SH4 Targeting

Majestik 909 · 12-21-15, 03:37 PM

Interestingly, the lock in periscope view always focuses dead amidships. What is a good targeting method when you prefer a bow or stern shot?

SilentPrey · 12-21-15, 09:47 PM

I've been using the O'Kane method and firing as the part of the ship that I want to hit crosses the wire. The other thing you can do if you want to have it locked while you fire is to offset the angle that you want to hit ahead or behind the wire. That's a bit trickier; at 500 yards 1 degree of offset will move the impact far less than at 5,000 yards. I haven't done that math, sorry.

Majestik 909 · 12-21-15, 10:29 PM

Thanks, Silent...

SilentPrey · 12-21-15, 10:32 PM

No problem. Happy hunting!

TorpX · 12-21-15, 10:54 PM

Quote:

Originally Posted by Majestik 909

Interestingly, the lock in periscope view always focuses dead amidships. What is a good targeting method when you prefer a bow or stern shot?

Ummm.... not sure why you would want a bow or stern shot.

In any case, to use the offset dial, as suggested by SilentPrey, estimate the angular length of the target. This can be done by unlocking the scope finding the bearing of the stern, then the bow, and taking the difference. Then use an appropriate offset for your spread.

For example:

A tanker at AOB 120° has it's stern at bearing 258°, and bow at 261.5°. This means it has an apparent angular length of 3.5°. So, for a 3 torpedo spread, we can launch one torp at -1.0°, one with no offset, and one with +1.0°. This will give us 57% coverage [2°/3.5°].

Of course, you could use more or less. Generally, RL skippers used 80 to 100%, but I suppose it would depend. The estimate of apparent target length should be done shortly before lauching, as changes in the AOB, or range, would make the result different.

The above method does not take into account target movement, changes in range (between firing and impact), or such, but should suffice for our purposes.

The main reasons for using a spread is to increase the chances of a hit, and to increase the damage to the target. If you were only going to fire one torpedo, it should really be at the middle of the target. This would allow for the greatest error.

************************************************** **

Welcome back from shore leave, SilentPrey!

I haven't seen you around for a while.

Taking a break from your saltwater adventures, I suppose?

ColonelSandersLite · 12-21-15, 11:43 PM

TorpX is right on the money with using spread, I just thought I would add one cautionary note (from experience when I was still a noob). We'll use a fresh example of target's bow is at bearing 350° and targets stern is at bearing 340° for an apparent length of 10°.

It is very important to note that this is total ship length, and it is easy to screw up by just jumping to the conclusion that 10° is the maximum spread angle. Suppose that, having made this mistake, you then decide to divide that by 2 to hit in the middle of the bow half. This gives a an incorrect spread angle of 5°. Assuming that the target takes no evasive action, that actually puts the torpedo right at the tip of the bow/stern and has a high probability of missing, depending on which way the errors in your firing solution go. So, just remember that since your zero point is ship's dead center, maximum spread is "apparent angular length / 2", not just "apparent angular length".

In truth though, with experience you will probably just come up with some internal rules of thumb on spread depending on target range. It's very, very, very rare that I actually go to the effort to do it like that.

ColonelSandersLite · 12-22-15, 12:09 AM

Assuming manual targeting, there are two other primary methods of targeting specific parts of a ship that I routinely use. There may be more I don't use and so they aren't coming to mind.

First, when you are shooting without the position keeper active:
Point the periscope at the bearing you will shoot at and enter the parameters into the TDC for where the target will be *when you fire will fire*. You fire your torpedoes as the ship crosses the centerline of the periscope. Assuming that your targeting data is correct and the target does not evade, you will hit the part of the ship that was at the periscope's center line at the time of firing. From all the talk and tutorial video's I've seen around here, this is mostly done with firing solution where torpedo gyro angle is at or near 0 (but doesn't have to be). This method works by introducing a deliberate offset into the lead angle.

Second, with the position keeper active:
Enter targeting data into the TDC normally. Just before you want to fire, update range and bearing with a fresh stadimeter reading and send to the TDC. Unlock the periscope and point it just ahead of the part of the ship that you want to hit. As the part of the ship that you want to hit is crossing the centerline of the periscope, resend the range and bearing. Fire at will. This method works by introducing a deliberate offset into the data for the target's position.

While they are not TDC tutorial videos, I used both of these methods in my advanced convoy attack tutorial series.

I think the following works, but I'm not 100% sure since I haven't really used automatic targeting outside of a few experiments.

When using automatic targeting, there is one other useful method. Point the periscope just ahead of the part of the ship that you want to hit. DO NOT lock the periscope. As the part of the ship that you want to hit crosses the centerline of the periscope, fire your torpedo.

Majestik 909 · 12-22-15, 11:25 AM

Col and Torpx - Many thanks. I really appreciate your experience.

I am not as skilled as you gentleman and your information helps greatly. I am a patient hunter. I usually pursue a convoy for many real time hours, closing to under a 1000 meters before firing a near perfect shot into my target from a point a few degrees off its bow. I also like to watch activity on deck as i am lining up for a shot.

Your methods have me intrigued and I want to experiment with them. I may have to ask you both some questions.

I got into some real trouble on a recent mission. U-796 was assigned to engage a convoy before it arrived in Port Elizabeth. I managed to intercept the convoy near Seychelles. To my surprise, my target was a Titanic-esque liner with lots of men walking along deck with at least 6 destroyer escorts. Since the liner was zig-zagging and blacked out, I began my approach through the escorts.

The destroyers were quick to detect me and I was soon working hard to avoid being sunk. I managed to close on the liner and hide by staying a few hundred yards off it's stern and anticipating its course changes.

I spent many hours hiding iin this fashion. Each time the liner would make a greater course deviation I would again be attacked.

Finally, with battery power getting low I decided to attack in dramatic fashion. I noticed the liner had no depth charge racks or guns, so I surfaced along it's starboard side while all escorts were on the port side. I saw two destroyers approaching the liner on a course that would take them across its port bow.

I set my pistols to magnetic, depth 1.5 meters on a course of 000. I fired in some way as one would fire at an aircraft. Not really aimed, but I figured I could hit them. I hit both destroyers and sank them both. I immediately submerged to periscope depth and used a combination of back emergency and full rudder to open distance between me and the liner as she turned to avoid the sinking destroyers. I was amazed to see the liner accidentally ram and sink an old freighter that was in the convoy.

I managed to line up on the liner at about 400 meters maybe 30 degrees off the starboard bow. With escorts in pursuit I just locked the liner in my periscope view and fired 3 fish. I began a crash dive at flank speed as soon as the last fish cleared the tubes. I set depth for 120 meters and waited for the depth charges. I heard three torpedo impacts snd curiously looked at the surface camera view to see the liner listing to starboard and on firr with many lifeboats in the water.

What followed was hours of being pursued and depth charged. I was finally able to surface at night in a storm and eventually made it back to Batavia. The liner, which is shown in the log i posted here previously, netted some serious tonnage.

I am eager to employ the methods you have described, but I am having a little trouble with the math.

Majestik 909 · 12-22-15, 11:56 AM

Colonel - I have been maneuvering for a near perfect zero degree heading shot. This takes a lot of time, but I enjoy it. I have read some guys like to run a parallel course and fire a torpedo that turns into the target.

Is any approach considered optimal in your opinion?

SilentPrey · 12-23-15, 03:50 AM

Quote:

Originally Posted by TorpX

Welcome back from shore leave, SilentPrey!

I haven't seen you around for a while.

Taking a break from your saltwater adventures, I suppose?

You could say that. I'm finally back in college. (Dozen year break.) Turns out that learning Latin doesn't leave much time for Maru harassment. Now that finals are over I've time to play and troll the forums.

Majestik,

You were using Kentucky Windage and getting hits? I'm very impressed. You're one of those guys that left on the Oregon Trail with just a rifle and a wagon load of bullets, aren't you?

I'll confess that I have never played a U-Boat in SH4. I never got the impression that the mods for the U-Boat side came anywhere near SH3 with GWX so that's what I use for the other side. That said; the O'Kane method should serve you well in U-boats too.

Here's where Rockin Robbins details the process for both the O'Kane method and the Fast 90. Enjoy! http://www.subsim.com/radioroom/show...6&postcount=67

SilentPrey

12-21-15, 03:37 PM	#1
Majestik 909 Planesman Join Date: Dec 2015 Location: California Posts: 195 Downloads: 0 Uploads: 0	SH4 Targeting Interestingly, the lock in periscope view always focuses dead amidships. What is a good targeting method when you prefer a bow or stern shot?

12-21-15, 11:43 PM	#6
ColonelSandersLite Captain Join Date: Aug 2009 Posts: 481 Downloads: 74 Uploads: 3	TorpX is right on the money with using spread, I just thought I would add one cautionary note (from experience when I was still a noob). We'll use a fresh example of target's bow is at bearing 350° and targets stern is at bearing 340° for an apparent length of 10°. It is very important to note that this is total ship length, and it is easy to screw up by just jumping to the conclusion that 10° is the maximum spread angle. Suppose that, having made this mistake, you then decide to divide that by 2 to hit in the middle of the bow half. This gives a an incorrect spread angle of 5°. Assuming that the target takes no evasive action, that actually puts the torpedo right at the tip of the bow/stern and has a high probability of missing, depending on which way the errors in your firing solution go. So, just remember that since your zero point is ship's dead center, maximum spread is "apparent angular length / 2", not just "apparent angular length". In truth though, with experience you will probably just come up with some internal rules of thumb on spread depending on target range. It's very, very, very rare that I actually go to the effort to do it like that. __________________ My SH4 LP

12-22-15, 12:09 AM	#7
ColonelSandersLite Captain Join Date: Aug 2009 Posts: 481 Downloads: 74 Uploads: 3	Assuming manual targeting, there are two other primary methods of targeting specific parts of a ship that I routinely use. There may be more I don't use and so they aren't coming to mind. First, when you are shooting without the position keeper active: Point the periscope at the bearing you will shoot at and enter the parameters into the TDC for where the target will be when you fire will fire. You fire your torpedoes as the ship crosses the centerline of the periscope. Assuming that your targeting data is correct and the target does not evade, you will hit the part of the ship that was at the periscope's center line at the time of firing. From all the talk and tutorial video's I've seen around here, this is mostly done with firing solution where torpedo gyro angle is at or near 0 (but doesn't have to be). This method works by introducing a deliberate offset into the lead angle. Second, with the position keeper active: Enter targeting data into the TDC normally. Just before you want to fire, update range and bearing with a fresh stadimeter reading and send to the TDC. Unlock the periscope and point it just ahead of the part of the ship that you want to hit. As the part of the ship that you want to hit is crossing the centerline of the periscope, resend the range and bearing. Fire at will. This method works by introducing a deliberate offset into the data for the target's position. While they are not TDC tutorial videos, I used both of these methods in my advanced convoy attack tutorial series. I think the following works, but I'm not 100% sure since I haven't really used automatic targeting outside of a few experiments. When using automatic targeting, there is one other useful method. Point the periscope just ahead of the part of the ship that you want to hit. DO NOT lock the periscope. As the part of the ship that you want to hit crosses the centerline of the periscope, fire your torpedo. __________________ My SH4 LP

12-22-15, 11:25 AM	#8
Majestik 909 Planesman Join Date: Dec 2015 Location: California Posts: 195 Downloads: 0 Uploads: 0	Col and Torpx - Many thanks. I really appreciate your experience. I am not as skilled as you gentleman and your information helps greatly. I am a patient hunter. I usually pursue a convoy for many real time hours, closing to under a 1000 meters before firing a near perfect shot into my target from a point a few degrees off its bow. I also like to watch activity on deck as i am lining up for a shot. Your methods have me intrigued and I want to experiment with them. I may have to ask you both some questions. I got into some real trouble on a recent mission. U-796 was assigned to engage a convoy before it arrived in Port Elizabeth. I managed to intercept the convoy near Seychelles. To my surprise, my target was a Titanic-esque liner with lots of men walking along deck with at least 6 destroyer escorts. Since the liner was zig-zagging and blacked out, I began my approach through the escorts. The destroyers were quick to detect me and I was soon working hard to avoid being sunk. I managed to close on the liner and hide by staying a few hundred yards off it's stern and anticipating its course changes. I spent many hours hiding iin this fashion. Each time the liner would make a greater course deviation I would again be attacked. Finally, with battery power getting low I decided to attack in dramatic fashion. I noticed the liner had no depth charge racks or guns, so I surfaced along it's starboard side while all escorts were on the port side. I saw two destroyers approaching the liner on a course that would take them across its port bow. I set my pistols to magnetic, depth 1.5 meters on a course of 000. I fired in some way as one would fire at an aircraft. Not really aimed, but I figured I could hit them. I hit both destroyers and sank them both. I immediately submerged to periscope depth and used a combination of back emergency and full rudder to open distance between me and the liner as she turned to avoid the sinking destroyers. I was amazed to see the liner accidentally ram and sink an old freighter that was in the convoy. I managed to line up on the liner at about 400 meters maybe 30 degrees off the starboard bow. With escorts in pursuit I just locked the liner in my periscope view and fired 3 fish. I began a crash dive at flank speed as soon as the last fish cleared the tubes. I set depth for 120 meters and waited for the depth charges. I heard three torpedo impacts snd curiously looked at the surface camera view to see the liner listing to starboard and on firr with many lifeboats in the water. What followed was hours of being pursued and depth charged. I was finally able to surface at night in a storm and eventually made it back to Batavia. The liner, which is shown in the log i posted here previously, netted some serious tonnage. I am eager to employ the methods you have described, but I am having a little trouble with the math. Last edited by Majestik 909; 12-22-15 at 03:34 PM.

12-21-15, 09:47 PM	#2
SilentPrey Navy Dude Join Date: Feb 2011 Location: Texas Posts: 171 Downloads: 58 Uploads: 2	I've been using the O'Kane method and firing as the part of the ship that I want to hit crosses the wire. The other thing you can do if you want to have it locked while you fire is to offset the angle that you want to hit ahead or behind the wire. That's a bit trickier; at 500 yards 1 degree of offset will move the impact far less than at 5,000 yards. I haven't done that math, sorry.

12-21-15, 10:29 PM	#3
Majestik 909 Planesman Join Date: Dec 2015 Location: California Posts: 195 Downloads: 0 Uploads: 0	Thanks, Silent...

12-21-15, 10:32 PM	#4
SilentPrey Navy Dude Join Date: Feb 2011 Location: Texas Posts: 171 Downloads: 58 Uploads: 2	No problem. Happy hunting!

12-22-15, 11:56 AM	#9
Majestik 909 Planesman Join Date: Dec 2015 Location: California Posts: 195 Downloads: 0 Uploads: 0	Colonel - I have been maneuvering for a near perfect zero degree heading shot. This takes a lot of time, but I enjoy it. I have read some guys like to run a parallel course and fire a torpedo that turns into the target. Is any approach considered optimal in your opinion?