Real Navigation with SH3

[don1reed]

Don't know if this has been tried with SH3 with any success, but Real Navigation with SH4 does work and I've got it to work with SH3 also> See Here: Beginning with Post #124 http://www.subsim.com/radioroom/show...=116170&page=7

cheers,

[Gairith]

Was a do it yourself mod out there http://www.subsim.com/radioroom/show...eal+Navigation
I used the sextant for a short time to try it out. Never went anywhere with it.

Nevermind, see you were already there awhile back.

[don1reed]

Same here, Gairith. This uses a "Python" script and "Stellarium", (both freeware) standalone pgms. While SH4 or SH3 is still running, I do a save, go to the script to input data of date/time UTC & Wx conditions then go to stellarium to get data from heavenly bodies, return to the game and at my leisure perform sight reductions and plot my position real time.

It works as in RL and performs like real navigation. Of course, if it's cloudy or foul wx I act accordingly.

cheers,

[dertien]

Hello Don,

Could you elaborate a little bit more on how you handle realnav in SH3 , what tools you use etc...

I have been looking all over the forums here, and all the information I found got me there halfway, or not at all.

Could you point us SH3 players to a link, tutorial, how to use this in SH3 ?

[don1reed]

Hey, dertien

The point man on this is, 6SJ7GT, but he hangs out on the SH4 Mods forum and doesn't play SH3, or have it....However....I do

He's created a script using "Python" which interacts with both "Stellarium" and "SH4". I've changed the script to suit my computer's filing structure ( c:\documents and settings\...etc.) so that I now got it to work with both SH4 & SH3.

I say again: Python and Stellarium are FREEWARE.

Here's what it does:

1) While your sim of choice is running (SH3 or 4) do a save of the game but continue to run it.

2) Slip out of the sim leaving it running and run the Python script and input the Date/Time (UTC) and Wind speed & boat speed--exit Python.

3) Enter "Stellarium". Python will have automatically set up Stellarium to where it displays what the real world would look like at the geo coords and date/time that you are experiencing in the game.

4) The clock continues to run in Stellarium; however, you can simulate taking sextant sights (sun/moon/planets/stars) (click on body) as it gives Hs and Az of the heavenly bodies, by pausing Stellarium after each sight.

5) 6SJ7GT has also provided ephemeral data for the war years which will allow you to do a sight reduction for your acquired data.

6) Plot your course on a real paper plotting sheet or plot it on the F5 screen.

This procedure is not meant for the casual player as it is real navigation and is as time consuming as the real thing because it is the real thing.

Beginners should try this if they keep the waypoint tool and the sub/uboat icon on. The more experience and confidence you get with it, one can stop using the icon & waypoint tools.

In order to make it work from the get go I begin my patrols with waypoints to the mouth of the harbor to give Python a point of reference. It goes into the SH3/SH4 file in Documents and looks at the locations of the saved game and converts them into Lat/Long for it's use.

Best place to start is here: http://www.subsim.com/radioroom/show...=116170&page=7

Begin with Post 124

I hope this helped.

all the best,

[don1reed]

There's been a lot of effort into making a realnav mod for SH3 with somewhat disappointing results. The combination of pgms SH3, Python & Stellarium is the most realistic to date. For one thing it will give the neophyte navigator a lesson of what it takes to move vessels around on the surface of the earth.(and below)

It will definitely take the player to a higher state of immersion. From taking sights to sight reduction, with or without weather's influence, a whole new game.

[dertien]

Thank you Don1,

This looks like a thorough tutorial, have saved all pages, and will get studying immediately.

greetings

Dertien

[don1reed]

Roger dodger, dertien

If you need any help setting up your script for SH3 give me a shout.

There is a location in Stellarium that must be changed to read "utc". Let me know when you reach that place in your new adventure.

also, make sure you begin a new career with this just for the sole purpose of ironing out any bugs.

as always, cheers.

That SH4 real nav thread is interesting. I have been using the SH3 real nav mod that's posted around here somewhere, but lacking knowledge on how to shoot stars/sun I have been relying entirely on dead reckoning! However I have successfully completed 2 patrols on dead reckoning alone so it isn't impossible.

I bookmarked the pages that looked promising.

[ichso]

So you're still into the real nav thing don1reed ?

I havn't played SH3 for a while now. I wanted to try your suggestion, but the site stellarium.org doesn't work.

Another thing: what about the stock SH3 bug that the the ranges aren't displayed correctly on the navmap ? When you travel west, lets say to longitude of 50°W then this should be a shorter way if you are further north than (for example) directly at the equator.

Doesn't this bug disturb your calculations or do you just take them into account ?

[don1reed]

Howdy, Ischo

Yep, still hangin' in there.

I have no probs with SH4. Crossed several time zones and results were rock solid.

In the middle of an SH3 patrol now, heading SWxW out of Lorient for BE86 in a typ9. I'll test that anomaly out shortly. Is there any particular Latitude were that shows up in game, or is it a fact all along the meridian 50W?

I really don't believe that it will present a problem as no matter where your boat is in the game, "Phython" looks at the geo coords of where it really is via the SH3 file in the documents section of the computer's files. The player usually has no knowledge of where his boat is in terms of geo coords as the player only sees KM grids. The game, however, is dealing with geo coords.

The name I've saved for my first patrol using this setup is "100". When I follow the directory path in my computer via the "SH3" doorway, the file name "100.map" is the one that Python uses to setup Stellarium to display what the uboat/sub sees on the F4 screen.

I'll let you know what happens.

PS stellarium.org is working now.

Cheers,

[jmr]

Don, I have several of your threads bookmarked that I use for reference as they contain pearls of information of translating real world mechanics into the virtual world of Silent Hunter. Good stuff.

So with this mod, how do you get around plotting way points without the origin of the waypoint line giving away your location? If the waypoint tool isn't used, how do you get your helmsman to hold his heading without drifting?

[ichso]

Hm, the 50° where just an example. I can't find it where I read this. Was it a dream ?
I looked through the whole GWX manual, perhaps it was in one of the real navigation threads around here, I don't know.

But I *think* I read somewhere that the SH3 map is flattened out, so that it doesn't take into account that travelling farther north (or south respectively) requires less time to cross the longitude markings.

So with this mod, how do you get around plotting way points without the origin of the waypoint line giving away your location? If the waypoint tool isn't used, how do you get your helmsman to hold his heading without drifting?

That was another thing that was bugging me some month ago when I last used real navigation.

[don1reed]

Aha, the trick, JMR, is I plot my last waypoint at the mouth of the harbor. It gives Python a reference point; all the saves of the game thereafter, supply's Python with the geographic codes (numbers that are divisible by 120,000)(don't ask me why it just does) wherever your boat is located. Its up to you the player to zero in with correct sight reductions to plot your location.

I'll show you a plot I'm doing in my present SH3 patrol as soon as I get it copied to imageshack.
edit:

Ok, here's a 3 star fix just outside of Lorient with attendant sight reductions.



cheers,

[don1reed]

oops, sorry Ischo, I apparently simul posted when you did and didn't see what you wrote.

Ok. Got it. I believe I know what you're talking about now. Yeah, this method isn't effected by that. Mercatur projection. I know it won't work if you try to sail a great circle course.

Here at least Python uses the numbers that the game produces and I'm always in the ball park. I've never been exactly spot on but that ok, I never been totally off the chart either.

So far with this method, by making typhoon quality wind >100 knots, the furthest off I've been is 43nm with the tests I've made using SH4.

This is navigation as I know it to really be. (less foul wx, of course)

You can always press CNTL Left mouse button to see where you really are if you're truely lost.

Let me add a VERY important point.

Just prior to going to Python to enter your data, you must do a SAVE. This save is what tells Python where your boat is last located for real.

So, every celestial sight you make you must also do a save-game and you must keep the name exactly the same each time. this writes-over preexisting saves as you know, but also eliminates some forms of cheating or do-overs, if you will.

Hope this helped.