Estimating course at long range

[Petr]

Is there any possibility to estimate course and speed at long range when you can t recognize the ship. I play with german U boot so I can t use sonar. Do you have any tip?

[gordonmull]

Close till you're at a better range. Probably not much help but that's how I do it!

[Jaeger]

Originally Posted by Petr

Is there any possibility to estimate course and speed at long range when you can t recognize the ship. I play with german U boot so I can t use sonar. Do you have any tip?

german kaleuns did this by trying to hold a parallel course. try to bring the target to 90 or 270 degrees and look at the distance. change your course and speed until the distance stays equal.

[Petr]

but problem is, that I don t know range. I play 100%.

[DarkFish]

You don't have to know the exact range for jaegers method, just count the number of pixels above the horizon and take that as range. So adjust course and speed till the ship's height in pixels stays equal.

[Indy676]

normaly with "v" or "Strg + v" the oow will tell you the bearing and range to the nearest target. Put this on your nav-chart. Do it some minutes later again, and you can see the course on your chart and you can compute the speed. Take 6 min and you have the ten's part of the distance the ship will travel in an houre.
The only thing you have to do now is to compute the km in nm.
Hope I could help you.
Greets Indy

[Jaeger]

Originally Posted by Petr

but problem is, that I don t know range. I play 100%.

in former times, german kaleuns were able to get a good range measurement up to the horizont. so it is, as mentioned before, not unrealistic to ask the WO i think (for me, it is a little bit too accurate, but i am not quite sure about the accuracy of theese gears. i think hitman can help about this). also the pixel size is a good info about range. best results you can get if you go as close as possible (without detection of course)

[Indy676]

All right, it is a little bit to accurate. But to estimate the range in SH is much more difficult than in real live. I’ve been to sea for a couple of years, and I had no problems to estimate the range of a ship near the horizon to as accurate as half a nautical mile and less with a visibility of 15 nm. But fortunately I could verify the range with radar, and that is a good way, to learn estimating the range of ships.
Greets Indy

[Fisherman]

Method I use is to drive my boat at flank speed directly toward the target. If the target drifts to my right then her course is towards my right, and likewise if target drifts to the left then she is heading to my left. Once you know which direction the target is heading turn your boat 60 degrees in that direction and you will be on an approximate intercept course (this is called the approach phase). Once ahead of the target and normally submerged you then take the range, speed and AOB to fine tune your position and set up the torpedos (called the attack phase). Got this tip from a fleet boat manual, posted in a Rockin Robbins ( ) thread here: http://www.subsim.com/radioroom/showthread.php?t=146795 Hope this helps.

[don1reed]

@ Petr:

Nice to see that you are playing @100%.

Although History tells us that the “Greatest Generation” did not use any electronic tools to determine distance (entfernung); save PPI radar, late war, Allies.

Pre-radar and later, to avoid their own radar signature from detection, US Submariners used the “High-Scope” method, where the scope was raised to full height while surfaced to see targets beyond the horizon. In fact, this “high-scope” was modeled in the original Silent Hunter. Alas, it is not used now; and, Kriegsmarine doctrine did not allow for the use of the highscope method. (Uboot Commander’s Handbook.)

What they did have, however, was their state-of-the-art optics and mathematics:

Ref: “The American Practical Navigator” a.k.a. “Bowditch” (Free copy on the web via Google) demonstrates in Table #12. Distance of the Horizon-

Distance in n.m. = 2.12 √ height of your eye asl* in meters. *asl = above sea level.
note: if using height in feet, make the constant 1.169 instead of 2.12.

Ref: “Bowditch” Table 15. Distance by Vertical Angle Measured Between Sea Horizon and Top of Object Beyond Sea Horizon-

They used their sextant to measure these small fractions of angles; and apply corrections due to refraction etc.; however, this brings us up to date of how we, as players can estimate long distance target ranges and thereby, plot their courses.

When a target ship is hull-down, you can estimate it’s masthead height (MHH) as 100 feet or 30.48 m...apply the Distance of the Horizon formula, above, for the target’s perspective, add the results to your own distance to the horizon and you will have your answer for plotting.

Cheers,