Real Navigation Mod

Read the whole thread, lots of info and problems. Check this post for updated links (22.06.2007).

This compilation fixes all (?) the bugs from Kaleun Freddies compilation. It's GWX 1.03 ready, optimized for 1024x768. See readme inside.

realnav.zip 1.01
realnava.zip 1.01 (Assisted)

Check out original thread by K. Freddie containing links to star maps, sunrise/set tables and nav help:

http://www.subsim.com/radioroom/showthread.php?t=113975
http://www.subsim.com/radioroom/showthread.php?t=114812

Clean and simple Wiki explanation of navigation basics:

http://en.wikipedia.org/wiki/Celestial_navigation

Great world map with precise long/lats. Thanks to it now I have a more or less scheme for a specific zoom level of SH3 map. Good start to make precise maps of important areas.

http://encarta.msn.com/encnet/featur...enter/map.aspx

My navigation from recent patrol. It was quite good, my error was less then 10km. Couldn't see the stars because of heavy overcast all the time... As we now know, the sea was calm so the boat was on course all the time.

[ichso]

I've got one little question for this mod too:
Sailing around by real navigation methods sounds fine but how do you gonna make your contact plottings when engaging something ?
Marking a ship's position on the map is always relative to your own position, how would you get a relatively precise drawing if you don't know even your own position that precisely ? And without exact contact markings you cannot estimate it's course and speed.
The only thing I could image to get around this is to make a full stop, estimate some fix point as close to your real position as possible and do your observings only from that point.

Or aren't 'Real Navigation' attacking anything ?

gb, i.

@Hadrys: Nice drawings btw

Originally Posted by ichso

Marking a ship's position on the map is always relative to your own position, how would you get a relatively precise drawing if you don't know even your own position that precisely ? And without exact contact markings you cannot estimate it's course and speed.
The only thing I could image to get around this is to make a full stop, estimate some fix point as close to your real position as possible and do your observings only from that point.

This is the real deal! As you just wrote it has to be relative (and was!?). I had only a chance to attack 3 ships and try to figure out some escorts during that patrol and it wasn't a big problem. If you have a brief chance of visual contact that's easy from than.

I suppose there are two methods. You can plot from your current position but that would mess things up. More reasonable I think, is to mark your last position, time and course than just start plotting your target on a clear piece of map, co you could include small course adjustments. Than after attack you could peacefully recreate your position, back on course and proceed with normal navigation. Making notes is crucial. In general I suppose it looks very scary but after just one short patrol my perception of space, directions, bearings etc is way better. It becomes natural! Don't count on sinking every ship but now it's as hard as it should be and the satisfaction is enormous!

To be honest, we should have some help, that's what our crew's for right...? but I have no idea how it could be simulated accordingly, their mistakes, their consultations with Her Kaleun etc.

[ichso]

So you draw the contact's position from the postion/course drawings you did for your own sub ? If you make little mistakes there, which would be natural, doesn't that flaw the whole attack solution in the end ? Or am I just don't getting something here ?

Originally Posted by ichso

So you draw the contact's position from the postion/course drawings you did for your own sub ? If you make little mistakes there, which would be natural, doesn't that flaw the whole attack solution in the end ? Or am I just don't getting something here ?

But that's the point! As I've wrote, sometimes it's not good or clear to draw from normal course but if I have very far hydro contacts and don't want to change my course yet I just draw distant lines from my actual course with different length representing the sound level and for example 2 km away from my course line.

It looks like you're overthinking it! Install this mod and see for yourself, it's gonna make you to search many different solutions and approaches which all end up very obvious

[ichso]

I wanted to test this mod anyway, sounds really interesting. There will be always something to do, no more 2 weeks just waiting for something to happen .
When I return from my current patrol, I will make a backup of my savegames (in case I mess everything up by accidently sailing to south africa ) and install it.

Do you need images of real starmaps or is it enough to find e.g. the polar star and then use the sextant readings ?

[joegrundman]

Originally Posted by ichso

Marking a ship's position on the map is always relative to your own position, how would you get a relatively precise drawing if you don't know even your own position that precisely ? And without exact contact markings you cannot estimate it's course and speed.

You said it, it's relative to your own position, not absolute, therefore you do not need to know your own absolute position.

It was one hour before midnight, we were only 18 hours from Wilhelmshaven heading WNW and already struggling stormy waves of North Sea. Thank God it wasn't raining, the wind was enough frustrating but somehow the sky was clear! It was probably our last chance to pick up the Polaris so I've yelled down the tower for Walter to bring his toys with him.

Like a true pro, he stated that we're way off course which was undoubtedly confirmed by main compass... damn you Walter. Not a good way to begin our patrol...

----------

OK the point is I've located the Polaris, sextant shows about 54N degrees. This would more or less match with my tiny knowledge. But how to use it precisely? I have no idea about sunset/rise times and how to use that table. Freddie mentions problem with GMT time east of Greenwich.

But the biggest problem so far is getting of the course! It didn't happened last time and if it was marginal. My errors were rather from not too exact drawing and making turns on time. The wind is 12 m/s coming from 126, sea is heavy, boat fights the waves. What does 126 mean? Is it bearing or wind course? If this is course than it should blow from my starboard as I'm going 294 but boat turns about 10 degrees north to 305 every 30 minutes. Can't help it by setting course in different ways, commanding rudder amidships... maybe I should put 1 degree port to compensate? This is getting interesting. As if I wouldn't use ctrl+click I would finish completely lost in the middle of North Sea

Another idea, I'll try going into different directions and see what happens than!?

[ichso]

As far as I know, the wind direction gices teh direction from where it comes. So if you're haeding 000° and wind direction is told as 90° then you're going to drift in west direction.
Seems like some further tests are needed to get used with the subs behaviour in the different weather conditions

Originally Posted by ichso

As far as I know, the wind direction gices teh direction from where it comes. So if you're haeding 000° and wind direction is told as 90° then you're going to drift in west direction.
Seems like some further tests are needed to get used with the subs behaviour in the different weather conditions

This would make sense - der Wind kommt aus xxx simply means its heading. Don't know why but going N, E, S for 1 hour gave just 1 degree (how do U put degree symbol?) of course change each time and now it's 15 m/s from 225. Going back for 284 gave 7 deg north after an hour... the Brits defend themselves from heading for Scapa?

[looney]

No Idea on the manual charting, but degree symbol: ALT+0176

Ok, I've done some homework.

First there was no automated system on u-boats, everything had to be plotted by the Stauerman so probably getting a bit lost off course in bad weather was a normal thing.

I've found a great world map Encarta which has superb quality, lots of names, even depths but most importantly precise longs/lats! After a while comparing places accordingly to SH3 map and prime meridian (blue) I've managed to make a photoshop template with long/lats for a specific SH3 zoom level. Take some time to see if it fits to the rest.

Below is an example of what kind of maps I'm thinking about. Precise maps of important areas with lots of geographical names to keep it more real/fun. You can photoprint them, store them on another PC? (I'm using an old laptop). With manual plotting you have enough time to compare different maps, think where to go and what to do next! Also you can put in your patrol log - "after going 5 hours at 284° we finally saw a tiny "Fair Island" on the horizon, a perfect place for an ambush".

Also my previous observation of Polaris confirms my position quite exactly. It was an hour before 00:00 (by that time there was 0 visibility) but the error should be small. Don't have a clue about longitudes yet... help!

I've encountered a serious problem. I'll try to contact Val but probably he's stuck at the same point.

I've finally figured it out how to obtain long having lat and sunset time. First of all I've made lat measure at noon and it has 20 minutes accuracy which gives 37km error (measured 53°30N, real 55°50N). Quite good for a total rookie.

3 hrs earlier I've noticed sunset time and here's the big problem. It doesn't fit anyhow using Vans almanac. The reading should be 15 minutes before sunset in Greenwich to give my current position which is about 3°50E (-15/4=3°40E). Sunset reading was way out of scale giving +59' difference so we should be 15°W!!

Till now I've observed that from the prime meridian to my current position SH3 shows 468km but Google Earth shows 250 km what gives exactly my 3°50E (1°E/W at 55°N is 62.8km - there is a simple formula for that...). Also the long and lats are equal distance on SH3 map while there should be a disproportion of 1°E/W * ~1.77 = 1° lat in kilometers (at this 55N point). Also 468/250 and you get nearly 1.77.

With above conclusion I went straight W and than N each time @ 10kt for 6 hrs to make 111.12km=1°N. I've made 114km with the sea dead flat so the error is very acceptable depending on varying speed probably. But the problem is that I've made 1°W and 1°N as looking at the map while I should really make 1°46W...

I suppose it ruins the longitude thing and can't be fixed while the whole gameplay coordinates would mess up...

Any ideas? HELP!?

Either way I'm gonna buy KM Sextant some time and hit the Baltic Sea with my also considered as not completely normal friend. I wonder where we finish without looking at GPS

[don1reed]

Hadrys,

Do you have a mod that puts those crisp LAT LONG lines on SH3 Chart?

-...-

Make sure before you buy that KM sextant that you have a professional optics man check it over. The pro will be able to tell if its been dropped or out of serious alignment.

If its in good shape your accuracy at sea should be within 0.1 m.o.a. if the mfg was CASSENS & PLATH or Freiburger.

edit: btw, if any of you gentlemen have a current or old Nautical Almanac lying about, the SR/SS LAN tables on the righthand pages don't change from year to year and can be used.

Best of Luck,

Originally Posted by don1reed

Hadrys,

Do you have a mod that puts those crisp LAT LONG lines on SH3 Chart?

Make sure before you buy that KM sextant that you have a professional optics man check it over. The pro will be able to tell if its been dropped or out of serious alignment.

Nope cause I don't understand this RAW format... either way it's useless now. I suppose that we should forget about getting proper longitudes.

About KM stuff - I have lot's of time to collect those few desired items, build that 100+ cm VIIc model with brass details, dive deeper, go further etc but thx for the tip! I'll sure do that.