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There might be a reason from time to time to give up a target for the moment. Before I leave I mark its current position and heading.
I might also mark a bearing to a sound contact if I have more than one and is chasing after one and is afraif of loosing two since he is very far away, then I mark his bearing bfore giving chase to one.
Then ofcourse you draw lines between ports and make different plots to aid in guessing where to intercept reported convoys.
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Okay, i was bored so i whipped up a little tutorial on my method of using the map for plotting a target's course without God's Eye View. It's for patch version 1.4b because this version added a crucial tool to the map screen.
I do this step by step so please bear with me if i should tell you things you already know. I wanted to cover the basics thoroughly. I also provided screenshots, so please click on the thumbnails to enlarge the images.
Here we go:
Okay, first of all make sure that your boat doesn't move. The rudders have to be locked on zero. You CAN do this kind of data collecting while travelling (straight ahead), but the data is going to be more accurate when you're stationary. Now to the procedure:
1. Visually locate your target, lock it with your periscope/UZO and identify it. This is important because we (the notepad that is) need to know the mast height of the target.
2. Now we need to find out the distance and the direction of the target. Click on "Entfernung/Range" on the notepad in the upper right. Align the horizontal line of the periscope crosshair with the waterline of the target. Now click on the round symbol in the lower left of the "range"-page on the notepad. A second horizontal line will appear in the periscope. Align this line with the top of the highest mast of the target, while making sure that the first line stays on it's waterline. Bobbing in the waves is a factor here.
Once both lines are in proper position, click and you have the distance (in this case 1635 meters). Read the angle of the target in the periscope (here about 152â?), and you have the data you need.
3. Memorize this data and head for the map screen (F5). Now you need to select the "Winkelmesser" or "Protractor". This tool was added in version 1.4b, i think, and is very important for the steps to follow.
4. With this protractor draw a first line from the bow (my boat's bow was facing north) to the stern of your boat on the map, then use the second line to determine the angle of the target in relation to your bow. The arrowhead of the first line should point into the direction of your boats bow, the second line's arrowhead should point into the direction of your target. Here's something important to know: while the angle on the pericope is measured in a full clockwise 360â? circle, the protractor works differently. It only measures from 0â? to 180â?, either on starboard(right) or port(left), as it is supposed to measure the AOB (Angle On Bow). In our case the periscope told us that the target was on 152â?. Periscope numbers from 1â?to 179â? are on starboard wile numbers from 181â? to 359â? are on port. So you need to use the 2nd line of the protractor to draw a 152â? angle on the right side of your boat. It should look like this when you're done:
5. Now that we know the direction of the target, we need to add the range. For this purpose you use the "Lineal" or "Ruler" tool.
Now draw a line from the center of the two protractor lines (which should be somewhere within the confines of your boat if you stayed stationary), align it with the second line of the protractor and make it long enough until the number on the end of the line is close to the measured distance of the target.
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6. Now you take the "Stift" or "Pen" and mark the end of the line. Congratulations, you just took your first position reading without God's Eye View.
7. Naturally we need more than one position reading in order to determine the target's course. That's why we're gonna take at least another one after some time has passed and the target has moved a bit. The time you wait between readings is not that important. Just make sure you wait long enough so that there is enough distance between two position readings, because the greater the distance between two spots the more accurately you can determine the course. The pros usually waited 3 minutes and 15 seconds before taking another reading.
8. After enough time has passed, take this new reading, using the same steps as before: measure the distance with the notepad, read the angle of the periscope and mark them down on the map. If your boat hasn't moved you can reuse the protractor and ruler lines that are already on the map. Just select the corresponding tools, grab the ends of the lines and drag them to the new position.
9. Good. Just to make sure you can take a 3rd reading, or even more, if you want to. The more readings the more accurate the determination of the course. In my example the target has moved to my port(left) side now (220â?) so you need to find out the AOB for port. This is easy: just subtract the periscope angle (220â?) from the full circle (360â?) and you have the AOB for port. 360 - 220 = 140â?. Use that number on the protractor and proceed as before.
10. When you think you have collected enough data, all you have to do now is to use the ruler tool, connect the marked positions on the map and extend the line into the target's travelling direction as far as you want. Now you know the target's course without God's Eye View.
Now you can plot an intercept course for an almost perfect perpendicular firing position and sink the sucker.
You can also use this method to determine the course of a ship without visual contact and via the hydrophone. Of course you can't take accurate distance readings that way because you have to guess the distance based on the volume of the sounds. But it's good enough to give you a rough idea as to where a detected ship is going and to get close enough to use the visual method after all.
I hope this little tutorial was comprehensible and helpful.
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I do my calculations on the way to my intercept point. I parallel my course and speed with the ship at bearing +-90%, and monitor it's distance from the WO. Minor course adjustments until the distance is fairly constant.
I then mark its position and use the Linear ruler (mine has a protractor on it) and plot it's course, then off I go to the intercept point.
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Not a problem... you're welcome!Originally posted by U734:
Thx very much to all of you and especially NaturalBornGoth
No, not necessarily. Of course the faster your target is the less time you need to let pass between readings. It depends on your standards concerning accuracy. The closer the two read positions the higher the error margin when you extrapolate the ship's course beyond those two points.Originally posted by U734:
And I have 1 question: if my target moves with ~8> knots speed (more than my underwater speed) isn't there a possibility that he just slips away until I make several readings?
And this i have to add as well: i used a situation from the torp training in the naval academy. The target was already in a perfect firing position, so in fact plotting the target's course in this situation wasn't necessary at all. That's the problem with examples. During a campaign you would use this method on targets that are farther away and in a lot odder angles than in the used situation.
To make a long story short: enemy ship's usually don't travel that far between readings. The distance between my 2nd and 3rd reading only was that big because i wanted to make a point regarding the protractor angles.So in a "real" combat situation the ship won't slip away, because ideally the course plotting should be complete before the target is passing you by. You also use this method in situations when you spotted a target that already IS moving away from you. In situations like that you need to determine the course in order to catch up outside it's visual range and intercept.
Hm... that would come in handy. I need to get myself one of those. You wouldn't happen to have a link for a ruler mod like that?Originally posted by vanjast:
...and use the Linear ruler (mine has a protractor on it)
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Yes, I'd like to add my thanks to NaturalBornGoth. That was a really comprehensive tutorial. You should add it to the Community Manual!
The only thing that I'd add to it, would be that whenever you take a distance/course reading, make a note of the time. Then, on a piece of paper, write down the Mark/Markierung number and the time associated with it. That way, you can later use the Nomograph to determine the speed at which your target it going.
While in priniciple, you can use the "speed" tool on the Notepad, having a backup is often a good idea.
