Stadimeter & range estimates....Choppy Waters!
 

Manual targetters: How the $%#* do you get a decent range with the Stadimeter in anything but totally calm water?? I've been using the average technique - like take 3 readings and do a rough average, but in light winds I find my estimates bounce all over the place making it impossible to get a decent range. Without the target speed estimate (which I derive from three or more range estimates), I can't make a good shot.

Second, semi-related issue - how to determine target speed (forget bearing & range - just speed) with the hydrophone? In DW there's a DEMON analysis that one does to determine this. How to do it in SH3? I can line up a shot abeam by eyeballing the AOB, but the speed is hard to get right - an accurate measure by hydrophone could really help and eliminate the need to use the Stadimeter in rough weather.

Kb

I always use the "optics stabilization" feature. I play with manual targetting and without map contacts updates but I'm not THAT masochistic to do so with the reticule bobbing all over the place in anything but calm seas.

You can't measure the speed of a target by hydrophone. You can either use the notepad in the UZO or periscope views to calculate a target's speed (you need to estimate the AOB and distance before and be stopped while taking the time for accurate data) or you can plot down the target on your map (you need bearing and distance), then connect the points and do the math.

I usually use the 2nd method since it's far more accurate for me.

I use the MILS method as opposed to the mast hight method. Much quicker and easier. It gives you the range instantaneously.

There is a sound trainer for SH3 where you can determine speed by the hydrophone through listening.

I usually use the matching speed method, which is easiest if you have favorable conditions.

Could you explain this "MILS Method" Heibges?

At a known distance, any object will appear to have a known length. I think each tick on the periscope is equal to 5 mils, but that is really unimportant. We'll just call each tick on the periscope a unit. The following table is for targets on a perpedicular course and a 0°AoB.

........................Range.............1200m... ........600m
C2 Merchant.............................6units....... ..12units
C3 Merchant.............................7units....... ..14units

I had a chart for all ships and ranges, but I accidently threw it away, and have been procrastinating on redoing it.

I am guessing it is this, but it doesn't explain how.

http://en.wikipedia.org/wiki/Angular_mil

:hmm:

Dude, you're my hero!!

:up:

Although, at 0 AoB isn't it a little late to shoot? More useful for convoy encounters I'd imagine.

I've found determining course and speed so I can setup a Fast 90 shot is more valuable than the actual distance, as the torpedos travel so fast that when you're close enough to actually get distance with the statometer you're within 4k anyway.

However, I suck at determining course...

Matching speeds - i can't imagine doing this well without accurate range estimates. Yer moving along beside a merchant, trying to match AOB and speed, and trying to decide if your target is growing or shrinking in the UZO. I might have to opt for the periscope stabilization. I've been using WO estimates while on surface, which are TRUTH I think, and hence life has been good. But when at peri, there's no speed matching to be done, and it's all about the stadi and the hydrophone. I'm still kinda noobed. I'm going to look into the MILS method. Sounds good. Did they use it in RL?

Kb

Right, you would actually shoot at probably AoB 5° or AoB 10°, so you will have to guesstimate a little the range, but it should get you in easily within 100m+/-.

The range is my final input into the TDC before shooting.

To match speed first you must determine target course, and get on a parallel course yourself. Then it is easy. Unfortunately, less an less possible as more and more escorts have radar, and you can get close enough to the convoy. This method can only be used if you are on the surface.

Once you have to submerge, determining speed through change in bearing is much more complicated I thingk.

Hmmm. I know tankers used it to find range up to the Korean War, when they introduced the collateral rangefinder.

The Uboat Commanders Handbook stresses time after time the importance of being able to estimate range, and the same thing is found in U.S Army military manuals today.

I have found very little anecdotal evidense to say exactly how kaleuns did or didn't do it, but nothing else really makes much sense.

Hmm.

If you can get instantaneous range through MILS at PD, then you can use the 3m15s rule to estimate speed. Then yer fine. I think.

Also, I haven't set range on TDC - I thought that was only to give you the timer till impact...

Kb

I'm a fan of this tip in getting range in rough seas.

Heibges, I think you mean AoB of 90° if you mean perpendicular, like crossing the "T". AoB 0° = down the throat and AoB 180° = up the kilt.

jmr, thats an excellent table. I use a variance of that table by plugging in the ships length instead of masthead height (MHH) during choppy wx. Even tho the ship's bouncing around, it's length stays stable; but, the measurement must be taken when the AOB is between 60-120°. You don't have to be spot-on accurate.

Cheers,

You know what - i've decided to fix my periscope/UZO. I like manual targetting, but damn - it's a bit far fetched to go to all these measures when we can just fix the damn thing; it can't have been this hard in real life! Imagine an RL Kaleun clickin' and cursin'. Not likely.

Thanks for all the help boys.

Kb