A hello and some general questions about torpedoes and deck guns.

[Ovedius]

Hi, hello!

Ohoi, mateys?
...sorry.


In all honesty I am posting to raise my daily download limit.
But it is a nice opportunity for a slight introduction of myself and ask some questions about torpedo usage that have been tickling my curiosity bone.

Onwards!
I have recently been stricken by an insatiable apetite for Silent Hunter 4 and 3.
Though I am absolute rubbish at both, I just can't stop myself from trying again after my umpteenth manual torpedo strike goes everywhere but where I was aming.
-or after accidentally becoming a war criminal and a rogue after sinking merchant ships before open hostilites had been sanctioned by central command ...I didn't mean to, honestly!


So if one of you seasoned, salty submarine aces out there could answer some torpedo questions for me I would greatly appreciate it.
-the following questions are mostly related to Silent Hunter 4.


First, what is the purpose of adjusting torpedo depth?


What is the purpose of tampering with torpedo speed?
-why shouldn't I just set it to MAXIMUM speed?


Should I generally always aim for the sealine when trying to sink ships with my deck gun?


Am I right in assuming that AP shells are for warships and HE shells are for merchants?



Any input is greatly appreciated
-please excuse any English typos or grammtical oddities, I'm Norwegian.

[doulos05]

Originally Posted by Ovedius

Hi, hello!

Ohoi, mateys?
...sorry.


In all honesty I am posting to raise my daily download limit.
But it is a nice opportunity for a slight introduction of myself and ask some questions about torpedo usage that have been tickling my curiosity bone.

Onwards!
I have recently been stricken by an insatiable apetite for Silent Hunter 4 and 3.
Though I am absolute rubbish at both, I just can't stop myself from trying again after my umpteenth manual torpedo strike goes everywhere but where I was aming.
-or after accidentally becoming a war criminal and a rogue after sinking merchant ships before open hostilites had been sanctioned by central command ...I didn't mean to, honestly!

Check out Dick O'Kane and the other manual targeting videos here. There are tons of great tips on manual torpedo shots. As for sinking merchant ships, those videos will set you up enough that you can focus on IDing the flag.

So if one of you seasoned, salty submarine aces out there could answer some torpedo questions for me I would greatly appreciate it.
-the following questions are mostly related to Silent Hunter 4.


First, what is the purpose of adjusting torpedo depth?

ID the ship and you can figure out the best depth to fire at. Depending on the level of realism you're running (particularly which mods you were doing), you've got to be careful aiming low. But, if you don't have a mod that affects running depth (RFB, TMO, etc), you can comfortably aim your torps at 2-3 feet shallower than the draft of the boat you're firing at. Otherwise, aim it about 10-15 feet shallower than the draft of the boat you're firing at (in otherwords, aim it as shallow as possible all the time till 1943 or so).

What is the purpose of tampering with torpedo speed?
-why shouldn't I just set it to MAXIMUM speed?

Slower speeds give you longer ranged shots. That's largely the only thing I've figured out, I'll leave an admiral to answer for that.

Should I generally always aim for the sealine when trying to sink ships with my deck gun?

Generally yes.

Am I right in assuming that AP shells are for warships and HE shells are for merchants?

Historically, there is no evidence that AP shells were ever carried on submarines. So you could argue that you shouldn't use AP shells. But otherwise, basically yes.

Any input is greatly appreciated
-please excuse any English typos or grammtical oddities, I'm Norwegian.

No problem, thanks for the questions!

[Rockin Robbins]

Welcome aboard the good ship Subsim. I appreciate that you are spending your required posts to actually ask some meaningful questions. And we're all rubbish to start. Don't let that intimidate you!

Torpedo speed: The real captains thought as you do, set the suckers to maximum speed and be done with it. In fact the Mark 14, two speed torpedo was later replaced by the one-speed but identical in all other respects Mark 23.

There is always error in targeting solutions. The introduction of radar made these errors a lot smaller, but some error is still in place. So of primary importance to successful submariners was the use of error tolerant procedures--those that assumed that errors existed, anticipated the amount of that error and modified the technique so that the error no longer mattered.

If you have an error of any size, there are a number of things to make the error less important. I'll list them in order of importance.

1. Range! The longer the range, the more important error becomes. A one degree bearing error at 56 feet away is an error of 1 foot. At 5600 feet away, that error is now 100', plenty long enough to miss your target entirely. Now that is 2800 yards. Imagine the folly of shooting 3000+ yard ranges! Unavoidable error means guaranteed misses.
2. Torpedo speed! The less time the torpedo is running, the shorter time for errors to exert their effects. Let's illustrate by pretending to shoot with the torpedo doors closed. The shot will be delayed by about five seconds while the door opens. At a range of one mile on the fast setting, 46 knots, the torpedo would hit the target in 68 seconds. It would take 101 seconds for the slow speed torpedo. The effect is just the same as range: your error is inversely proportional to torpedo speed. Faster is better because it is more error tolerant. Torpedo speed is just as important as range in mitigating error.
3. Depth setting! Especially early in the war, torpedoes tended to run deeper than set. Run all torpedoes set shallow as possible unless you're shooting at a battleship. Then aim about 10 feet above the keel.

Now what errors are important? Here there are stark differences between what matters and what does not. Here they are in order of importance.

1. Target speed error! This rightly is number one through five because it is many times more important than all the other errors. When you are off a couple of knots on a slow target, you're really mucking up the setup. Let's say the target is going 5 knots but you've pegged it at 10 knots by mistake. Your lead angle for your torpedo will be half of what it should be. Can we call that a miss? Maybe not! If you are 500 yards away, shooting with a fast torpedo, you'll still get hits, even with that huge error!
2. Target range error! This is sorta related to speed error. We're calculating how many degrees per second the apparent movement of the target is and leading it by that many degrees to hit it. If our target is at 2000 yards but we've measured 1000 yards, the number of degrees per second it moves is going to be half what we expected. We're going to shoot way in front of him. The closer to him you are, the less that matters. And as a bonus, the closer you are, the smaller your measurement errors will be too! Get that double benefit. Get in DARNED close to take your final range and shoot him when 500 to 800 yards away.
3. Bearing errors and angle on the bow error! These, believe it or not, are not so important at all. You have huge capacity to hit targets when these are set 10 or 15 degrees off! AoB is even less important than bearing. A good estimate is generally good enough unless you're taking that 2000 yard plus shot for some imaginary bragging rights.

Don't be that guy! Take the best measurements you can! Get in so close you can smell their body odor! Shoot spreads of three torpedoes at first so you can tolerate even more error. You'll get your hits.


Then, as you notice that you're hitting three of three all the time and two is all you generally need to get a sinking you can save some torpedoes. In convoy battles I generally shoot one per target, figuring that he'll be hit, drop out of formation and I can mop him up afterwards. But if I need to put him on the bottom it's two torpedoes every time.

[Sailor Steve]

WELCOME ABOARD!

Doulos05 answered most of your questions, but I'll put in my two cents as well.

Originally Posted by Ovedius

In all honesty I am posting to raise my daily download limit.

Nothing wrong with that. The reason that requirement is there is to get people more involved in the community. Hopefully you will see how friendly we usually are and want to post more.

I have recently been stricken by an insatiable apetite for Silent Hunter 4 and 3.

It is an addiction, but one we all enjoy.

Though I am absolute rubbish at both, I just can't stop myself from trying again after my umpteenth manual torpedo strike goes everywhere but where I was aming.

I am no good at manual targeting. Unlike you, I gave up trying long ago.

-or after accidentally becoming a war criminal and a rogue after sinking merchant ships before open hostilites had been sanctioned by central command ...I didn't mean to, honestly!

I can't help you there. Give my regards to the firing squad.

First, what is the purpose of adjusting torpedo depth?

With a contact exploder you want the torpedo to hit as close to the surface as possible. Deeper down the hull curves, and the torpedo might bounce off. With a magnetic exploder you want the torpedo to go off right under the keel. This causes more damage and might even break the ship's keel. Also you might want the torpedo to pass under screening destroyers so they can hit the merchants.

Being able to make that choice is a good thing.

What is the purpose of tampering with torpedo speed?
-why shouldn't I just set it to MAXIMUM speed?

As was said, with slower speeds you can shoot from farther away. If there is a heavy destroyer screen this gives you a better chance of escaping.

Should I generally always aim for the sealine when trying to sink ships with my deck gun?

That will help the ship sink faster, so yes. Hitting the guns of course can destroy them, but if a target has guns it's best to dive and use torpedoes anyway. Hitting the bridge can cause loss of control in the target, and hitting the radio room helps ensure that they don't call for help. Hitting the hull can cause more fires and explosions.

Am I right in assuming that AP shells are for warships and HE shells are for merchants?

That's a fair assumption, but it creates a problem. Destroyers are unarmored, so you don't need AP shells. The smallest ships to carry armor were light cruisers. While a deck-gun AP shell might penetrate that armor the cruiser will be shooting back at you with a minimum of six 6" guns, and he has a very good gun director to do it with. Not a good idea. Even a destroyer has at least four guns every bit as good as yours, and it also has gun directors. If the game lets you win a gun battle with a destroyer, the game is broken.

-please excuse any English typos or grammtical oddities, I'm Norwegian.

Don't worry about it. We have a lot of native English-speakers here who don't write as well as you do.

[joegrundman]

Target range error! This is sorta related to speed error. We're calculating how many degrees per second the apparent movement of the target is and leading it by that many degrees to hit it. If our target is at 2000 yards but we've measured 1000 yards, the number of degrees per second it moves is going to be half what we expected. We're going to shoot way in front of him. The closer to him you are, the less that matters. And as a bonus, the closer you are, the smaller your measurement errors will be too! Get that double benefit. Get in DARNED close to take your final range and shoot him when 500 to 800 yards away.

Rockin Robbins, this is simply wrong, although you do say it very well, and your final tactical recommendation remains sound.

range is a factor for the following reasons:

a) the effects of errors, as you rightly said earlier, are increased with greater range

b) when plotting without the use of radar (or map contact) derived ranges, errors in range can lead to errors in target course and speed estimates

c) with curved fire (with large gyro angles) the effect of torpedo tube parallax (ie the difference in "view" between the view from the scope in the center of the submarine and the view from the torpedo after it has left the tube and turned to intercept the target) causes significant errors when range is incorrectly entered.

With straight fire, that is with a gyro angle of around 0, range becomes irrelevant. You may set any range you please and it will have no effect on whether you hit the target so long as speed is entered correctly, and aob not hopelessly wrong.

p.s. hello ovidious

[Rockin Robbins]

Joe, of course I'm assuming that the OP does not know the difference between straight and curved fire and just enters his measurements without consideration of gyro angle.

In your scenario, range STILL matters, as a wrong range estimate results in error #1 bad speed measurement. The result is still a miss. After all, if the target is twice as far away as you thought, you plot the bearings on that line for a 3 minute speed run, your speed will be double his actual speed. That will result in a miss, yes, from an error of target speed, but that error was caused by your wrong range. edit: Oh! You actually said that. Never mind..... But that's why I said it was sort of related to target speed error.

Radar is your friend! Constant bearing firing techniques and minimizing gyro angles solve SOME problems, but they are no final solution! The ways to screw the pooch always outnumber the ways to make booms.

[joegrundman]

i see, you were just talking about the importance of range when plotting target course and speed. not at the time of calculating firing solution. Then, i'm sorry for the misunderstanding.

when plotting by stadimeter, without map contacts or radar, eg when playing a 1942 scenario, then i find adding eyeballed aobs to the plot helps smooth out range-based errors as per this example

[twm47099]

I'm nubie who needs positive reinforcement. So I play with the "let's dream along with the Torpedo Factory" settings (no torpedo problems.)

With those settings, I usually set the torpedo depth a few feet deeper than the target's draft and set the exploder to influence + contact. That way more sunk ships with fewer torpedoes.

My biggest error in obtaining the firing solution is getting the range from the periscope. Usually, I set high on the stadimeter which = shorter range than actual, which usually equals miss behind. I also have not been very successful using Sonar ranges (seems to measure long). Using the radar in Optical Target Correction mod gives me very good estimates of range, but not all subs have radar. One way to cheat is to leave the scope up and with "contacts shown on the chart" measure the range directly on the chart -- You can pretend that your exec is top notch on the scope. But I prefer to not do that.

So I try to use one of the constant bearing attack methods. Three methods are summarized here:

http://www.subsim.com/radioroom/show...&postcount=204

One nice thing is that they make range insignificant (of course you have to be in range.)

This thread is a must read to get started:

http://www.subsim.com/radioroom/showthread.php?t=146795

Using the constant bearing methods, you should be able to sink at least one or two ships in an attack.

Right now, I'm trying to learn how to break into an escorted convoy, sink some targets, and escape.

Good luck

Tom

[doulos05]

Originally Posted by twm47099

Using the constant bearing methods, you should be able to sink at least one or two ships in an attack.

Right now, I'm trying to learn how to break into an escorted convoy, sink some targets, and escape.

Good luck

Tom

Tom, My preferred exit from a convoy is out the opposite side I entered from, preferably passing directly underneath an undamaged freighter. I say 'undamaged' because I tried this tactic once and went under a sinking one, it met me just as I reached the thermal. To say the results weren't pretty is an understatement, to avoid that mistake, use the attack map and steer towards screws. If the screws are turning, he's floating. This has at least 4 major benefits.
1) The enemy will look on the side of the convoy the torps came from, so all the escorts are on the wrong side.
2) Escorts tend to avoid 'breaking ranks' and moving through the freighter lines, they tend to move around them. They definitely have a pre-programmed 'minimum safe distance' with regard to proximity to merchants, particularly live ones. Not sure how realistically this is modeled, but the noise of the merchants should foil the DD's sonarman as well.
3) The time it takes to get through the lines is roughly the time needed to dive from periscope to the thermal layer, camp a bit, and then come back.
4) When you come back on the other side, you get a hurried escort-free shot at the other side of the convoy with your stern tubes. You're gonna have to eyeball it, very little time for observations or plots (and they're evading anyway so it wouldn't matter). Set them all shallow and guess the speed (most merchants fall in certain top-speed brackets you can learn to ID). Troop Transports and Liners are the fastest, so always hit them on your first pass when you've got measured speeds, this shot is for tankers, freighters, etc that you missed. Those all average around 10-12 knots at top speed. Use the spread dial to throw out 3 torps with a 2-5 degree spread (eye ball it based on how big the target looks in your periscope, but basically fire at -2, 0, +2 or -5, 0, +5, or something in the middle of that) at the ship closest to 180 in the scope, then go deep again. Then, cut towards the rear of the convoy and try to pass under the last merchant in the line. Chill out under the thermal for about 30 minutes or till the escorts get bored, then come back and mop up whatever isn't headed to the bottom yet.

[Ovedius]

Thank you for all the replies, I really wasn't expecting so many.

All the advice and guidance is greatly appreciated.
I'll just head over to the Skipper's Bag of Tricks thread and see what I can learn.

Oh, a couple of last questions.


Is the AI in the Convoy Attack Tutorial reduced in some way?


Let me explain:

I play vanilla SH4 with the GFO mod. -Game Fixes Only mod.
So I've been replaying the convoy attack tutorial mission to learn the ropes.
Generally I play with most realism boxes ticked, except map contacts.
-I use the nav map to estimate the AOB...I'm a bit of a cheat, I admit it!

But yesterday something peculiar happened.

In a furious fit of frustration over another botched torpedo strike I decided to go kamikaze and surface, deck gun blazing.

(I should perhaps mention that I did infact hit two tankers with one torpedo each....I wasn't aming at the second tanker but let's gloss over that.
They both, however, stubbornly refused to sink.)

I thereafter succeeded in sinking three destoyers and two-three trading ships while circling and racing through the convoy at flank speed.

I was pretty much only under fire from one destroyer at a time.

I was eventually sunk by continous fire from the remaining trade ships (or damage delivered by the, by now, sunk destroyers)

Clearly this was either insane luck, preposterous skill or severly gimped opposition.
I think we can safely say that skill was not a contributing factor, so a combination of luck and gimped opposition?


Should I instead get my practise from the available single missions?




And while we're all still friendly and patient:

Considering my relative success at deck gun duelling above, do you think I should, as a N00B, try any of the realism mods?
-Either RFB or TMO for a slight increase in "realism"?

From what I've read of Trigger Maru it does sound like it might be a little to difficult for my tastes.
-and I didn't quite like the map contacts "dots" that replaced the default ship outlines

[Rockin Robbins]

Originally Posted by joegrundman

That graphic is a thing of beauty! What a simple thing it would have been to have each periscope stadimeter observation plotted like that automatically and then let us average the points! Had the devs just spent a week in the torpedo firing manual this would have been a better game!

[joegrundman]

Originally Posted by Rockin Robbins

That graphic is a thing of beauty! What a simple thing it would have been to have each periscope stadimeter observation plotted like that automatically and then let us average the points! Had the devs just spent a week in the torpedo firing manual this would have been a better game!

[doulos05]

Originally Posted by joegrundman

i see, you were just talking about the importance of range when plotting target course and speed. not at the time of calculating firing solution. Then, i'm sorry for the misunderstanding.

when plotting by stadimeter, without map contacts or radar, eg when playing a 1942 scenario, then i find adding eyeballed aobs to the plot helps smooth out range-based errors as per this example

OK, I thought to myself, "Just stare at it longer and it will make sense." I stared at it longer, it still doesn't make sense. Can someone explain what I'm looking at?

[bill clarke]

Great thread, raised some questions from me.

1. I like the idea of going under a convoy to escape, the problem with this modus operadi is if there is really shallow water on the other side, also I've noticed DD's on that side, who sometimes stay on the unengaged side.

2. Why can't the torp seetings be adjusted with auto targeting on, you could do that in SHIII, and in the German campain in SHIV WOP Gold edition, is there a mod to allow you to do this ?

Some obs from me, since installing RSRD after reinstalling SHIV, the torps seem much more destructive, on my first patrol, I ran into a TF 6 DD's 2 Kongo's 1 Takeow, and 1 Agano (yes, in Dec 41) 3 fish at 2000+ yards at the lead BB 3 hits, she quickly came to a halt and began listing.

I fired my last bow fish at Takeow, and turned to port to fire my stern tubes at the 2nd BB. I got a hit on Takeow in the bow, all 3 fish hit the second BB, with the last on abreast the rear turrets. Got a magazine explosion and she was gone real quick.

I aimed the last fish at Takeow's mid section but she must have seen it and increased speed, net result the fish hit abreast the rear turrets, another magazine blast and she was gone in a minute.

[twm47099]

Originally Posted by bill clarke

Great thread, raised some questions from me.

1. I like the idea of going under a convoy to escape, the problem with this modus operadi is if there is really shallow water on the other side, also I've noticed DD's on that side, who sometimes stay on the unengaged side.

2. Why can't the torp seetings be adjusted with auto targeting on, you could do that in SHIII, and in the German campain in SHIV WOP Gold edition, is there a mod to allow you to do this ?

I adjust the torp settings (if you mean speed, exploder, angle, and depth) in auto targeting. It's one way I spread my shots. I am using the Optical Targeting Correction (OTC) mod, but I also did that in stock (SH4, v 1.5)

Tom