Failing to detonate torpedo

[GoldenRivet]

Originally Posted by aluc24

Out of pure interest, why is that, exactly, this little effect? Because theoretically, range shouldn't matter at all, at least to my knowledge of trigonometry. Does it have something to do with torpedo acceleration to it's cruise speed after launch? Or maybe it's due to torpedo slowing down due to lesser charge in it's batteries? (not sure it's simulated)

The trig you refer to is an equation for a perfect triangle... Bearing being side a, target path being side b and torpedo path being side c. The firing solution for our torpedoes does form a triangle however the triangle is not a perfect triangle... one corner of the triangle is an arc

this is because the torpedo has to accelerate out of the tube and then make a turn of anywhere from 0° to +/- 150°thus the base of the triangle is not an angle... it is a curve, so there is a bit more to it than a triangular equation

Originally Posted by aluc24

P.S. GoldenRivet, you said you acquired all necessary info for attack in time it took for target to move 3 degrees. I wonder how. You said that range is estimated visually. Stadimeter, or just eye-ball guess?
Speed - did you use hydrophone to calculate propeller revolutions, or again, educated guess?
AOB is most interesting. How did you go about that? I always have a problem estimating AOB without drawing a lot of stuff on the map, which takes time - so I assume you have some faster way to do it?

Please, share your methods

I used the T.L.A.R. method

"That Looks About Right"

It was a quick judgement call that comes from playing SH3 on a near daily basis in some form or another from March of 2005 through to the present day.

I eyeballed the range, as players get more experienced they become used to seeing ships at various ranges... i just did a quick estimate of 1,000 meters and dialed in 1100 into the range dial. I was apparently off by a few hundred meters as the impact came about 8 seconds before the clock said it was due

Speed i assumed about 5-6 knots. When a hydrophone operator reports "moving slow" it is my experience that this is anywhere from about 1-6 knots. if he reports medium speed this is generally in the ballpark of 6-11 knots, moving fast is anywhere upwards from 11+ knots just in my observations. Looking through the scope, i saw the ship cutting a pretty decent wake on its bow, so i assumed he was at the higher end of what the game considers "slow" and so I dialed in 5 knots

As for AOB, i used to draw a lot of stuff on the map, but eventually graduated up to turning map updates off, i then would take range and bearing observations and use an actual pencil, ruler, paper and protractor to plot the ship on paper to arrive at the requisite numbers for the firing solution. While it offered a neat challenge, it was time consuming to do it this way. I eventually stopped doing that with enough experience to estimate the AOB visually with about a +/- 5°-10° margin of error and when you are firing inside a range of 1KM the margin of error there is pretty loose. On a long range shot at a higher value target like 3KM range at a massive battleship or a huge liner i will just whip out a paper and do it old school

so yes... i more or less brought up the TDC... plugged in the numbers that looked about right to me and fired the shots.

from the time i looked in the scope at the target to the time i ordered the shots fired was perhaps 10-15 seconds. tops

[GoldenRivet]

Addendum to the above post


I would turn map contacts ON if i were you and get some practice with the TDC.

there are two things folks have trouble with when using the TDC

solving for speed

solving for AOB

fortunately both are actually ridiculously easy thats why the Kriegsmarine put the TDC in there so any 20 year old German kid could set it up and sink a ship

Solving for speed:

1. come to a dead stop as close to 0-1 knots as you can

2. find your target in the scope, put the vertical cross hair slightly in front of the ship

3. when the ship's bow moving through the view first touches the vertical cross hair start your timer, stopwatch, wristwatch whatever

4. without moving the scope, keep looking. when the stern of the ship passes the cross hair just stop the timer.

5. look at the ship in the recognition manual (hopefully you took a moment to ID her) you will see measurements - you need to know the length of the ship

6. so lets assume a couple of things. the ship is 180 meters long, and it took 34 seconds to cross your scope's cross hair.

take 180 and divide by 34

this gives you a result of 5.29

convert that to knots by multiplying 5.29 x 1.95 (a set number which never changes)

5.29x1.95= 10.315 knots (round it to 10 even)

speed is 10 knots set that into the TDC and you're done with speed

just be sure and keep your scope low in the water in broad daylight good weather attacks to keep it from being spotted. Lower it near completely when you are not looking through it

----------

AOB is also super easy when you have map contacts enabled, i am a supported of map contact updates for the sole purpose that you are a 3 dimensional being interacting with a 2 dimensional simulated world that wants to be 3 dimensional but cant... a lot of situational awareness is lost in the visual translation and map contacts turned on really helps to make up for that.

here is my AOB tutorial video on youtube that you can watch when you have 3 and a half minutes to spare

[BigWalleye]

Originally Posted by aluc24

You said that range is estimated visually. Stadimeter, or just eye-ball guess?
Speed - did you use hydrophone to calculate propeller revolutions, or again, educated guess?
AOB is most interesting. How did you go about that? I always have a problem estimating AOB without drawing a lot of stuff on the map, which takes time - so I assume you have some faster way to do it?

Please, share your methods

Here are two PDFs which describe methods for accurately determining range, AOB, and speed using the graticles found in actual WW2-vintage periscope optics.

German Optics, by Hitman, is found in the documentation section of the Hitman’s Optics mod. You can download it here: http://www.subsim.com/radioroom/down...o=file&id=1519

UJadg Tools, by joe grundman, is found in the documentation for the hsGUI mod. Download it here: http://www.subsim.com/radioroom/down...o=file&id=1648

Both links are currently active.

Hitman’s work is a unique, well-researched and documented description of the optical systems actually installed in Uboats during the war. He uses contemporary sources and personal examination of surviving periscopes from WW2 Uboats. His conclusions are sometimes ignored, but I have never seen them disputed.

joe grundman’s work provides step-by-step instructions for calculating range, AOB, and speed using graticles and either the AOB ring or the angriffsscheibe, tools which were actually available on WW2 Uboats.

In my experience, the use of graticles for angle measurement is at least as accurate as the stadimeter. And it requires no apriori positive ID of the target, although target ID can ensure a more trustworthy result. (Historically, target identification was the work of an identification party, not the Approach Officer. He merely called out descriptive features to the ID party, who looked through the book. According to first-person accounts, a positive identification of the target sometimes wasn’t made until well after a successful attack.)

These methods use tools similar to those which were present on actual Uboats. Operationally, they are neither more nor less historically appropriate than stadimeters and computer-generated speed estimates, because the Approach Officer did not do all the calculations himself. How you prefer to simulate the working of the approach party (8-10 officers and senior ratings, each with specific responsibilities) is a matter of your personal taste. AFAIK, there is no way to accurately simulate the tasks of the Approach Officer with SH3 and any combination of mods. (Or with SH4 or SH5 either.)

That said, SH3 is still, IMO, the best and most immersive sub sim ever published.

[aluc24]

"That Looks About Right"

from the time i looked in the scope at the target to the time i ordered the shots fired was perhaps 10-15 seconds. tops

Well that is pretty amazing. I guess there is no substitute for experience! I wouldn't dare relying on TLAR with so little experience I have, and so few torpedoes (a few misses, and I can go home with no tonnage sunk), but I'll always compare gut feeling with actual numbers to learn!

About your solving for speed method - it seems very handy, however, I believe it is perfectly accurate only when AOB is 90 degrees, right? And if AOB is 45 degrees, I should divide the final speed by 2, correct? Correct me if I'm wrong, but I just thought, if target is approaching with AOB like 15 degrees, it will take a lot of time for bow and stern to pass the crosshair...

AOB is also super easy when you have map contacts enabled, i am a supported of map contact updates for the sole purpose that you are a 3 dimensional being interacting with a 2 dimensional simulated world that wants to be 3 dimensional but cant... a lot of situational awareness is lost in the visual translation and map contacts turned on really helps to make up for that.

I have played with map contacts for some time, however, I found it way too easy... It makes advanced plotting techniques redundant. Two observations from periscope, and you basically know everything you need... What you say about dimensional differences is true, but I somehow feel that second case would still be more realistic... And more challenging.

For now, I'm learning to determine target speed and course solely with hydrophone. I can get decent results while being stationary, but moving 4-bearing method is still over my head.
And for actual attacks, I still rely on watch officer's range estimations. That won't be of much use later in the war, when I encounter convoys, so I'm working on hydrophone interception methods...

Your tips and techniques are very interesting and useful. Thank you. The tutorial is neat. Nice choice of music By the way, what is magical about 55 degree AOB? Why did you chose it, why not go with 90 degrees, since it would only require waiting a few minutes?

[GoldenRivet]

Originally Posted by aluc24

About your solving for speed method - it seems very handy, however, I believe it is perfectly accurate only when AOB is 90 degrees, right? And if AOB is 45 degrees, I should divide the final speed by 2, correct? Correct me if I'm wrong, but I just thought, if target is approaching with AOB like 15 degrees, it will take a lot of time for bow and stern to pass the crosshair...

The method works for virtually any angle on bow from about 30-120°

no further division needed.

Another method i used was to place a protractor at the bottom of a sheet of paper, trace the arc and mark the bearings in 10 degree angles with tick marks for 5 degrees from 270 through to 0 to 90.

In the game i would ID the ship, take 3 range estimations through the stadimeter and average them.

I would then use a pencil and ruler (assuming each 1/4 inch on the ruler to be 100 meters) abd u would draw the bearing line to the estimated range on paper.

I would then start my timer and wait about 2 minutes and repeat the process with updated information.

finally i could use the ruler to estimate how far the ship traveled by measuring the distance between observation point 1 and observation point 2 and mathematically determine the speed with the given distance and time.

however the time divided by ship length x 1.95 works for any reasonable firing angle

Originally Posted by aluc24

what is magical about 55 degree AOB? Why did you chose it, why not go with 90 degrees, since it would only require waiting a few minutes?

because 55 degrees was the AOB at the time of the observation and it allowed me to engage the target immediately without waiting. The torpedo automatically knows which way and how far to turn in order to steer itself to the target as close to a 90° impact as possible without you having to be close.

in a convoy situation when you want to send torpedoes at multiple ships, once you determine the AOB for each ship it is a matter of aiming at one, setting aob, firing and aiming at the other setting the new aob and firing. with practice, there is no reason you couldn't engage 5 targets with 5 torpedoes in a span of 15-20 seconds.

You could engage 3-5 targets and dive away before the fish ever hit without having to wait for each individual ship to reach 90° because after the first impact they are going to begin zig-zagging and the liklihood of subsequent misses increases dramatically - if you time it right by aiming at the furthest ship first, updating AOB and shooting, then aiming at the next closest ship, updating AOB and firing and repeating this process for subsequently closer ships... in theory you could hit all the targets at roughly the same time - or at least within the same 5-10 second window.

the advantage to not having to wait for each target to hit 90 degrees is that you can be 3 KM away from the convoy and in deep water before the first hits ever strike, and when they do... its very hard for escorts to find you, a skill that WILL become vital as the war progresses

[aluc24]

These are also interesting methods, thank you for sharing. By the way, why didn't you plot it all in SH3 map? It seems more handy than paper and pencil... Although I don't know about accuracy.

By the way, off-topic question: is there any way to fast-scroll through Ship Recognition Manual? Sometimes I know which page I should be looking at, but it takes a lot of time to mouse-click arrow button on the Manual to get to it. Is there a keyboard shortcut, or something? My mouse hurts from all that clicking...

[GoldenRivet]

Originally Posted by aluc24

These are also interesting methods, thank you for sharing. By the way, why didn't you plot it all in SH3 map? It seems more handy than paper and pencil... Although I don't know about accuracy.

way more handy than a pencil and paper, but the ruler tool in SH3 is not super accurate. Which is why i used paper

Originally Posted by aluc24

By the way, off-topic question: is there any way to fast-scroll through Ship Recognition Manual? Sometimes I know which page I should be looking at, but it takes a lot of time to mouse-click arrow button on the Manual to get to it. Is there a keyboard shortcut, or something? My mouse hurts from all that clicking...

as for this... click faster is the only way i know to do it.

just think of back in the day... they had several recognition manuals to search through

[aluc24]

Well, I see. Thank you very much for your help and support. It was fantastic I just sank a target in very complicated conditions with Type IIB: a small freighter (2229 tons), running at 9 knots. Conditions - night, severe storm, 15m/s wind, fog, rain, visibility around 800m. The target got away from me before I could intercept it on perpendicular, so I ran up right behind him, caught up to 400m, and sent a magnetic torpedo at 7,5m depth towards his propeller. All done with TDC, with range, speed and AOB known. Torpedo passed the propeller, ran along the hull a bit, and broke the bloody Brit in half. Only after explosion I could finally find out what kind of ship that was (my torpedo depth was a lucky guess). Believe me, conditions were horrible, I had to come up to 150m to recognize the bastard.

Such a satisfaction. Thanks again

[GoldenRivet]

As you get more practice, it will become more and more second nature and more and more satisfying.

I just started a new career in August '39

It is now September 8th, deck gunned two small merchants and plodded around with some dolphins for a bit, starting the return voyage tomorrow due to 50% fuel reserve.

On the way back to Wilhelmshaven I'll lurk down the eastern coastal waters of Great Britain

[aluc24]

Nice! I just flak-gunned (guess I won't shoot aircraft anyway) a Granvile-type freighter, 4707 tons. Total of 11758 tons sunk with this Type IIB, and still two torpedoes left.

By the way, while still on Type IIB, is it worth spending renown for better crew, or should I just save up for upcoming VII?

[aluc24]

Well, patrol has come to an end.

Here are the results:



That is total of 16466 tons. Just third patrol, in "training purpose" Type IIB. 5 torpedoes, 5 ships sunk. From clear skies to hurricane storm. Not bad for starters, huh?

In other words, I am indebted to you, man. Thank you for invaluable advice you gave me.

[GoldenRivet]

Originally Posted by aluc24

Nice! I just flak-gunned (guess I won't shoot aircraft anyway) a Granvile-type freighter, 4707 tons. Total of 11758 tons sunk with this Type IIB, and still two torpedoes left.

By the way, while still on Type IIB, is it worth spending renown for better crew, or should I just save up for upcoming VII?

save up

You are for sure going to want to venture out into the western approaches... not an easy task with a type II boat