Gyroangle Insight

[banryu79]

Originally Posted by TorpX

I think the idea that track angles had to be 90 degrees, or nearly so, and gyro angles zero, or close to it, is something of an old wives tale.

Here is a pertinent quote from Roscoe's US Submarine Operations Of WWII. [I realize this is not the same as KM experience, but geometry is geometry.]

I suspect that was the case not because of trigonometry issue of the target solution, but for the specific problems with the impact pistol of the American torpedo.

The German uboat had their peculiar problem too with the impact pistol but their case called for a perpendicular impact angle between torpedo and target for the pistol to function properly while the American torpedo impact pistol would have its pins bent at such an angle.

[maillemaker]

I shoot at 0 gyro simply because after years of playing I still cannot accurately figure out range or AoB by eye.

Last night I was making an approach on a large convoy at the mouth of the bay west of Gibraltar. They were coming due east and just as I got into visual range the dang thing made a radical change of course to almost due north. December 1941.

I did not want to do an end around so I made a long range shot. I nailed a heavy merchant and a large tanker from probably 6000 meters using T1 torpedoes on medium speed. One hit on the merchant and 2 hits on the tanker. One miss. Both sank.

Steve

[TorpX]

Originally Posted by banryu79

I suspect that was the case not because of trigonometry issue of the target solution, but for the specific problems with the impact pistol of the American torpedo.

You (and others) are confusing the gyro angle and the torpedo track angle. The TTa might be important with regards to the torpedo exploder reliability (or lack thereof), but the gyro angle would not.
No doubt the exploder issues lowered the overall percentages, though.

Take a glance at Aktungbby's diagram.

The gyro angle shown is, let's call it 40 degrees. The Torpedo Track angle is about 100 deg. You can easily have a large gyro and a near "perfect", 90 deg. TTa, or a zero gyro angle and a poor TTa.

In SH (3 or 4, it doesn't matter), people tend to favor 'canned' approaches because they think their hit probabilities are better, and because the game allows this. In real-life, unpredictable target zigs often forced skippers to use larger gyro angles, or pass up the opportunity.

[desirableroasted]

Well said, TorpX. Thank you.

[Aktungbby]

Originally Posted by TorpX

Take a glance at Aktungbby's diagram.

Originally Posted by desirableroasted

Well said, TorpX. Thank you.

[banryu79]

Originally Posted by TorpX

You (and others) are confusing the gyro angle and the torpedo track angle. The TTa might be important with regards to the torpedo exploder reliability (or lack thereof), but the gyro angle would not.
No doubt the exploder issues lowered the overall percentages, though.

Take a glance at Aktungbby's diagram.

The gyro angle shown is, let's call it 40 degrees. The Torpedo Track angle is about 100 deg. You can easily have a large gyro and a near "perfect", 90 deg. TTa, or a zero gyro angle and a poor TTa.

In SH (3 or 4, it doesn't matter), people tend to favor 'canned' approaches because they think their hit probabilities are better, and because the game allows this. In real-life, unpredictable target zigs often forced skippers to use larger gyro angles, or pass up the opportunity.

Thank you for the explanation, sir!

Obviuosly I was wrong, I have make confusion about concepts because I didn't take enough time to read and understand properly the diagram that Aktungbby has posted.

Now I fully understand that quote from Roscoe's US Submarine Operations you cited, and it make sense to me too. Yes, after all geometry is geometry, thank you again.

[in_vino_vomitus]

I don't play SH3, but as has been said, Geometry is geometry. What I've found, playing the German side in OM, is that when you're taking shots with big gyro angles, your target data needs to be pretty much perfect. There's quite a comfortable safety margin in shots taken with a 90 degree approach /zero gyro angle setup. The range is rendered irrelevant for starters, and if your course estimate is out by ten degrees or so, then that needn't matter too much either. It's a very forgiving setup, but as soon as you start shooting sideways, you lose that safety margin. If you want a 90 degree gyro angle shot to hit, then you have to have pretty much 100% accuracy in your target data. Someone with a better head for trigonometry will be able to explain it better than me, but one obvious detail is that if you're aiming at a target abeam, then parallax becomes an issue, because the torpedo is going to be starting its run a hundred or so feet to one side of where you're aiming it from.

Maybe go into the mission editor and set yourself up a 90 degree shot, so that you know your target data is absolutely spot on. if that misses, then you have reason to suspect issues with the game optics, but otherwise it's more likely to be cumulative errors in your course, speed and range estimates.

[Pisces]

Yup, the 90 degree torpedo track angle and 0 degree gyroangle gives the best margin of error to counter any possible mistakes in the data. But by no means impossible to do it otherwise. You just have to be carefull on what data you enter.

The TDC needs to have the right range setting (at the time of firing) to correctly aim the torpedo at large gyroangle deviations (from 0/180). Assuming all other settings like AOB and target speed are correct, and the tubes are open of course.

The correction (to counter the parallax made by the 'reach' and turning radius of the torpedo track) is less for long-distance shots, and more for point-blank range. At short distances the target is larger in angular proportions. So this helps you a bit in evening the odds.

If you steadily notice you have trouble hitting targets in high gyroangle situations, then investigate if, and if so why, the range might not be correct. (use auto map-updates and the pause button to verify your measurements) If you decide you need to fire at the target 'early' along it's track, the torpedo track angle might be small and close to the bow. This presents a smaller target for the torpedo to hit at. (compared to full broadside at 90 AOB) If you decide so, ask yourself why you would need to do this now. Or perhaps wait for better situations/setups.


Rule of thumb? 0 gyro angle if the tactical situation allows it. If you have pinging escorts that you need to point towards to, or away from, then that takes precedence. Also, at one time in very bad weather I decided to parallel along a small string of merchants and match their speed (as I could barely overtake). Gently creeping towards their track until the fog lifted, shoot abreast, and hide in the mists again. Not perfect, but it got the job done.

[TorpX]

Originally Posted by banryu79

Thank you for the explanation, sir!


Now I fully understand that quote from Roscoe's US Submarine Operations you cited, and it make sense to me too. Yes, after all geometry is geometry, thank you again.

You're welcome, one and all. I love these geometry discussions.



I should mention that the conclusions I quoted were unexpected, and pre-war thinking certainly favored zero gyro-angle attacks. The gyro-angle thing was not the only idea to fall by the wayside during the war, either.

Something else that may not be appreciated about the gyro angle business. Motor torpedo boats have little reason to worry about gyro-angles; the torps need only be steered enough to produce a desired spread. The boat itself can quickly turn to an advantageous track. A submerged submarine is another thing entirely. It is much faster to turn the torpedoes, than to turn the sub. For submarines, gyro equipped torpedoes are almost a necessity.

[Tupolev]

@ TorpX - I'd have thought commanders tried zero gryo angle shots IRL, especially early war, but perusing some of the Torpedo Firing Reports in uboatarchive.net has definitely shown me otherwise. There are lots of shots, and hits, at 15-20 gyro angles.

One of the more interesting reports: U-48 shooting at a convoy on Oct. 17, 1940. One shot at 3000m and two at 4000m with a 15.5 gyro angle on each. All hits.

Teddy Suhren was a damn good shot.

T

[TorpX]

Originally Posted by Tupolev

@ TorpX - I'd have thought commanders tried zero gryo angle shots IRL, especially early war, but perusing some of the Torpedo Firing Reports in uboatarchive.net has definitely shown me otherwise. There are lots of shots, and hits, at 15-20 gyro angles.

One of the more interesting reports: U-48 shooting at a convoy on Oct. 17, 1940. One shot at 3000m and two at 4000m with a 15.5 gyro angle on each. All hits.

I would certainly consider 4,000 m to be a good shot at any angle.

My impression of things in the Pacific theatre is that they usually preferred to have zero, or small gyro angles, but that circumstances would sometimes force them to do otherwise. Roscoe mentions one captain (I forget which), who didn't trust the new TDC, and preferred to calculate the angles with the older Mark VIII angle solver. In his approach, the set-up changed and forced him to use the TDC, so he became a believer in it.

I suspect that torpedo problems played a role in all this. By that I mean, torpedo malfunctions (detonation failures) leading to a loss of confidence, and causing captains/crews to believe that set-ups had to be virtually "perfect", to have a good chance to hit. That would be the natural tendency, anyway.