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Mav87th 07-29-2007 07:03 AM

[REL] SH4 v1.3 Real Navigation Mod
With permision from Kaleun Freddie and Vanjast i have compiled a mod for Real Navigation for SH4.

It is similar to the mod for SH3, but with differencies.
The differencies being that its based on my Menuxxxxxxx.ini file and that i have modded the camera- and scenefiles to be as close to real as possible.

First the visibility has been increased to about 20km with a Horizon setting of 2300 upped from the default 1000 that gives 8km. This first of all enables you to track ships over the horizon from the masts and funnels, but allso puts the horizon at the correct "level" for SR and SS measurements.

Secondly the periscope, binocular and TBT angular angles has been fixed to you can measure correct altitudes of fx. landmass with the scope. I dont know how accurate the landmass altitudes are, but IF its somewhat precise you can plot from land sightings now non the less.

Thired I have deminished the sunsize to the real live angular size of 0,5 - so it will be a lot smaller then your used to. Same value goes for the moon as it shares angular size with the sun.

Fourth I have allso made a new sextant image that pops up with the stopwatch, and is draggable with it. To me this works just fine as im used to use the stopwatch anyway when taking sun rises/sets.

I have included all the documentation that has helped me to figure out how to do this incredebly complicated way of navigating - im sure glad i live in the age of GPS... :arrgh!:

Best Regards
Martin "Mav" Vinther

It can be downloaded here:

ps. I can not respond to questions the next week or so due to vacation, so please be patient.

sqk7744 07-29-2007 12:28 PM

Mav87th Very Cool!

downloading now :up:

CaptainCox 07-29-2007 12:58 PM

YEY! Way cool. you actually see the smoke stacks????
Could you post the tweaks, cause I need to do this manually. Please!

Mav87th 07-29-2007 04:21 PM

CaptainCox i guess you meen the fixes to the scene.dat file only right?

If so you need to alter the tweek file by appending the green lines shown here:




END of the scene.dat tweekfile

Then you open Scene.dat via the Tweeker tool and make the setting for the Horizon to be 2500 - voila 20km visibility.

Mind i said i could see the stacks - not the smoke it self.....

CaptainCox 07-29-2007 10:15 PM

Cheers man. Will have a look when i wake up properly here (DARN CATS!, hungry and its only 5 AM, back to bed):dead:

Uber Gruber 07-30-2007 06:03 AM

Brilliant Mav...and about time too, what took you ? :arrgh!:


ICApproval 09-19-2007 06:08 PM

Plot Course question

When I load this mod I can no longer plot a course. Am I doing something wrong? I must be!


leovampire 09-20-2007 02:42 PM

this is about manual navagation if you read the read me's for the mod you will see information about what it changes in your game for you to use this properly. Very complicated yes but if you want real life navigation for the 40's before GPS this is the way to go.

Just another way to add more realism to the game for the people who want it.

It teaches you in the read me's how to plot corses and know where you are by using the sexton and maping out everything in the sky to figure out possition and course.

Good luck!! I tryed to do it just couldn't get the hang of it. Good for people who have tryed and was able to sail this way in real life.

ICApproval 09-20-2007 05:37 PM

Thanks so much for this clarification - makes sense now.

I do love the revised periscope features for view and magnification. Any way to make just these changes?

leovampire 09-20-2007 06:37 PM

I will go back over the data in a while and see what can be done and get back to you on it just have to check some stuff for our mod release so give me some time then I will get info to you unless someone wants to help you before then.

WernerSobe 09-20-2007 10:57 PM

i wonder when a manual cooking and manual cleaning up the toilet mod is going to be released. Seriously, what is the navigator good for? A captain is not supposed to track the location of the sub.

I appretiate your work but i have no desire for manual navigation, since im playing captains role and have to concentrate on captains tasks not on the crews. I try to do that in every aspect. I never fire the deckgun on my own and only use sonar and radar stations when it is realy unavoidable due to missing tasks of AI crew.

Now about navigation. I remember another game called "B17 the mighty eight". It was pretty much the same as silent hunter but in a B17 bomber. You ware managing the crew, meeting decisions and if you wanted you could switch to any crew members seat and drop the bombs, shoot at bandits or - navigate...

So why did i mentioned that? The navigation in that game was incredibaly cool. There was a map view simmilar to the one in silent hunter. But it wasnt a godeye. Everything on the map was put in there by the crew and the crew wasnt perfect. The navigator was trying to couple the position of yourself and everything around by looking outside at cities, coasts, roads etc. When there was nothing to see he tried to couple using speed, heading and known wind. But after a while he was totaly lost and your plane was not necessery where it was shown on the map. But the navigator was telling you when he was not sure about present position or when he was totaly lost. In that case you could go to the nav map and drag your plane on it to where you think you should be, or you could look outside yourself and try to find a reference point. That is how real visual navigation work and it was very good in that game. You could never be sure if your position on the map was where you realy were, and you often came out of a cloud cover and found yourself somewhere else and could even here the navigator cursing :-)

Of course there are no referation points that can be used in a sub. Seamen use the sun, stars and the clock. But the same idea would realy improve the game. Making the navigation vulnurable to errors. So the navigator would update the location every few hours and when the visibility condition didnt let him, your position would be flawed or postponed until he can see the sun or the stars again.

That would kickass but you know it is not possible because it goes to deep into game mechanics. Anyway, so far ill stick with GPS mode.

have a nice day.

don1reed 09-21-2007 07:18 AM

Good post, Werner.

I'm one of those old guys that still enjoys celestial navigation. It's something I still love to do in real life. Why? Well, it's become a lost art from the Naval Academys point of view anyway, as most have relagated their sextants to the museums and archives...eBay...(heck of a way to treat a scientific instrument)...and opted for new, modern, GPS systems. There's nothing wrong with that concept amoung peaceful nations.

...but, in the event...(may the maker prevent)... some future nuclear mishap causing a major elelctro-magnetic interruption, the human race may need a "fall-back" line of defense, such as typewriters, sliderules, sextants, and radios with tubes instead of transistors and ICs..and where will the souls be, the next generation, who'll know how to use them ?

I like the option of being able to choose this RealNav mod just to keep alive the knowledge of the past, the skills needed to get from point A to point B...although, I will admit...the rendition of the sextant in the mod is no where near as accurate as what a real sextant would be able to provide.

The USNaval Academy's standard of accuracy, when cel nav was still being taught there, was 0.5 moa or (1/2 nautical mile) (1000 yards).

Hopefully, a new generation of players will see this mod and it will peak their curiosity to do further research into the whole realm of navigation, mathematics, and science in general.

As passengers on space-ship earth, we don't have much say

Uber Gruber 09-21-2007 08:43 AM

I'm one of those players who was/is attracted to the whole idea of manual navigation and watched the accompanying threads with great interest. Even bought a book or two on Astronomy and another on the history of Longditude (exciting book) but sadly I still can't get my head around what I have to do in the game.

I think its because I lack some basic understanding of celestial navigation. I'm quite good at maths so i think its a conceptual thing. I read all the read mes with the mod but still just can't get the hang of it :-( I found they assumed us beginners had a certain level of knowledge which I unfortunately dont have :doh:

Can anyone reccomend a resource for the absolute beginner to start with ?


don1reed 09-21-2007 12:24 PM

Hi UG.

I think what a lot of folks don't see from the git-go, is that one cel nav observation only provides us a Line Of Position (LOP). After we take several cel nav sights spaced apart by several hours during daylight (sun), then we can advance our first LOP to our most recent sun sight based on the distance we travelled since taking the first sight, (called a running-fix), and usually (if we did everything right), the two LOPs intersect. Its at the point of intersection where we then construct (pencil & straightedge & protractor) our true heading and position on the chart.

Usually, sailors do this in the morning, noon, & evening.

At night, they use stars, planets, moon. Whats different at night (evening/morning twilight accually) of course is that its possible to get three or more heavenly bodies during one sighting. (spaced about 120 apart) This provides a FIX. No need to do a running-fix as with the sun alone.

Sometimes during daylight its possible to observe sun and moon fix, this also eliminates having to do a running-fix.

...and thats the short 'n long of it. more thing...just like shooting torps at a target...the closer that two LOPs are to 90 intersection, the more accurate the fix.

JimRat 09-21-2007 01:41 PM

Celestial navigation 101
Basically when you are taking sights of Celestial objects with a Sextant you are measuring the "height" of the object above the horizon, measured in degrees. The distance for the base of the Trigonometric Formula is assumed to be the Observer's horizon, (based on their height of eye above the surface of the Earth / Sea, i.e. Sea Level). When you apply this measurement to a world chart, (not that you need to, but for illustrative purposes), you would get a circle plot that would show everywhere on the globe that the observed object would be at that height. Now if you were to observe several objects at roughtly the same time then you would end up with several global circles plotted, however there would be only one place on the globe where all the circles would intersect. That is really what is going on when you use Celestial Objects for Navigation. There are several factors that can upset the accuracy of your observations; indistinct horizon (i.e. Haze), inaccurate time measurements, (this is why Celestial Navigation at sea was not very accurate until the late 18th Century), and misidentification of the Celestial body observed, (there are roughly 52 stars used for navigation plus the Sun, Moon, and 5 inner planets, of course not all 52 stars and/or 5 planets are available at any one time).

In the morning and evening normally 7 stars and/or planets would be observed, cloud cover permitting. This would be done during the time known as Nautical Twilight, (roughly 30 minutes before Sunrise and 30 minutes after Sunset). When observing morning and evening stars as it is called, you must advance or retard the resulting LOPs to a common time, (as you can observe only one object at a time). The usual method is determining a mean time between the first observation and the last and applying the ship's coure and speed to each observation for neccesary amounts of time to reach the "mean time" of observation. This should result in a fairly tight intersection of the LOPs generated. Also if you observe the Sun as it is rising or setting the resulting LOP, (Line Of Postion), would be a Longitude line. While if you observe the Sun at LAN, (Local Apparent Noon), then the LOP is a Latitude line.

As don1reed stated during the daylight hours the moorning Sun Line would be advanced to the Noon Sun Line based upon the vessel's course and speed during the intervening hours, and then again both lines could be advanced to the afternoon sight. The inaccuracies can creep in based upon multiple course and/or speed changes and bad record keeping of the same. The biggest factor that can mess up your sights though is a bad Time Reference, this is why most vessels used to keep at least two Chronometers onboard to compare against each other to track GMT, (or Zulu time in the military). These would be compared against a time signal received by the vessel via radio each morning and a log kept on each Chronometer as to how far ahead or behind it is of GMT and whether it is gaining or losing time.

Another thing, (at least in the Northern Hemishpere), at night one can take a sight of Polaris, (North Star), anytime the view of the horizon permits, to obtain a Latitude LOP. This however is not possible in the Southern Hemisphere as there is no "South Star" available for such a sight.

Now the resulting Arithematic to reduce the observations to LOPs is very complicated if one were to do them by hand, however the formulas have been greatly reduced, (i.e. simplified to basic math), by using Sight Reduction Tables that I assume are published by many governments around the world, and here in the USA by the US Naval Observatory, coupled with the use of the Nautical Almanac published by several sources, (USNO, UKRNO, etc.).

I hope this has been helpful to those of you new to the idea of Celestial Navigation, however please remember that accuracy in this area of Navigation usually takes many Years of practice, (which is why competant Ship's Navigators used to be so prized in the Merchant Marine and in the Naval Services around the world).

JimRat, (former Quartermaster Second Class USNR):up:

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