View Full Version : Lame position reports

06-29-2009, 09:18 AM
Something that has bugged me about the SH series are the position reports for potential targets.

Particularly the speed and direction of the target. I don't think speed was stated as fast or slow, but instead an actual speed was given. As far as the direction was given, acual numerical values were given as estimates..

Also, it seems most if not all reports I get are so far away from my boat, that interception is next to impossible. Anyone know the file to change to alleviate this problem?

Sailor Steve
06-29-2009, 10:01 AM
As for speed and direction, I think most reports sent to u-boats were based on one of three factors:

1) Radio intercepts. If a ship sent a message and OKM managed to intercept it, it might contain the sending ship's speed and direction, or it might give nothing more than location, or it might give nothing at all and the order to the nearest u-boats would be based on rough triangulation.

2) Aircraft. If a FW-200 were to sight a ship, then speed and direction are going to be general at best.

3) U-boat. A u-boat wouldn't give a single-ship report until after it sank the ship, so contact reports are limited to convoys, in which case the information would almost certainly contain the precise information you want.

My original thinking was that you were wrong and contact reports should only be general, but after laying it out in print I'm wondering if contact reports we recieve should be more or less detailed depending upon the source - some precise and some quite vague, with the source listed.

I also think they either shouldn't appear on the map, but we should have the ability to write in that information ourselves, or they should only appear as a small mark, but with the information written by the mark with the details as they are known to us.

Of course I'm also a big fan of the 'Assisted Plotting Mod' for SH3, which leaves off even the ships you can see unless you specifically mark them, at which time the info does appear, but only for the ship you are looking at.

06-29-2009, 10:05 AM
Reading about the wolf packs in the Pacific, the trailing boat would have a a very accurate direction and speed as a result of trailing the targets. Sure, I would venture to guess a lot of reports were not dead on accurate in other instances as Steve describes. I'm not sure if the game can give 'shady' information concerning targets, etc.

06-29-2009, 10:13 AM
In data/cfg/contact.cfg is defined the range around your sub inwhich those contacts of opportunity are reported. The default Sh4 value is significantly larger (1000km) than what Sh3 had (250km or so). Probably because the Pacific is a tad bigger than the Atlantic. Personally I would rather have the choice to intercept them, than it being made for me.

In Sh3 I don't intercept targets if I can't reach them before they have trafeled 175km. That is the range where my best sensor (hydrophone range: 34km radius ) still fits in between the 'possible course' wedge (11.25 degrees either side). For a contact with a speed at the upper limit of his speed range, 7.5 knots for slow (in SH3 but the Sh4 files doesn't seem to be different in this), it means I have upto 12 and a half hours before his uncertain course allows him to escape my sensor range. Since US subs can max out at roughly 21 knots (German type 7 at about 17-18 knots) you can cross more water in the same time.

I don't know what the best sensor range is in Sh4 so I can't judge what should be possible to do. But I hope to find out soon as I have a better pc that could run Sh4 (I hope). It makes a big difference where you are in relation to his course. If you are in front the opposing speeds allows you to be further away than if you are chasing him. Then the difference in speed determines the range where you can catch him. To me that 1000km area sounds reasonable.

As for the course uncertainty. I don't know what was custommary in the real world. But I suspect it wasn't easy to judge course by patrol aircraft so high up there. Wether it was stated as a number or as a NNE, SWW etc. is moot in my opinion. It just means the same and signifies the course had some uncertainty. A given number could give the false impression of accuracy.

06-29-2009, 10:18 AM
I'm reading "U-boat War" by Bucheim and he remarks that Willenbrock (captain of U-96) said that air reports of ships and convoys were all but useless as they had no way of accurately estimating speed and that position was based on dead reckoning.

So in many cases we're getting more and more accurate information than U-boat commanders got.

I'm sure someone who's more familiar with the Fleet boat side of things will be along to share how things were done on that side of the war.

Sailor Steve
06-29-2009, 10:21 AM
Not me. I have mine set to not give a single-ship report more than 100 km away, and convoys no more that 500 km.

06-29-2009, 10:35 AM
I think the problem is the misconception that these reports are for you. They were mostly sent for all boats deployed. If you have a chance for interception, go for it. Otherwise ignore it.


06-29-2009, 05:22 PM
If I ignore them, I just end up with one empty patrol after another.

06-29-2009, 05:42 PM
If I ignore them, I just end up with one empty patrol after another.

Its the best plan... ignore em' if they are too far away.

06-29-2009, 07:01 PM
This is a tutorial from Ducimus on postion reports and what you can do even if you think you are a million miles away from doing anything at all. This is the use of the map in the TMO mod created by Ducimus.

lets say the little X i drew is a contact report on a convoy that is moving at 9 kts and heading NE. So the first thing you do is pull down your chart to see how far he can travel at that speed, and how long it will take him. According to this handy dandy chart, a target moving at 9 kits can travel almost 72 NM in 8 hours. So i just used that since im a bit a ways from him.


Here i drew my circle, and faced it NE, same course as the convoy, and 72NM wide, centered on his current position. In 8 hours, assuming no radical changes in course, he should be somwhere where the line intercets the circumference of the circle. Not exact, but in that general vacinity. So now, i know where he will be, which is alot more important then where he currently is, if i plan to intercept him.

But how long will it take me to get there, and how fast would i have to go to be able to intercept him? Will i make it to that area in time? Is it possible to intercept him, or is this a fuel burning wild goose chase?

Time to go back to the chart:

Since im plotting on an 8 hour time frame, ill use the same for myself. Going at 19 kts, i can cover a distance 152NM. So lets plot that out.

So here's an 8 hour plot. Where i could be in 8 hours, and where he could be in 8 hours based on my projected speed of 19 kts, and his current speed of 9 kts. Now, really, i'll probably be pushing 20 to 21 kts, so i'll acutally cover this a bit faster.

In short, here is a contact report that i can get a firing position on, but barely. Now if this contacts speed was report at 12 kits, or somethign higher, this plot would have come out differently, and i'd probably have decided not to chase it and conserve my fuel. But in this case, it might be worth the fuel expenditure because we know we can overtake him if we want.

06-29-2009, 07:29 PM
The problem I am having is the fact all of the reports I get are very far away. I never receive one that is even in my grid.

06-29-2009, 07:59 PM
The problem I am having is the fact all of the reports I get are very far away. I never receive one that is even in my grid.

Give it time. Are you using any mod packs at all?

06-30-2009, 10:07 AM
It also depends on where you are ofcourse. If you are in the middle of nowhere!? There must be waypoints scripted for a unit in that area if it is to produce a contact report. And it should also have a sufficiently high random probabilty assigned for it to make itself shown. But I'm sure that is the case.

06-30-2009, 12:22 PM
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