targeting: what am i likely doing wrong?

[old1]

I *think* I'm up to speed on all the concepts of targeting (playing 100% realism with RFB+RSRD), and in fact, I've sunk some amount of merchant shipping, so I'm doing something *sorta* right. I've watched tutorial videos and read a lot of online stuff, so I should have a basic idea of what's up by now.

But the following happens to me with annoying frequency. The last time was like this: I tracked a large-ish (~7000 ton) merchant boat going 10 knots. I know he's going 10 knots, because (a) I paralleled him for half an hour, and (b) on getting close, I measured his distance over 3 minutes. I'm about 98% sure I've nailed his speed. I establish a track on the TDC about 4000 yards out (measure AoB, etc) and refine it a little as he gets closer. The track seems to be good: he's always right where the TDC predicts and the AoB in the TDC seems good. I launch at about 1000 yards, three torps, with a +2/0/-2 spread (I'm trying to avoid a 90deg impact angle of course). All three torps pass in front of him by about half a boat length. Ack!

By this time he's perpendicular to me on a 0deg relative bearing around 700 yards out, so I quickly reset AoB to 90deg and launch the other three tubes. He still has apparently not detected me. A bit of a stern chase now, but once again all three pass in front of him by around 1/3 or 1/2 a boat. Grrr!!

It makes sense if I'd got his speed wrong, but I'm pretty dang sure I didn't. Anyway, say I missed by 2 knots - that's only 100 feet difference or so in his position, and he's way longer than that. I'm also pretty sure he didn't detect me: he didn't manoeuvre at all, and I hardly had the scope up at all inside 2K yards - maybe 3 or 4 seconds total.

I had a similar issue earlier: I found a large modern composite, similar scenario to the above except that one managed to hit him *right* at his bow. The other two missed.

I can't figure out what I'm doing wrong. Range estimation maybe? But inside 1500 yards, the stadiometer is agreeing with the sonar range really closely - within yards. And as I said, I'm pretty sure I nailed his speed too. Which leaves AoB, but that seemed OK and anyway shouldn't be super critical once it's set inside 1500 yards as long as the TDC track is good, as it appeared to be.

I just can't figure out why I'm missing from such close range. I have enough problems hitting stuff inside 1000 yards that I can't even fathom needing the slow speed/long range setting on the torpedoes. My chance of a hit from over 2K yards is probably around zero.

*Edit* A bit of other data I forgot to post: If I recall right, the gyro angle was something like (roughy) 30 deg. I was aligned perpendicular with the target course, and he'd pass about 680 yards from me, and I'm using the fast torpedo setting.

[magic452]

Are you playing stock or mods, 1.4 or 1.5????


Magic

[Rockin Robbins]

Magic has it right. We need to know what manner of beast you are playing and we can figure it out.

[gutted]

that's strange.. most people having problems tend to have the torpedoes missing behind the target.

usually due to not opening the tubes beforehand and/or not geting an updated range/bearing immediately before firing.

[gutted]

i tend to use metric but 680 yards does seem abit close for a 30 degree gyro angle. that could be your problem right there. but that also begs the question of... why are you firing with a 30 degree gyro angle to begin with if you have the time to wait for a 5 or 10 degree gyro? the more gyro the less accurate.

maybe someone else could chime in, but whats the inital torpedo run (in yards) before the torpedo makes its turn?


also... a +2/0/-2 spread is abit wide imo. i rarely go over +/- 1 degree. usually its +/- .5 degree.

but thats just my two cents.

[magic452]

Gutted that is what makes this so strange a +2/0/-2 at 1000 yards all going in front?????? and than 3 more at 700 doing the same thing.

He seems pretty sure of the target speed and that is about the only thing I can think of.

the straight run is about 4 to 500 yards I think? Edit that seems to be more like 2 to 300 yards.

Magic

[old1]

Thanks for the replies - I'll try to answer the questions.

It's game version 1.5 + RFB + RSRD, on 100% realism.

'Why a 30deg gyro angle' - well, given the geometry of the situation, if I shoot at 0 or 5 deg gyro it'll make the angle of torpedo impact with the hull closer to 90deg, which I'm trying to avoid because of the famous dud problem. I was going for something more like a 'several tens of degrees off perpendicular' impact.

'Why -2/0/+2 spread'; - mostly because I've been missing a lot, and I wanted to give a big spread to increase my chances of *something* hitting :-/

But I have a theory - I'm not sure yet if it's true and I'll not have time to check it before this weekend. But here's the thing. At close ranges (inside 3K yards maybe) I'm using the stadiometer as my primary range tool. I believed my estimated track was right because I could put the scope down, wait a minute, pop the scope up and see the target right where predicted, both bearing and distance (to within a few yards). But here's the thing. The recognition manual has these red bars at the top of smokestacks, and I've been using that as the reference height. (Not sure if they're from the stock game or one of the mods). But when I've watched tutorial videos on youtube, the person always uses the *mast* or rigging height - basically the tallest point on the boat. The stack is often lower than the tallest mast.

Check my thinking here: if I'm using too low a point, that means the target is closer than I think it is. So my torpedoes will swim out in front of the target because they they're heading for an impact further out.

One reason I'm not sure about it is that I've seen a good match between the stadiometer distance and the sonar distance. Now I know the sonar can have a large error, but at close ranges it seems *pretty* good, and certainly not 20 or 30 percent inaccuracy.

Anyway, is my assumption wrong that I should be using the part of the structure marked with a red line in the recognition manual? Or should I rather be using the very top part of the mast or rigging? Sometimes the masts can be hard to see from a distance, so I had assumed they picked the easier to see smokestack instead. Maybe this could be my problem? Some ships have a big difference between the two heights. It could be a large range error, yet everything *else* would look fine, because when I check the range against TDC predictions, I'm using the same (flawed?) method.

[DigitalAura]

actually, I think you ARE supposed to use the red marks on the stack where indicated in the Recog. Manual.
So... that's shoots that theory down..

[sergei]

Hmmmm
Something springs to mind.

I'm not running RFB at the moment but when I did I don't remember it having red marks in the recognition manual telling you where to range from.

Is it possible you tried another MOD before RFB, eg. SCAF or TMO, both of which do use the red lines, and either of those is still installed, thereby screwing up your range estimation?

At the moment that is all I can think of for your problem.

[sergei]

Yep - just enabled RFB 1.52, checked out the recognition manual, NO red lines telling you where to range from.

From page 39 of the RFB manual:
" Determining the Correct Distance Measure Reference Point
In order to reduce confusion while remaining true to the dat apresented in the ONI manuals, the following reference points are used for each class of ship. . . .
Merchant Ships: Top of the tallest mast
Aircraft Carriers: Flight Deck
All other warships: Top of the tallest funnel"

Just to re-iterate: RFB recog manual does not have red marks in it, other mods eg. TMO and SCAF do.

I'm guessing you may have a case of MOD SOUP going on here. Did you try out TMO or SCAF before settling on RFB? If you did, the recog manual change bit of the previous mod may still be enabled. That could screw up your range reading, and therefore screw up your shot.

You are quite rightly not going for a dead 90 shot to reduce the chance of duds, but because it is not a zero gyro angle shot an accurate range estimate is required.

Reading about your problem I would normally say that your speed estimate is wrong ( that will FUBAR your solution every time!), but you seem so sure that your speed estimate is right that this is the only explanation I can come up with.

Anyone else any ideas about this fellas problems? This is the only explanation I can come up with.

[gutted]

likely the problem.

the larger the gyro angle, the more important the range to the target needs to be (at 0 gyro, range doesn't matter at all.). Also the further the range, the less actual gyro is needed to hit the target. two targets at 20 degrees periscope, will require different gyro angles if one is at 1000m, and one is at 4000m. ofcourse this would mostly only apply if they were moving. the torpedo going for the further ship will take longer to get there, and needs to lead the ship further.. and hence less gyro.

so if the ship is actually closer than what the PK thinks it is (your problem)... then you aren't getting enough gyro. the torpedos pass in front of him to hit the imaginary ship the PK is tracking further away.

try turning on map contacts for a mission (or two), to check that you are getting good stadimeter readings. if you are way off, then you are using the wrong parts of the target to use the stadimeter on.

[sergei]

Another idea
Try the Dick O Kane targeting method
Requires no stadimeter range finding
I've been using this method for a year works every time
http://www.subsim.com/radioroom/show...6&postcount=67
Let us know how you get on

[old1]

Sergei and Gutted - thanks, this is getting rather suspicious. I'm using RFB 1.5, not 1.52, because I had some CTD issues with 1.52 while 1.5 was quite solid. I wonder if there's a difference there. I've never installed TMO or anything besides those two mods (RFB+RSRDC), and I only installed it several days ago.

This info that Sergei found is particularly interesting:

In order to reduce confusion while remaining true to the dat apresented in the ONI manuals, the following reference points are used for each class of ship....

Because if that's how RFB 1.5 is behaving (no matter what red bars I see), then it would totally explain my misses in front on merchant ships. I'll investigate that this weekend and report back.

TexanInSoFL: The way I've been setting AoB is as follows: I plot the target position and track. Then on the map, I use the angle measuring tool to measure the angle between two vectors: (a) my boat to the target and (2) target along his track. At long ranges it's often a small angle, like 5 or 10 degrees, so I refine it as the target passes inside 2K yards or so. I manually input this number to the TDC. So far it seems to produce reasonable results, but then again, I do miss a lot for *some* reason...

[gutted]

if you know the targets course.. setting AOB is trivial.

just set the AOB dial to what it looks like at that scope bearing, and send it. then look at where the 0 on the target's "inner" dial is pointing at on the outer dial. it should be pointing at the target's course. (note: you need to send atleat one range/bearing before mucking with it's AOB)

so say you know the target is on a true course of 200 degrees. when you set the AOB the 0 on the inner dial should be pointing at 20 on the outer dial. if it's not, then adjust the AOB slightly and send it again until it's pointing at 20.

later on when the taret is closer, you may get alittle "AOB" drift when sending a new bearing/range. just adjust the AOB again until it's pointing at 20. if after multiple range/bearing readings (over a period of time) the AOB does not drift, you proably have his true course set correctly.

hope that made sense.

[magic452]

Thanks Gutted that is a neat trick I've never though of before. Will save a lot of guess work.

Magic