead the target with. and Could you maybe visually represent what you told me? I dont understand the 25 km/knot thing.. as well as in GWX on the right side of the Nav map there are scales how are they used??

You choose a scale of 25 km/knot for the taskforce. (200/8=25) Then the radius of your speed circle would be 300km if you move at 12knots. (300/25=12) If you moved with any other speed then you would have been late or early for the meeting. To keep things simple you could have used a scale of 10km per knot. So circles of 80 and 120 km.

I made myself a rule to meet the target before the target has moved 175km. Beyond that he might fall outside of your hydrophone sensor range. (listening yourself) So I plot a target-course extension of 175 km and set a circle at the endpoint with radius 34km. Then I make an ice-cream cone out of it (add two tangent lines to the circle from the starting point) to show where he could be during the whole process. If I cannot make the intercept cross the flanks of that ice-cream cone, then I let it go. I never make a choice based on range to target alone. The intercept course needs to cross the ice-cream cone from whatever angle. That's the rule! Ofcourse, I don't expect to make a visual contact at the expected meeting point. As it is based on hydrophone range if you listen yourself. If you want to rely on visual range only (with GWX can be up to 16km) then reduce the ice-cream cone to a size of 82km. (41km if you use stock 8km visual horizon)

Intercepting stands or falls with knowing the right target speed. If you only have general speed indication (slow,medium, fast) then you have to guess. Slow is up to 8 knots (medium up to 12, though could be changed by a mod). So if you guess it to go 6 knots then you might find in the end that you are late to the meeting if the target was actually a bit faster. Worst-case speeds (highest) always make you arrive early. But it might also mean that you choose not to intercept those that in reality could be intercepted because of lower than assumed speed.

Unless you are really careful about your fuel-status, I'd go with full speed. (take into account in your drawing the actual speed that you will intercept with, like reduced due to waves and weather) Don't tarry and give the target time to make a course change. Make haste!

[Pisces]

The smaller circles would have made it so my circles wouldnt have converged and the way I know how to do it I need to have them converge before I can get an angle to lead the target with. and Could you maybe visually represent what you told me? I dont understand the 25 km/knot thing..

Then I draw a circle representative of his speed (slow is 6knots so well use that) then where that circle intersects his course I draw one rep of my speed. (say hes doing 6 knots and I feel like doing 7 or 8 so I draw a 8 km circle) then I draw an angle where my circle meets the 1st leg of the "Big angle" then I make the Big angle match the little angle and i have my interception.I'm sorry, I can't think of a way to make it more visually clear. But you allready understand what I meant I think. In the bold text above you took a scale of 1km om the map to represent 1 knot of speed. But if you actually draw that then it becomes a teensy weensy drawing. Better to make it a bit bigger, that's all. If you make his speed larger by for example 10 times, then you should make your own speed circle also larger by 10 times to keep the shape. But you are right, it should not become larger than the distance to the target is now. Then your speed circle might converge with the line from target to sub behind your sub. It's still geometrically correct, but confusing for the eye.

By the way, it is not garuanteed that you can make the intercept. The 'Angle on the bow' might be too large (depends on the position of you both), or your speed is too slow, to ever make the intercept work. If this is the case then your speed circle wouldn't even touch the line from the target to your sub. You have to find a way to go faster or give up. Can't have everything.

as well as in GWX on the right side of the Nav map there are scales how are they used??The scales on the side of the (GWX) map are known as a 'nomograph'. It allows you to calculate speed=distance/time equations. You have to know atleast 2 out of the 3 values. Like speed and time with distance unknown. Then you can figure out how far you move after such time at that speed. Or time is unknown then you have to know speed and distance. But it really doesn't matter which one of the 3 is unknown, and which 2 are known. You'll solve it at the blink of an eye.

To do so, pick the line tool. Draw a line across all three scales. It wil be diagonal most likely. Place the endpoints such, that the 2 known values are crossed by the line. You will find that the unknown value is also crossed by the line. Now grab your calculator and check! ;)

Here is an example of a nomograph on it's side:

http://www.subsim.com/subsim_files/images05/nomobig.jpg

It shows:

top scale: time (minutes= 1)
middle scale: distance (0.8-ish kilometers)
lower scale : speed (25 knots)

25 knots is 46.3 kilometers per hour. In one minute that is 46.3/60= 0.77 kilometers.

[reignofdeath]

Ahhh okay ! Thank you :yeah: Well Im off on my NEW campaign and Im gonna see if I cant do better at intercepts. Next is manual targeting :hmmm:

[JokerOfFate]

:DL Looking good, but it is going to break your heart if you change back :D

[reignofdeath]

From manual to auto?? why so? lol

[JokerOfFate]

The feel of having total control :DL, and besides a human brain is always smarter than that of an AI.

Other than that I love going on my gut feeling and manual it just so free :DL:DL:DL:DL:DL

[reignofdeath]

lol nice

[fastfed]

The only advice I can give as I am still in progress like you.. Is its ok to make another go at it..

For example.. After all my planning of intercepting, I would be way off.. at P depth and trying to make a run to get into position.. Usually I waste all my battery and I have some not such nice friends after me (making all that noise)

I finally learned that even though I was way out of position.. I was usually in better position this time to make a good plot for the next time.. I would wait a couple hours till the convoy is gone, surface and get back in front of them..

Sometimes it takes me more than 2 times.. LOL but eventually I get it.

[JokerOfFate]

I go for lone merchants, and I never go too far out of my way to get a convoy, the thing is lone merchants mount up.:)

So go out there sit in a convoy route, and sink lone merchants till you find a convoy. After a while you'll know where to wait, Because nothing beats personal exp. :DL

"and besides a human brain is always smarter than that of an AI"

'Cept Bernard

[reignofdeath]

Yeah Im on my way to BE 29 now and theres a convoy route running through BE so Im going to wait around there and sink merchants to my delight. ive sunk 2 with one torp each already and ive got 10 left :yeah:

[JokerOfFate]

Little tip, if you're going after a convoy don't waste eels on lone merchants,
use the deck gun, although if they're armed just use an eel.

[Puster Bill]

The feel of having total control :DL, and besides a human brain is always smarter than that of an AI.

Other than that I love going on my gut feeling and manual it just so free :DL:DL:DL:DL:DL

I love that gut feeling, especially when I get set up on a "fast 90" approach on the HMS Illustrious, manage to penetrate her screen without being detected, and launch a full salvo of eels at about 900 yards, and instantly thereafter realize that I should have used 90 degrees *PORT* instead of 90 degrees *STARBOARD* for the AOB.

:damn::damn::damn::damn::damn:

[JokerOfFate]

:DLlol , thats why I don't use salvos

[Puster Bill]

:DLlol , thats why I don't use salvos

I wonder how often that happened in real life. What happened was that I got in front of the target track, and had to reverse because I ended up past the track. I then forgot to change the AOB. In the excitement, it's a *VERY* easy thing to miss.

[JokerOfFate]

Thats what happens to me all the time, lost in the moment :DL

[reignofdeath]

I love that gut feeling, especially when I get set up on a "fast 90" approach on the HMS Illustrious, manage to penetrate her screen without being detected, and launch a full salvo of eels at about 900 yards, and instantly thereafter realize that I should have used 90 degrees *PORT* instead of 90 degrees *STARBOARD* for the AOB.

:damn::damn::damn::damn::damn:

whats it matter in the TDC I mean either way its still 90 Degrees isnt it?? Im not familiar with manual since I use auto right now but Im just curious

[Pisces]

whats it matter in the TDC I mean either way its still 90 Degrees isnt it?? Im not familiar with manual since I use auto right now but Im just curiousIf you choose port when starboard is required, or vice versa, then the torpedo goes on a lag instead of a leading course. In otherwords, it will allways fall behind the target. You make the TDC think it is going the opposite direction.

[reignofdeath]

ahhhh got ya :up: I shall remember this when I have a patrols

[Pisces]

Damn you're quick!

[reignofdeath]

lol hey I try :woot:

[Puster Bill]

The worst part is that when I am figuring out the AOB I tend to stick my hands out and rotate my body a little. My wife always knows when I'm about to torpedo a ship because I do a little 'dance'.

[reignofdeath]

Lololol :)

[the.terrabyte.pirate]

Here's my nasty little intercept technique.

1) Pick your targets. I know that my type II has a max speed of 12 knots in fine weather under normal propulsion. Reaching the target has to be achievable. If it's too far away, traveling too fast, or in the wrong direction then it's a lost cause.

2) I start by plotting with the ruler a line from the contact in the exact direction that the contact update states. The contact hardly ever travels exactly along the direction stated (N, NW, ENE etc), but it's a good place to start.

3) Using the protractor I draw a circle with the center on the contact report. If the contact is slow, I'll draw it 6 km radius. If it's medium, 12 km. 6 km represents 6 knots. 12 km represents 12 knots. It's not accurate, but that's irrelevant.

4) Then I do exactly the same for the position of my boat, with a 10 km radius representing 10 knots. This then shows me that in the time it takes me to travel to the edge of the 10 km circle, my target should be approaching the edge of it's circle.

5) I then simply continue to expand the circles by the respective amounts. A slow target's circle would expand to a radius of 12 km, then 18km, then 24 km, while mine expands from 10 km to 20 km, then 30 km etc.

6) Eventually the edge of my circle with intersect with the course of the target. If the edge of my circle intercepts that point before the edge of their circle, it means that I will reach an approx intercept position ahead of them. If their circle has already past that point, it means I either need to either intercept further along it's path, or I need to increase my speed to be at that point earlier. Naturally if the target is traveling medium - fast, chances are that no matter how far along the path I plot an intercept, he'll always be there first. Lost cause.

7) If the intercept is good then navigate to the intercept point at the appropriate speed, submerge, and travel back along his path towards him.

Most of the time I'll pick him up on sonar, and will be in a prime position to attack.

Although the km radius of the circle represents the speed of the target in knots, it is simply a relative measure of distance over time, and not meant to predict an exact time of interception. It only ensures that I'll be there first.

[desirableroasted]

Here's my nasty little intercept technique.

1) Pick your targets. I know that my type II has a max speed of 12 knots in fine weather under normal propulsion. Reaching the target has to be achievable. If it's too far away, traveling too fast, or in the wrong direction then it's a lost cause.


Great post generally, but your first nugget is golden.

The classic beginner mistake is to tear around at flank speed looking for targets, then having to return to base with an empty tank and a full magazine.

In GWX, at the most fuel-efficient speed (8 knots), a VIIB has 14 weeks of fuel and 30K km range.... plenty of time and space to use 14 torpedoes effectively.

[reignofdeath]

After many times of doing it over and over again I finally started getting the interception stuff down in my head, so I think Im pretty good with interception now, 9 out of 10 timesI always make the intercept, the 10th is always becasue I fudge up on a mistake but thats expected.