Intercepting

[ddiplock]

With it being Mid 1943 now in my campaign, and Allied forces using Radar in earnest now, its very difficult to move into an attack position on the surface without being detected. The problem therein also lies in the ability to know the course of the ships in question, in order to get into an attack position.

Is there a way, when your forced to dive after detecting radar signals, that you can use the hydrophones to plot the course of the target if its the case of a convoy or a task force who's radar you've detected?

I've come across several task forces and convoys, but i've missed out on each because I don't know which direction they are heading while i'm submerged, and can't plot an intercept course. Why just earlier, I thought I was heading in the right direction to intercept a Task Force after picking up their radar, only to discover I was infact heading the wrong way.

Any help guys?

Cheers :D

[UnderseaLcpl]

I assume you have "no map contacts" on, if not you can always plot the limits of the bearing lines to get a good idea.
Personally, when trying to play with the contacts off, I find it best to use the follow contact option under the hydrophone operator's menu. Your goal should be to get a steady 90 degree bearing.
It's of course, much harder then it sounds (no pun intended)
Take the hydrophones and listen for a minute to see if the contact bears port or starboard, alternatively you can have the operator follow nearest contact.
Take off at flank speed in the general direction ahead of their bearing.
Continue to monitor the bearing reports and see if they are getting closer to perpendicular with you. If they are, you're in good shape for an intercept.
If not try altering course farther away to a maximum of 90 degrees away from the bearing. If they still move towards zero you're not going to catch them. Also, leave the periscope up and check it in the bearing direction from time to time.
I use this technique in conjunction with TC but the process can still be tedious.

As far as convoys go your best bet is acting on reports from B-Dienst as they give a general bearing, a map location, and best of all, a speed.

One more thing before I wrap this up, you can always torpedo the escorts, radar be damned. It eliminates you needing to find them....
I'm sure some have seen my responses in various posts for my DD killing technique, if anyone would be interested in a long post with a full explanation please say so and I will make one.

Hope this helps a little.....

[Letum]

I think it is very important to get at least two visual sightings of the convoy a few
minutes apart, longer apart if possible. The longer the better. Even if it means
exposing your self to detection. Or one good AOB reading, but this is harder to get
than two position plots.

Radar can sometimes be used to get the two accurate position plots, but will also
expose you.

[ddiplock]

One thing I wonder about is WHEN can they actually detect you with their radar. The way things seem with my radar warning antennae, is that I can detect their emissions, but maybe i'm still outside the range of their radar, so, I end up knowing roughly where they are, before they know I'm near.

I dive pretty quickly after I detect them, and they never take evasive action, this leads me to conclude they haven't detected me, and thus you could further conclude, it can give you a little bit if leeway on the surface to use the diesals to get into position.

The only problem is, you don't know when they have detected you, and could end up ruining the whole thing if you stray into the range of their radar while trying to get into position.

[richardphat]

In this case try to get snorkel as soon as possible you can catch them up if they are a bit far!And usually a periscope can zoom up to 6x so i guess you would be able to see approximately 3 or 4 km. DD cant detect with their sonar because you are too far from them

[ddiplock]

In this case try to get snorkel as soon as possible you can catch them up if they are a bit far!And usually a periscope can zoom up to 6x so i guess you would be able to see approximately 3 or 4 km. DD cant detect with their sonar because you are too far from them

Yeah that's true. But, its also a bit unrealistic. I do know that in SH3, you can have a Schnorkel and run at flank speed when its up, but in real life, a Uboat was limited to no more than 6 knots with the Shcnorcel extended, else it would break off. lol :up:

[rifleman13]

I just saw a convoy course SSW just west of the Bay of Biscay.:arrgh!:

When I come to intercept it, I can't see it. When I ordered the crash dive to 70m to check out on the hydrophones, nothing.:damn:

What's going on! Are they steaming straight or, just like in real life, zigzagging!:damn:

Thnx for any replies!:up:

[Brag]

In GWX convoys change course frequently.

[difool2]

My one experience with being surfaced and the DD's radar detecting me indicated a range of about 16km (at which point I got the message "Enemy is engaging us sir!" Of course by the time he steamed to where I was I was already on a submerged intercept course with his convoy). Sea state may affect that.

[Pisces]

To get a target's course based on (hydro) 'bearings only' look at the following from a guy named Redwine. Because of his language (I think he's from argentina) it may be difficult to follow, but the formula works.

http://rotteufel.iespana.es/htdc_tutorial/manualtdc_009.htm

I found a sliderule ages ago that works by the same math but handles it in an easy way. Take 3 bearings, with equal time intervals (think long, not 3m15s, bearings move sloooowwww), line up the difference between the bearings of time1 and time3 with time1 and time2 and read off the AOB of the target at time1. BUT this is ONLY the true AOB if you are stationary. If you move (with significant speeds) the angle is NOT the AOB but skewed so-to-say by relative motion. So then it should be called 'Angle On Relative Motion'. Which is very difficult to correct for. (needs two sets of these 3 bearings while the sub is on 2 different courses or speeds and some vector-math for desert) Also, accuracy is very much hampered by the fact that Silenthunter (series... the slideruler was made back in the sh1 days I think) do not supply fine bearings (like with tenths of a degree). Bearings are all given in round degrees which makes the outcome very fuzzy/unprecise. Try it adding halve a degree either side on both bearing differences. You'll see what I mean. Also, you can't tell how fast it is, or the range it is at. But target course is a whole lot allready. You just need the time to wait for the bearing to move enough.

Here's a webcam image showing my poor attempt to make this thing (bad quality):
http://ricojansen.nl/image/3bearingAOB_slideruler.jpg
Let's say I took 3 bearings with 2 equal time intervals inbetween with my hydrophone (but periscope or whatever works just the same) B1=087, B2=081, B3=072, the bearingdifferences (6 and 15 degrees) result in a Target AOB at time of bearing 1 being 26 degrees. Since the target was moving from your rightside to your leftside (passing in front of you) he was 'showing' his left/port bow. Draw the angles out on paper and you can see the target's course.

I don't know who made it so hopefully they won't mind I uploaded it to my homepage, for availability sake. The .zip file contains a .htm file with information on the assembly and use of the tool by the original maker. The drawing for the tool can be print from a (autocad vector format) .dwg file, or an ordinary .gif image.

http://ricojansen.nl/downloads/gizmos.zip

[Pisces]

I updated the first link above. It was sending you to the wrong place on his site. This guy's site is sooo confusing!!! Too bad, because there's great technical knowledge in it.

[gAiNiAc]

One more thing before I wrap this up, you can always torpedo the escorts, radar be damned. It eliminates you needing to find them....
I'm sure some have seen my responses in various posts for my DD killing technique, if anyone would be interested in a long post with a full explanation please say so and I will make one.

....

I'm always interested in DD killing techniques............

I'm pretty good but I still find myself crash diving and evading radically at times when I don't nail them..........

Martin

[XLjedi]

If you don't mind using MoBo, it has a TMA tool for converting hydro bearings to target true course...

You can see how it works here:
http://www.subsim.com/radioroom/showthread.php?t=121929

Just review the "Advanced TMA Help" link. If you're stationary it's pretty easy, if you're moving it's a little trickier. :ping:

[kylania]

Here's an old picture I found on these forums years ago, still works pretty well for me:

http://www.kylania.com/sh3/Intercept_Plotting.png

[XLjedi]

Here's an old picture I found on these forums years ago, still works pretty well for me:

http://www.kylania.com/sh3/Intercept_Plotting.png

Yes... that works well if you already know the target TC (the black line).

I think OP is looking for ways to determine true course without a map prompt that says "East".

[Robert Fulton]

To get a target's course based on (hydro) 'bearings only' look at the following from a guy named Redwine. Because of his language (I think he's from argentina) it may be difficult to follow, but the formula works.

http://rotteufel.iespana.es/htdc_tutorial/manualtdc_009.htm

...

Thanks. This is very useful. Despite knowing hardly any Spanish, I was able to work my way through this with a little help from a dictionary and also found this site with Spanish nautical terms: http://bahiaredonda.com/dictionary/dictionary.php.

Given how important accurate bearing readings are to this calculation, who has tips for accomplishing this? I find that if a target is at between 20km and 30km, I must go to the hydorphone myself. And so far my skill level is not all that precise (maybe I need better headphones :)).

As an aside, this forum has immensely increased my enjoyment of SH3. I am a novice still in my 1st career with the stock game.

[Pisces]

Longer time intervals inbetween taking the bearings makes the AOB error reduce alot. But this has the disadvantage of possibly putting you well behind his 90 AOB when you are done. And you also don't know how long he is going to stay in your hydrophone range.

So it's best to start with the smallest amount of bearing drift for the initial interval (for the tool I provide a download link to: take a time until b2-b1 becomes 5 degrees) to have a rough estimate on AOB. Compute how many degrees this rough AOB can grow until it reaches 90 degrees (assuming it is not allready past it). Take that as the bearing change for 2 intervals (B3-B1), and look how many degrees that would be for the 1st one interval (B2-B1), leaving the marker set on the rough AOB. Deduct one or two degrees for good measure from this (B2-B1). And repeat the 3 bearing method by waiting until the bearing has drifted this new (B2-B1) since the very first bearing taken.

Apart from that you can get a slightly better resolution out of your hydrophone. If you listen to the sides where the sounds are barely audible, and average those, you get the bearing to the target. This works alot better than finding the maximum volume. If one of those sides is an even number and the other is an odd number the true bearing is somewhere close to xxx.5. Allways take that halve decimal when you can get it!!!

...(maybe I need better headphones :)) The hydro station has a volume knob built-in aswell. ;)


Thirdly, make sure your rudder is amidships, even if you think you have no speed! You don't want to have very slow turning screw up the bearings.

[Robert Fulton]

...
Apart from that you can get a slightly better resolution out of your hydrophone. If you listen to the sides where the sounds are barely audible, and average those, you get the bearing to the target. This works alot better than finding the maximum volume. If one of those sides is an even number and the other is an odd number the true bearing is somewhere close to xxx.5. Allways take that halve decimal when you can get it!!!

...(maybe I need better headphones :)) The hydro station has a volume knob built-in aswell. ;)

...

Pisces, you provide a treasure trove of valuable information. I had tried the averaging from the outer limits method, but only with modest success. My difficulty is picking up on the precise locations where I lose all contact. I had looked for a volume knob at the hydro station, but did not find it. I am now eager to do so. Is it there in the stock version? (I am away from home for a while, and cannot recheck for myself.)

[Weiss Pinguin]

Yup, there should be a knob on the lower-right corner of the hydrophone station. Click on the top of it to increase the ambient volume.

[FIREWALL]

Three things I've found you have to get good at to really get the gut tightening immersion from this sim.

Manual targeting, the hydrophones and plotting courses and not necessarily in that order. :D

When you master those your a Kaluen. :arrgh!:

Then the bottom line is tonnage.:yep:

[Robert Fulton]

Thanks, guys. I shall look for that volume control upon getting home before even taking my hat off.

On the way to immersion, too. I have course plotting down pretty well; I am working on the hydrophone; manual targeting is next.

I already get pleasure from the increased contacts I am getting with my current hydrophone skill. The last two patrols I have been taking it down to 25 meters; all stop; listen for a couple of 360s; then I turn 45 degress at ahead 1/3 and repeat to pick up anything in the blind spots. I estimate I am getting several contacts per patrol that I had been missing by relying solely on my highly qualified and decorated radioman. After all, the area of a 30km circle is more than double that of a 20km circle.

[FIREWALL]

Thanks, guys. I shall look for that volume control upon getting home before even taking my hat off.

On the way to immersion, too. I have course plotting down pretty well; I am working on the hydrophone; manual targeting is next.

I already get pleasure from the increased contacts I am getting with my current hydrophone skill. The last two patrols I have been taking it down to 25 meters; all stop; listen for a couple of 360s; then I turn 45 degress at ahead 1/3 and repeat to pick up anything in the blind spots. I estimate I am getting several contacts per patrol that I had been missing by relying solely on my highly qualified and decorated radioman. After all, the area of a 30km circle is more than double that of a 20km circle.

Doesn't sound like you need any help. :D :up:

[UberTorpedo]

Robert Fulton

Here's some other hydrophone hunting tutorials you might find interesting.:know:

http://forums.ubi.com/eve/forums/a/tpc/f/857101043/m/7821098535/p/1
and
http://www.subsim.com/radioroom/showthread.php?t=110619

The video (U42HydroHunt.exe) for both posts has also been uploaded to my Filefront. See link under my sig:)

cheers

[Sandman_28054]

With it being Mid 1943 now in my campaign, and Allied forces using Radar in earnest now, its very difficult to move into an attack position on the surface without being detected. The problem therein also lies in the ability to know the course of the ships in question, in order to get into an attack position.

Is there a way, when your forced to dive after detecting radar signals, that you can use the hydrophones to plot the course of the target if its the case of a convoy or a task force who's radar you've detected?

I've come across several task forces and convoys, but i've missed out on each because I don't know which direction they are heading while i'm submerged, and can't plot an intercept course. Why just earlier, I thought I was heading in the right direction to intercept a Task Force after picking up their radar, only to discover I was infact heading the wrong way.

Any help guys?

Cheers :D

Perhaps its just me, but what I have done in those situations is to dive as soon as I get the warning of "detecting radar."

I dive to periscope depth, and raise my periscope. Using the "pencil" I will "mark" their position. As somebody said, you need at least two visual observations. When you have these two marks, its easy to plot their course and an intercept.

[FIREWALL]

A simple way is get them on your hydro and turn into them till your at 0 degrees and see if they go port or starboard or right at ya.:D

[Pisces]

Robert Fulton

Here's some other hydrophone hunting tutorials you might find interesting.:know:

http://forums.ubi.com/eve/forums/a/tpc/f/857101043/m/7821098535/p/1
and
http://www.subsim.com/radioroom/showthread.php?t=110619

The video (U42HydroHunt.exe) for both posts has also been uploaded to my Filefront. See link under my sig:)

cheersIndeed, the 2nd image in the 2nd link... or to be less confusing ... this one:

http://img102.imageshack.us/img102/7330/navmapwoenglishoi3.jpg

... shows what is missing with the 3-bearing sliderule post (figuring out range and speed). Project an imaginary future 4th bearing line on the map (by drawing the target track at an arbitrary range, and copying the distance between bearing intersections with a circle) and sprinting away from the listening location for the duration of the interval as fast as possible. A real 4th hydrophone bearingline (the 5th in the image) taken from the new position should intersect the imaginary 4th bearing at the real location of the target at that time. From that also speed can be figure out. (once the target track is re-drawn through the 4th bearing position fix.)

I really should be making a complete walkthrough of this oneday. Ugh, so often I promised to do.

[XLjedi]

Robert Fulton

Here's some other hydrophone hunting tutorials you might find interesting.:know:

http://forums.ubi.com/eve/forums/a/tpc/f/857101043/m/7821098535/p/1
and
http://www.subsim.com/radioroom/showthread.php?t=110619

The video (U42HydroHunt.exe) for both posts has also been uploaded to my Filefront. See link under my sig:)

cheersIndeed, the 2nd image in the 2nd link... or to be less confusing ... this one:

http://img102.imageshack.us/img102/7330/navmapwoenglishoi3.jpg

... shows what is missing with the 3-bearing sliderule post (figuring out range and speed). Project an imaginary future 4th bearing line on the map (by drawing the target track at an arbitrary range, and copying the distance between bearing intersections with a circle) and sprinting away from the listening location for the duration of the interval as fast as possible. A real 4th hydrophone bearingline (the 5th in the image) taken from the new position should intersect the imaginary 4th bearing at the real location of the target at that time. From that also speed can be figure out. (once the target track is re-drawn through the 4th bearing position fix.)

I really should be making a complete walkthrough of this oneday. Ugh, so often I promised to do.

This picture represents exactly what the TMA tool in MoBo was built to do... In fact, you can also add vectors to negate your own subs movement to get an accurate true course if taking the bearings while moving.

Anyone ever try it?

[Robert Fulton]

Ubertorp, Pisces, Firewall: You guys are awesome. This forum is awesome.

Thanks to Mittelwaechter, too. I am sooooo eager to get back to my hydrophones and become proficient with these methods and tools (currently 2,100 km away from my boat ;) ).