Coriolis

[Crannogman]

Currently patrolling the Sea of Japan off Hokkaido, I've noticed a much higher torpedo miss rate than usual. A lot of my fish have been running straight but passing astern, such that I have to set a 1-degree offset ahead of the ship to connect. It doesn't seem to make a difference whether I use bow stern tubes, nor AoB. And I am quite vigilant to get the doors open before firing. Mostly the ships have been heading close to 180-degrees, but one was about 75 and had the same issue.

I am fairly certain that SH4 does not model the Coriolis effect per se, but possibly it has to due with the Mercator projection used by the game map. This is the highest latitude in which I have fought, where distortion would be most apparent. Any thoughts or similar experiences?

[CapnScurvy]

You could be in error of the target speed not being high enough? How do you estimate speed?

As far as I know about the game, there's little chance the Dev's put enough physics into the game to make the Coriolis Effect have a factor. There's no Magnetic Declination either within the game. North is at the top of the map.....and that's that.

What I know about the Coriolis Effect is that the northern hemisphere has the effect turning in a clockwise motion. With a clockwise rotation the deflection of the object is to the left of motion of the object. So your torp should be missing to the left of your aim......not to your right. Doing so no matter from which direction the target is traveling.....from your left or right.

[Crannogman]

What's oddest is that the torpedoes even miss the white X on the tactical map when the position keeper is on. I know the Coriolis effect isn't likely to be modelled - but the Mercator projection does alter east-west distances near the poles, and I think (recalling mostly from SH2 and Destroyer Command) that that distortion is noticeable in game

[TorpX]

Whatever the issue is, it isn't the coriolis effect or map projection issue. As far as SH is concerned, the earth is flat, and map projection distortion would only come into play, if you are using a proper, real-world map/globe in conjunction with the game map. The SH4 universe may not be accurate, but it is consistent.

What mods do you use, and what conditions were you attacking in?

[Crannogman]

RSRDC, OTC, NMMO. Conditions were varied, 0-6 kt winds, clear to light fog, ranges 800-1500y. I hadn't changed any mods since my last patrol, when things ran straight and true; I do think a Mk18 snuck in there, but everything was a 14. I guess nobody else has had this issue

[les green01]

never had that problem usualy if i miss it is me aob or speed off

[TorpX]

Originally Posted by Crannogman

RSRDC, OTC, NMMO. Conditions were varied, 0-6 kt winds, clear to light fog, ranges 800-1500y. I hadn't changed any mods since my last patrol, when things ran straight and true; I do think a Mk18 snuck in there, but everything was a 14. I guess nobody else has had this issue

I can only think of a couple things that might produce such a problem. One, your torps are plowing the wave crests and being slowed down (unlikely, I guess); two, you left the offset dial on the torpedoes set in such a way, that they are sending them behind the TDC calculated course.

Otherwise, I would imagine it is ordinary errors that are involved.

[Hambone307]

Now that I think about it, I had this problem with auto targeting a while back. It didn't matter if I locked on to the target, aimed at the bow, or at the stern, they all passed just behind the ship. The problem more or less resolved itself and I never looked into it much. Just attributed it to the "poor performance" of the Mk14s.

[Armistead]

Never had that problem unless one of my values was off somewhat. If you want a perfect AOB, it will always be the enemies course relative to your sub. You can set the heading for the enemy on your AOB wheel, so if his course is 180, just adjust until the arrow is lined up on 180 on the AOB wheel to the left and activate.

Sometimes judging speed using the stad can be off unless you get precise measurements, better to use the 3 minute rule.

I also like shooting spreads by the wire than using the clumsy offset wheel. Once I have all my settings on the TDC using the lock function on the ship, I unlock, and shoot by the wire, simply place the crosshairs on the ship where i want to aim and click a new bearing and fire. Generally, first shot will be near the bow, next MOT, last stern. Obvious single merchants I often will just shoot one and generally aim for the stack. Just remember to send a new bearing for each shot or aiming point.

[Crannogman]

I deeply respect the knowledge and experience base you guys bring to the table. I have not yet gotten to the point where I am ready for manual targeting; I plan to change up my mods and realism after this (my first SH4) career.

So a lot of the knowledge bombs you are dropping are delayed fuse, whereas air-burst might be more effective. I think the most salient point is that my torpedoes even missed the white X on the tdc map. I don't recall such issues in the past (since Dec '41). I've engaged all manner of surface vessels in all conditions at all reasonable ranges and AOB, and don't recall such glaring and repetitious difficulties. One of the esteemed commenters mentioned having a similar transient issue with auto-targeting, which I suspect is the same.

My initial question was whether this was a latitude issue. My patrol has worked its way down to Oshima and the issue remained. So I think it is likely some other problem with auto-target that will hopefully auto-correct

[CapnScurvy]

Originally Posted by Crannogman

......I am quite vigilant to get the doors open before firing.......I think it is likely some other problem with auto-target that will hopefully auto-correct

With auto targeting, just about the only thing you'll need to do is open the tube doors.....and make sure they are still open just before firing.

Granted, another error modifier is used if you stray with more than a 15 degree relative bearing angle when firing (the triangle will turn yellow). Other than that, there's not much that can go wrong with the torpedo track. The very issue of having the torpedo track behind the target becomes noticeable due to the lag time in having to open them automatically when firing.

There is one thing you might consider, don't expect the tube doors to stay open for an unlimited amount of time after opening them. They will close after a certain amount of time on their own. Since there's not a way of knowing when the doors are open or not (besides pressing the "Tube Door" toggle switch) it could be the doors are closing......giving you the lag time error.

[Armistead]

May not be an issue, but I got lots of misses using auto targeting unless close. Another issue with auto targeting is ships often zig, change speed, etc..when they see torps and if they spot u they go into zig patterns, so often u need to be able to shoot where u think a ship will be when the torp arrives, not the current info u have when u fire.

The offset dial is worthless imo, time consuming and hard to figure at range what it should be, learn to shoot by the wire..

[TorpX]

Agree that the offset dial is awkward to use. It would be better, if you could set each torpedo beforehand, instead of having to try to make fine adjustments between each launch, when you are in a hurry.

CapnScurvy's idea about the outer doors closing by themselves might explain the mystery. I've never used auto-targeting enough to have a good feeling for it's limitations.

[Crannogman]

In my experience the outer doors stay open until you close them or go below ~100 ft; I once noticed a door open for about a week

[CapnScurvy]

OK.....OK...... I checked, and I'm full of it!!

I looked at RSRDC v550 with OTC for RSRDC v550. Started a new campaign at war's beginning with the Porpoise at Pearl (just let the game start as default), auto targeting etc.

The Porpoise has 6 tubes. 1 and 3 on the bow starboard side. 2 and 4 on the bow port side. 5 and 6 to the stern, with 6 on the port side. I opened the doors and they didn't close. They were open for over an hour at surface and periscope depth.......they didn't close on their own. The tubes did close after setting the depth to 110 feet......just after passing 103 feet. I visually checked each tube with the outside camera to confirm the correct operation and torpedo firing.......all were correct.

I did not check any other sub class. You didn't mention which sub you're using?

I'm confirming that the Porpoise works as expected. The tube doors do not close automatically, except for the depth limitation and of course, after a firing. I can not say this is true for the remainder of the subs in-game. Not that I know for sure...after all I miss spoke already on the subject, but it's possible one of the other subs does not have the correct tube assignment for the firing order/tube door opening. Just a thought.