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Old 07-29-2019, 09:35 AM   #1
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Default No map contact - Target's course and range?

I recently made the big jump and started playing GWX at 100% Realism without map contact updates. I am doing somewhat okey, but it is when I spot a ship that I have some trouble.

I know that first, I must acquire the target's course, speed, and range.

I try to do so using my Watch Officer's visual contact report, which gives me a bearing and a range, usually between 7 and 8000 meters. I then use my compass to circle the range, then the protractor to pinpoint the angle between my relative bearing (0) and the target's bearing. The reason I do so is because the sub's bearing circle disappear when zooming out, so I use the angle as a marker (for example, 279 would be (360 - 279 = 81 degrees port of relative bearing 0).

Mark 1 on the map where the circumference and the angle line cross.

After waiting 3.15 minutes, I redo the sames steps, retracting the compass and updating the protractor (after recentering them both on my sub's new position, of course) to the new range and bearing.

Mark 2 on the map.

However, the target's estimated course and AOB seems always wildly different from the target's visual course. So I must be doing something wrong.

I accept that the WO's estimated range might not be exact, but still... How do you veterans proceed with visually estimating a target's first course and speed when contacts are turned off? Especially at medium and long range.

Thanks for your help and your pro-tips!
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Old 07-29-2019, 09:43 AM   #2
Sailor man
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I would suggest plotting at least half a dozen marks and then averaging the course between them. The more marks you can create, and more time you can observe, the more accurate your plot will be. If I have the luxury I will often continue to plot during the entire overhauling maneuver, resulting in dozens of marks which leave me with a very clear and accurate course. Also, don't be afraid to take them at quicker intervals than 3:15, just make sure you do get at least one or two 3:15 checks to get speed. It's worth noting you can take shorter speed observations as well as long as you multiply your result accordingly, ie making roughly 1 minute marks, then times your result by 3. Once you get the speed though, just keep observing and marking as long as possible to hone in their course and therefore ultimately AOB and range as well. Then make your intercept and you know what comes next

As an aside, it's well worth learning some basic periscope methods for obtaining speed, range and AOB, good for last second adjustments when you are very close to the attack. Also if you make the jump to SH5 and Wolves of Steel (highly recommended when you are ready for another "realism" bump), with Real Navigation you will probably more and more rely on visual observations vs plots (this due to the fact that you will need to keep track of your boat as well as their boat if you choose to plot, not impossible but perhaps impractical in many situations). Overall, my personal favorite method is the RAOBF wheel.

Last edited by abaileyatd; 07-29-2019 at 10:00 AM.
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Old 07-29-2019, 11:08 AM   #3
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So you are plotting by that big rotating bearing wheel centered on your sub? I never really liked that. 1, back in the day my pc performance suffered from it's large size. And 2, it moves while you are trying to get the plot down. So it is hard to get the bearing or range on the proper grid position.

Instead I make, or I should say made as I barely play SH3 thesedays, frequent use of some GUI tools and a physical DIY attack-disk, or handheld calculator.

At the time to plot I ask the watchofficer for a range and (relative) bearing.
Immediately I plot the start of a line where my Uboat is then. I leave the end of it in the rough vicinity of where the target could be.

To plot lines in a specific direction you need the true bearing (or heading) to the target. You can calculate it as owncourse + relative bearing. Then subtract 360 degrees if you need to get the result below 360. My physical attackdisk is used by rotating the bearing backplate to the compas scale for my course at the triangle representing own course. Then turning the bearing pointer to the relative bearing, and reading the true bearing on the compass disk. This is quickly done fractions of a second.

Now, knowing the true bearing to target and range to target I can update the end of the plot line using the bearing wheel on the mouse cursor. I made my own small mod expansion based on the OLC gui mod I had at the time. This adds the compass scales to all line tools on the map. Although GWX3 already has such a tool for the line iirc. Anyway, this tool won't disappear from the map when zoomed in. And you can take your time because you are no longer chasing a moving grid. Much better accuracy of the plot.

As I recall the default Watchofficer reported range in units of 100m. This is precise enough. Perhaps even too much. That was the reason they added some randomness to it through the HSie/Stiebler patch SH3 executable mod. If you have that applied that may also be part of the reason your plots may not be matching to the visual perceptions of AOB.

Last edited by Pisces; 08-01-2019 at 03:54 PM.
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Old 07-30-2019, 05:47 AM   #4
Andy 01288
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All of the above, and also ask your Watch Officer a few times for the range. I`m chasing down a large merch atm and he`s just told me: 11,000m/8,300m/10,000m so I`ll plot at about 9,500m.
The more plots the better...
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Old 07-31-2019, 12:40 PM   #5
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Thank you all for all the help!
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