navigating during the attack run

[Sea Hawk]

I’ve been looking at some threads on navigation.
I can see that in the real world the sub would have navigated large distances using celestial navigation. My question is what happened in the final stages when every time he popped the periscope he risked being seen?

In the game the U-boat and the targets move about on the chart similar to a sat-nav system. I’ve managed to turn off the targets on the chart so that I have to plot them. But the U-boat still moves about like a sat-nav image.
If your U-boat is stationary then the important information is to plot the targets position relative to your self. But usually both the target and the U-boat are moving.
How did the U-boat commander know where he was on the chart? did he keep popping up the observation scope to use a sextant and so risk giving himself away during the attack run, or did he rely on dead reckoning?

[Otto Heinzmeir]

During an attack, the position of the sub relative to the nav map doesn't matter. The navigator would plot the sub course as a straight line and plot the target position relative to the straight line course of the sub.

Hitman has a plotter tool for SH4 that I pictured. We need one for SH3. hint hint.... The sub would be set at a certain speed. Say 5 knots, then every 3 or 5 minute time slot, the position of the target would be plotted. The hash markes would show the subs position after each time increment with the numbers representing the subs speed. So actually position of the sub as far as long/lat wasn't a factor in plotting an intercept.

http://img.villagephotos.com/p/2005-8/1059112/plotter.jpg

[Pisces]

...
If your U-boat is stationary then the important information is to plot the targets position relative to your self. But usually both the target and the U-boat are moving.
How did the U-boat commander know where he was on the chart? did he keep popping up the observation scope to use a sextant and so risk giving himself away during the attack run, or did he rely on dead reckoning?To keep track of where they (uboot itself) were i think he used both. Dead reckoning all the time since celestial navigation wasn't possible all the time. They could only use the sextant when the sky was clear. Whenever possible to make star/sun/moon/planet fixes they used it to correct the deadreckoning position.

As for during the attack I am quite curious also. I know there are charts and papers of uboat navigators traded as collectors items on the net. But I have never seen one for real, or an image of good quality on the net. If anybody has something to show, please do.

I'm sure their solution (uboat navigators) was to use relative measurements (bearing and range) in longterm tracking like Otto said (and Hitman makes every effort to find out the historical truth to base his mods on, or so it seems). It's all done with vector additions/subtractions you may have learned at (high)school. From that it is an mathematical issue of calculating the targets position on the globe, or just drawing it over to your dead reckoning position on the map in KriegsMarine-Grids, to perhaps radio it over to BdUHQ.

If you are curious you could read these PDFs in zipfile about radar and maneuvering techniques from the US National Geospatial Intelligence Agency. In particular chapter 3 and 6:

http://www.nga.mil/MSISiteContent/StaticFiles/NAV_PUBS/RNM/pub1310.zip