Learning Manual Plotting and TDC

[GC1CEO]

I have embarked on learning how to work with 100 percent realism, however I am the kind of person who has to learn things in his way so after a few mission attempts and reading through a few manuals, I have to come to a few conclusions/theories and want some feedback on them to see if I'm getting the right ideas.

It seems like the best approach is to get the target's course and speed and not actually calculate the rest until I'm at a spot far ahead in the target's course where I intend to fire versus trying to gather AoB and all that at each initial observation where all I'm trying to determine if course and speed.

The easiest way to get an observation seems to be visually, I can't really determine range at this point with the hydrophone and obviously the sonar operator isn't about to give it to me. So I identify the target class and such, this part is pretty easy. Next I determine range through the stadimeter, I'm not sure how to do this accurately from a distance between of the waves but the difference in measurements i have gotten have only been different within a few hundred meters so its not neccesarily a big big deal. I really dont need the AoB as my intent in the end of all of this will be to make it so the AoB is 90 degrees when I fire. Speed is a bit tough, however I suppose I can guess-estimate with Slow being 6 knots, Medium being 10 knots and such for a merchant.

I take enough of these observations to know the course and speed, from this I know where the ship will be at any given point along its course at a given time. If my measurements are accurate then I don't really need to observe the target anymore, I figure out a parallel course and take it and get ahead of the target. If the target's course is 200, obviously a parallel course is also 200 and the course I want to hit AoB 90 Starboard will be 290 degrees. My ideal distance to target when I fire will be between 600-800 m but I'll settle for up to 1000-1200 m.

So I get to a point where I'm only 800ish m from the target's course, so it should be crossing directly in front of me. I got its speed (lets say 6 knots), its planned range at that point (800 m), AoB 90 starboard. I input all this manually into TDC, set my torpedoes (I figure either I or M and at F) and wait with periscope up, although in theory I guess I could use hydrophone on this. I merely need the current bearing to target, nothing else.

I'm not totally sure on the next bit of when to actually hit fire, my first guess is to fire when its at exactly 0 degrees but I think its gonna miss because it'll be hitting 0 in front of me by the time the target is say 5-10 degrees from me. I'm not sure on this part. But the rest makes a degree of sense to me.

Any feedback?

[Dantenoc]

Lots of feedback, but I'll stick to the most relevant issues.

1) Don't use the stadimeter, it's worthless except for extremely short ranges. Use the watch officer instead

2) Learn to use the 3:15 rule so that you can acurately read the targets speed from the marks on your nav-map.... or learn to tell the targets speed from the hydrophones. There is an excelent training mission for this, I'll look for the link later

3) Don't fire when your scope heading is zero, rather when the gyroangle on the torpedoes read 0.

With those three points you'll see a world of difference :yep:

[GC1CEO]

A bit of a point, can't exactly use my watch officer if I'm submerged and depending on the distance I dont want to surface because I'll be spotted which I really dont want to happen.

Yep already familar with 3:15, although I downloaded a nomograph and going to give that a bit of a try since different time frames might work better for me.

[don1reed]

Hello GC1CEO

you need to goto

http://www.paulwasserman.net/SHIII/

You also need to goto the top of the screen and do a search for, "greyrider". He has his finger on the hydrophone pulse...

and also listen to, Dantenoc. I was hoping he would show you his method of interception of single ships and convoys...all in good time, I guess.

cheers,

[Threadfin]

Here's the easy way. It works well, it works fast.

Find a ship and ID it with the recog manual.

Use the stadimeter by clicking the word range on the datapad to set the range.

Estimate the AoB and set the value by clicking AoB on the datapad.

Click the word speed on the datapad, and you will see a small clickable stopwatch icon. Click this icon and the timer will start. This determines the target's speed based on the accuracy of the range and AoB you set. Generally an accurate speed can be obtained with about a 10 second reading. I usually take several of these, and if each gives a like result I can be sure it's relatively accurate.

Once you'e hapy with the speed, range and AoB, click the checkmark on the datpad to enter the info in the TDC. Once you get the hang of it this method takes about 30 seconds at most, less in some cases. I've been using manual TDC for quite a while and average over 90% hit rate, a good percentage of my patrols are 100%. It's fast and easy to do it this way.

The key with this method is to be completely stopped, your boat should have no way, as the movement isn't factored into the reading, and since speed is measured by the apparent angular change of the target through the optic, any movement your boat has will affect the speed reading.

[Dantenoc]

and also listen to, Dantenoc. I was hoping he would show you his method of interception of single ships and convoys...all in good time, I guess.
cheers,

OK, you asked for it! :lol: ... here's a shameless plug for two of my posts:

http://subsim.com/phpBB/viewtopic.php?t=47980&highlight=clarens+revised

http://www.subsim.com/phpBB/viewtopic.php?t=48026

:up:

Also, most importantly, here's where you can download Greyrider's excelent info on how to determine speed by the sounds that you hear on the hydrophone

http://www.subsim.com/subsim_files/patches2005.html#sh3
(It's the "Sound trainer" listed after "AIL SKY MOD v2.0" and before "Sansal's Milk Cow Mod")

[Dantenoc]

A bit of a point, can't exactly use my watch officer if I'm submerged and depending on the distance I dont want to surface because I'll be spotted which I really dont want to happen

Ahhh.... you still think you're on a sub, right?

Change your paradigme. The U-boat is not a Submarine, it's a torpedoe boat with the added bonus of being able to "hide under the waves" when very special circumstances call for it. Some good reasons for not going underwater are:

* Your boat is faster on the surface
* Your boat is invisible to enemy ASDIC on the surface
* Your boat doesn't run out of air or battery power when on the surface
* The Watch officer can only work his rangefinding magic if you're on the surface
* The UZO is way superior to the attack scope, because it is mounted on a special stabilizing structure.

At the beginning of the war, when the U-boats could operate on the surface, they proved to be devastating to the allies. Later in the war, when things like allied radar and air cover forced the U-boats to function under water more and more, they became less efective, eventualy loosing the "Battle for the Atlantic"

Anyway, just stay farther than 5 kms in the daylight and 3 kms in the nightime and you wont be detected. You can even get away with getting closer sometimes, but there's no need to risk it. If you're like me and like to fire your torps from 400 mts (up close and personal) then just maneuver on the surface for an ideal shot position AND THEN submerge and wait for the enemy to cross your path... but by then you already have all the info for your targeting solution. :|\

Hope this helps somewhat

[redsolo]

If you need another way of finding the speed of the other boats, or just want to have fun (!?) while waiting for the ship to get into your sights; then you can use the "Sound Trainer" mod (downloaded at http://subsim.com/subsim_files/patches2005.html). Its not really a mod, but download the zip and read the document in it. It has a table of the most common ships and their "sound" at different speeds. So if you unsure of the speed, just get the RPMs and check the table, and voila you have the exact speed or from it you can determine what type of ship it could be.

Ship + RPM => Speed
Speed + RPM => type of ship

Its not necessary but some kind of fun :P

[don1reed]

A bit of a point, can't exactly use my watch officer if I'm submerged and depending on the distance I dont want to surface because I'll be spotted which I really dont want to happen

Ahhh.... you still think you're on a sub, right?

Change your paradigme. The U-boat is not a Submarine, it's a torpedoe boat with the added bonus of being able to "hide under the waves" when very special circumstances call for it. Some good reasons for not going underwater are:

* Your boat is faster on the surface
* Your boat is invisible to enemy ASDIC on the surface
* Your boat doesn't run out of air or battery power when on the surface
* The Watch officer can only work his rangefinding magic if you're on the surface
* The UZO is way superior to the attack scope, because it is mounted on a special stabilizing structure.

At the beginning of the war, when the U-boats could operate on the surface, they proved to be devastating to the allies. Later in the war, when things like allied radar and air cover forced the U-boats to function under water more and more, they became less efective, eventualy loosing the "Battle for the Atlantic"

Anyway, just stay farther than 5 kms in the daylight and 3 kms in the nightime and you wont be detected. You can even get away with getting closer sometimes, but there's no need to risk it. If you're like me and like to fire your torps from 400 mts (up close and personal) then just maneuver on the surface for an ideal shot position AND THEN submerge and wait for the enemy to cross your path... but by then you already have all the info for your targeting solution. :|\

Hope this helps somewhat


lol...in 1943, when their radar is in full swing....start thinking like a sub again, or as they say in NJ

Fugetaboutit.

[Dantenoc]

lol...in 1943, when their radar is in full swing....start thinking like a sub again, or as they say in NJ

Fugetaboutit.

Yeah I know... it's like a completely different game from there on :shifty: .... happy days are over :dead:

But it can still be a lot of fun :up:

[Tonnage_Ace]

If you're like me and like to fire your torps from 400 mts (up close and personal) then just maneuver on the surface for an ideal shot position AND THEN submerge and wait for the enemy to cross your path... but by then you already have all the info for your targeting solution.

Lol, at 400m you don't need a firing solution! :rotfl:

[Demonspawn]

If you're like me and like to fire your torps from 400 mts (up close and personal) then just maneuver on the surface for an ideal shot position AND THEN submerge and wait for the enemy to cross your path... but by then you already have all the info for your targeting solution.

Lol, at 400m you don't need a firing solution! :rotfl:

Considering once I fired at 450m and missed.....
it was my first 100% my own work shot (I didn't use the WE at all). I had him lined up perfect, knew his speed, and was at 90 AOB.

Except I entered I was 90 Port, not 90 Stb...... :huh: :damn: :damn: :damn:

[Dantenoc]

Considering once I fired at 450m and missed.....
it was my first 100% my own work shot (I didn't use the WE at all). I had him lined up perfect, knew his speed, and was at 90 AOB.

Except I entered I was 90 Port, not 90 Stb...... :huh: :damn: :damn: :damn:

I know... it's been known to happen :doh:

Anyway, the best "firing solution" is developed not for the torpedoe firing itself, but for the U-boat positioning. Getting yourself into a no-miss situation is a firing solution in itself. However, even at those extremely close ranges you still need to have a very good firing solution if you want to target a specific part of the ship for a one shot kill... in a sense, hitting a ship with three torp to sink it is just as bad as one miss and two hits for a sink. :hmm:

[Demonspawn]

I usually go for the "crack the hull" shot, around 0.5-0.75m under the draft, magnetic detection, and around the center of the boat. Reciently, I came across a C2 and did this to him, except I stupidly forgot to open the torpedo door first, and ended up under the back quarter of the boat. What happened next supprised and annoyed me.

The C2 laid there, fully half awash, at 0Kts for the next two hours. (I shoulda taken a screenshot.) I finally surfaced and backed up to around 1km range so I could fire my deck gun under the bow waterline. Around 35 shots of HE later, he was starting to list heavily so I held fire until he eventually capsized... a half an hour later.

One tough cargo ship!! :huh:

I've got two questions I'd like to present:

Should I be running my torps deeper? I've heard 1m to 1.5m is the best for cracking the hull in two, but I'm afraid of not having the torp detect the boat (speaking clam waters.. in rough, I always aim for engines/fuel).

Is HE or AP deck gun ammo better for sinking a disabled cargo? I tend to use my HE first, in fact I usually sink any lone cargo smaller than a C2 using only the deck gun if I'm outside of air coverage.

TIA

[Heibges]

Remember, your firing point is before the AoB is 90°.

With 5° or 10° of lead, the AoB will the 80° or 85° pt or stb

[Demonspawn]

Remember, your firing point is before the AoB is 90°.

With 5° or 10° of lead, the AoB will the 80° or 85° pt or stb

There's a way around that slight problem that you can use if you posistion your u-boat very well (90 AOB). It requries a lot of marks on the map, but it's worth it. You line up your shot at 90, and then move your periscope up at 360 or 180 (bow or aft shot), then you AOB calculator on the spreadsheet and set it to 90 (sbd or port) and enter it into the TDC. I adjust the range and speed manually, and then set it to automatic calculation. For example, on the shot I'm lineing up as I type, my 000 gyroagle shot on a 9Knt target is actually at 345 (est 600m range). This thing is wonderful :)

P.S. don't put the periscope up all the way, just barely over the water, helps with the detection factor a lot.

Edit: and it was all for naught. I had this heavy cargo lined up perfectly, and around bearing 310 I made out the flag.... Norwegan! If only I could follow him for 2 months I could sink him!!

[Heibges]

AoB 090 is at bearing 000 whether pt or stb. Even approaching at a perpendicular attack angle (not to be confused with AoB 90°), I find I have more success by firing with a 10° or 20° lead.

Before Black May but depending on the escort makeup, may times you can determine speed using the Matching Speed method. The beauty of this the Speed is determined long before you even get in attack position.

Take this time to also determine target course. Overhaul using the dogleg course, and get on a perpendicular attack course.

If you are approaching the target perpendiculary, you will notice a relationship between AoB and Bearing.

For example:

A ship is crossing your path from right to left, and you are on a perpendicular course to the course of the target.

So we know the AoB will be PT because we will be firing at the PT side of the target.

Now when the bearing is 45° you will notice that the AoB is 45° pt. You will also notice that as the bearing moves towards 000°, the AoB moves towards 090°. (If the ship was crossing your path from left to right the AoB would move towards 090° as the bearing moved from 270° towards 000°.)

So if we have the good perpendicular attack course, we know we want to lead the target, so if we are going to fire at bearing 010°, we know the AoB will be 080°pt.

And we figured out the speed by matching our speed on the surface at the edge of visibility. If you receive a contact report on a convoy, the speed is generally within a knot or 2 of the actual convoy speed.

Finally you need range. I use the MILS method, although I'm not sure if the scale on the periscope is actually a MILS scale. Basically, if you measure the length of a ship with the scale on the periscope, it will give you the range if you know the width at a given range.

For example, a C2 Cargo ship is 6 MILS long at 1200m.
A C2 Cargo ship is 12 MILS long at 600m.
A C3 Cargo is 7 MILS long at 1200m and 14 MILS long at 600m.
So by measuring the length of the ship it instantly tells me its range.
The close you are to bearing 000 and AoB 090°, the more accurate the measurement will be. Otherwise you will have to estimate a little bit.

I do not use the notepad, but enter the solution into the TDC manually.