Hiding the UBoat on the Chart...

[don1reed]

@Mod afficiaonados.

Question: Is there a way to hide the Uboat on the F5 screen?

Reason: If I wanted to simulate celestial navigation, I could press an icon of a SEXTANT at the Navigators station on day/night with clear sky and it would then show my position, briefly, on the F5 screen. If its overcast, that option could not be used.

coviat: I have absolutely no idea if its possible to do in SH3, but I ask the question--Is it possible? and Can it be done?

Tnx,

[Sailor Steve]

Interesting idea. I tried not using the chart at all, but at high time compression I'm worried about running aground, as the lookouts don't call out land.

Currently I roll a die from time to time, and use the results to move my waypoints. Sometimes I end up well outside my patrol grid, or way off course while travelling. This way I end up not where I wanted, but I can still see on the chart if I get close to land.

[gouldjg]

I think it is possible

Data/menu somewhere in that folder are most of the icons needed for f5 map.

Get infranview or gimp2 via google. They are free downloads.

I cannot rememebr the whole process so trial and error on your part will be needed.

Maybe someone else will tell you the icons to look at.

[U-Bones]

data/menu/... contains icon material for other ships and platforms

For "self" representation on the map if driving a IXC for example,
data/submarine/nss_uboat9c/nss_uboat9c.tga

This file is typically used as a bearing tool overlay, but could also be null or transparent I imagine. I do not see how this could be toggled while in game. (perhaps with zoom level tweaking?)

hmm, the zoom level thought reminds me that the circle with tail representaion used while zoomed out probably IS in the data/menu area.... apologies.

[don1reed]

Tnx, gentlemen.

Toggling: I'm thinking like how the sea state toggles the use of deckguns--only CLEAR/OVERCAST skies would be the toggle for determining whether player is allowed to view his position on the chart.

Presently, as part of my seafaring prep, I use the "ruler tool" to draw a course rather than the waypoint tool. I then pull down the protractor and get azimuth courses and convert kilometers into nautical miles. I jot them down in a note book then I erase all data from the chart. I then zoom into chart where the scale is 25km long (13.5 nm) about the most one could hope to see from the bridge of a Typ 7C. I then begin patrol, making course changes based on time and speed of my notes. If the weather permits, I get a position fix, if not, I stay zoomed in.

Once every noon, called an "ETMAL", if weather allows, I place an "X" at my position...and so forth throughout the patrol. In this way I know how many nm I've made good from Etmal to Etmal.

I use SH3 Commander to knock down the TC to x128 when near land so I don't accidently run aground. When you're in Kiel and have to use the Kiel Canal to get to the North Sea, the game default is x4 TC...way too slow...anyway, tnx for the tips.

rgds,

[Myxale]

This would be a great mod Don. I really would like to see such thing in my game! But not everyone is a Obersteuerman like you! ;)
This is really gettin' interesing! I wonder how much of this is actually possible!

Your ideas are sound, and sparked my imagination when it comes to KTB. But this one would rule more!

[don1reed]

Why tnx Myxale.

Yeah, optional for sure.

Being retired, I have time on my hands, and so...I'm not under the gun to get thru a patrol as fast as possible. To me, it adds a bit more of a challenge, particularly when returning to port at night.:o Some times I exhale an audible sigh of relief (waking the Mrs) when landfall is made by sighting the Helgoland light...(at least I think it's the Helgoland light lol)

Cheers,

[Dantenoc]

I have figured out that modifying the UnitSub file in the data\menu\gui\units folder is the way to erase the circle (or dot depending on your mod) that represents your ship when not soomed in too much, but I can't get rid of the tail (defeating the whole pourpose of it all) :damn:

I'm currently using Grey Wolves, and now I could switch back to other previous mods that do away with the tails, but I don't want to change whole mods just to nick a freakin tail, anybody know what file you need to tweak?

[Dantenoc]

Forget about the method I just mentioned, this appears to be better (although I haven't played it that much yet)

Open the program files\silenthunteriii\data\menu\cfg directory and edit the maps.cfg file. Change the settings on the navigation map to:

[Map0]
MapID=Navigation_map
Position=0,0
Resolution=1024,656
MajorSqrs=4,2.4
MinorSqrs=5,5
PixPerUnit=50
ZoomLevels=1,2,5,10,20,50,100,200,500,1000,2000,40 00,7000,10000,20000,40000; meters per pixel
InitialZoom=20000;originalmente 500
SymbolZoom=20000;units are drawn as symbols from this zoom up originalmente 10
GroupsZoom=40000;units are drawn in groups from this zoom up originalmente 100
CityZoom=10000;city names are displayed from this zoom down
KriegZoom=2000;krieg labels are separated displayed from this zoom up
HarborZoom=50;harbors will be displayed from this zoom up

Having done so, open the program files\ubisoft\silenthunteriii\data\submarine folder, then choose the folder of your favorite sub, and edit the NSS_UboatXX_shp.TGA file, making it into something invisible (that's to say, just make the whole picture a transparent blank).

There you go, the only way to see your sub is to zoom way way out, wich won't help you much for the finer details of navigation, forcing you to rely on alternate methods.

Now, about faking the sextant, any time you deem that a decent navigator could calculate your exact position, press and hold the ctrl button while clicking with the mouse on a certain point on the nav-map, you'll notice that the nav-map will shift... your boat (even though you can't see it) is right there, under your mouse cursor, so mark that spot for later reference! :yep:

As I said before, I need to play with this for a while to see what type of unfortunate side effects this has... I'll report any findings later.

[Venatore]

mate this is an aswome idea.:hmm:

[don1reed]

Great find, Dan...

...if weather permits, to simulate a good sextant fix, placing the cursor in center of map and simul-pressing cntl/left mouse gives you your position, right? If so...neat. :up: (have not tried it yet...about to.)

[kylania]

Or never press F5 :)

[Notewire]

Wow, talk about challenging, I am totally adding this to my self imposed realism rules. Awesome.

Maybe someone on GW could add a "Real Life Navigation" mod option, that would be perfect.

Highest Regards,
Yarre

[panthercules]

Now, about faking the sextant, any time you deem that a decent navigator could calculate your exact position, press and hold the ctrl button while clicking with the mouse on a certain point on the nav-map, you'll notice that the nav-map will shift... your boat (even though you can't see it) is right there, under your mouse cursor, so mark that spot for later reference!

This really sounds cool - I'm looking forward to trying this out. Only two minor problems:

1. I never have really gotten the hang of doing transparent things - it took me the longest time to get my personal sub emblem to work right. So, any chance someone can mke a transparent sub file available for download to use with this idea?

2. This points out yet another time where it would be practically essential to be able to make some notes on the nav map (so you could note when you were at the position you're marking on the map when you take your "sextant" reading) - I guess you'll just have to keep track of it on a separate scratch pad, but it sure would be nice to be able to note it right on the map - anybody succeed in modding this capability into the game yet?

[Dantenoc]

Or never press F5 :)

wouldn't that be a kick in the head:rotfl:
Hardcore :rock: hahaha

No... that realy isn't feasible... better people have tried, and they have found that the SHIII world and celestial dome are way to flawed to be actualy used for real navigation methods. Besides, we don't want to kill the navigator, we just want to limit his incredible God-like precision :up:

[Myxale]

Lo fellow Kaleuns!

Dan, i tried this approach, and i feel naked without it! But it so rules! And makes things extremly difficult!:rock:

Can you tell mewhere to look for the sunken ships icons! I wanna try something!


Anything new there?!

[don1reed]

Wish to report, Dantenoc, that it works. My findings are that the faintest trace of "compass with concentric range rings", aka spider-web, can only be seen when zoomed-in to the max...which I never use at any rate.

I use, Sale U-999's, mods for large slideout dials and TDC and so I have a good mental picture of the azimuth of my boat in relation to the target(s) relative position and/or to true north. Admittedly, it was becoming a crutch when one could actually see his boat's position on the F5 screen. It serves the notion of realism in that ships' positions do not move on real charts. Using this method, the player gets an almost blank chart accept for the "spawning" of radio contacts (depending on percentage of realism chosen at beginning of play.)

http://img233.imageshack.us/img233/1355/constantbr1ey.th.jpg (http://img233.imageshack.us/my.php?image=constantbr1ey.jpg)http://img160.imageshack.us/img160/1061/salestdcqq7.th.jpg (http://img160.imageshack.us/my.php?image=salestdcqq7.jpg)

It's still possible to employ your brilliant method of target interception, although with a little more room for error, which is fitting and proper and definitely more challenging.

Well done, everyone.

[Jager]

Wow, talk about challenging, I am totally adding this to my self imposed realism rules. Awesome.

Maybe someone on GW could add a "Real Life Navigation" mod option, that would be perfect.

Highest Regards,
Yarre

Not to forget a tutorial or something to show us how to do it. What would also be cool is if we had the grid squares broken down even more (for example, AM52-69 instead of simply (AM52). Still, a real life navigation mod will do just nicely :yep:

[Dantenoc]

Can you tell mewhere to look for the sunken ships icons! I wanna try something!


It's the TGA file named:
"ShipDestroyed"
located in folder:
"C:\Program files\Ubisoft\SilentHunterIII\data\Menu\Gui\Units"

[antidotos]

Interesting discussion,
Just a question about navigation during WW2, I have read that at least some US subs had some early inertial navigation systems. Anything similar in any German sub ?

[don1reed]

both had very accurate gyrocompasses.

see: http://en.wikipedia.org/wiki/Gyrocompass

[panthercules]

Can you tell mewhere to look for the sunken ships icons! I wanna try something!


It's the TGA file named:
"ShipDestroyed"
located in folder:
"C:\Program files\Ubisoft\SilentHunterIII\data\Menu\Gui\Units"

Hmmm - when I went to look at this file, all I saw was a blank white square (checked both my current GW install and my spare clean stock game install) - what's up with that? (Using PaintShop Pro 7). I've been thinking about mapping out all my sinkings for a while and the post above reminded me about it, so I was hoping to find a suitable sunken ship graphic. Is there some reason it's invisible?

[Dantenoc]

Yes, it's invisible... I saw it with a program called Gimp2.2, which you can download from the internet for free, which has this very annoying, but useful, checkerboard background when you open up a file, which permited me to see the WHITE icon. Something to do with the fact that white a color over a white background isn't the same as something completely transparent, which has absolutely no color at all.

[panthercules]

Weird - I wonder how it shows up in the game when it's invisible in the file?

At any rate, I got tired of trying to figure out how to see the game's ship marker so I just went into Paintshop Pro and mocked up my own sunken ship map icon, and I now have a very cool map of all my current Kaleun's sinkings. To avoid hi-jacking this thread any further, I started another thread about it, so you can see it here if you want:

http://www.subsim.com/radioroom/showthread.php?p=313868#post313868

Now, if I can just figure out this transparent thing (or someone could post the file to make your sub disappear on your nav map as discussed in one of the previous posts in this thread), I'm definitely going to give this navigation technique a try - it sounds very cool.

[Myxale]

Can you tell mewhere to look for the sunken ships icons! I wanna try something!

It's the TGA file named:
"ShipDestroyed"
located in folder:
"C:\Program files\Ubisoft\SilentHunterIII\data\Menu\Gui\Units"

Ta mate! Will tinker with that one!:hmm:

[antidotos]

Thanks for the link Don1.

[JohnnyBlaze]

Jumping out of my pants :rock:

This is gonna rock my boat! I have tweaked the files and I'm going to test em right away.

Thanks Don for the wonderful idea and thanks Dantenoc for letting us know how to do it

I'm like a kid in the candy shop :rotfl:

[panthercules]

Well, yet another failure - I just don't seem to be able to get the hang of making things transparent with Paintshop Pro. I've tried a couple of times to replace my sub's marker with just a transparent square, but it keeps coming out as a black square in the game's Nav Map (even though it shows up as white in Paintshop Pro).

Can anybody put me out of my misery here and make a transparent sub marker file that works with this approach available for download somewhere? Sure would appreciate it.

[panthercules]

LOL - there's more than one way to skin a cat, as they say - I just reduced the size of my replacement .tga file to 1 pixel by 1 pixel, and voila! - effectively invisible.

I discovered of course that you can't use the "plot course" tool/option with this approach, as it reveals your boat's location, something I should have realized from reading the earlier posts but hadn't "connected the dots" until I saw it in action.

I'm really going to miss the bearing tool and the ability to plot sightings for speed calculations and intercepts - this is definitely going to be a challenge :yep:

[Sailor Steve]

"connected the dots"
:rotfl: That's great, given the subject.


Is it possible to erase the boat's location on the Nav Map, but still have it on the attack (TDC) map? That would solve the problem of plotting speed, range, AOB etc.

[panthercules]

OK - anybody got a solution for this little problem? I've got my boat hidden on the nav map, and I'm trying to set my course and figure out where I'll probably be at dawn when I have to submerge. However, I'm still charging batteries, so when I use my engine telegraphs to set my speed, I'm of course going a few knots slower than usual at any given speed setting, and will be for a while till my batteries charge, then my speed will increase. This is going to complicate my navigational computations, as compared to being able to travel the entire time at a constant speed.

Therefore, I thought I would be able to get around this little problem by setting my speed to a specific number of knots on the alternate speed indicator. However, even when I try to order (say) 10 knots on that alternate indicator, I still only get about 8 knots while I'm charging batteries. You would think that when I order a specific speed, my engine room would give it to me whether I was charging batteries or not (assuming I wasn't trying to set it faster than my boat could go while charging batteries, which I wasn't), and would know to keep it at that speed once the batteries are full.

Is there any way to make the game give you a constant speed when you order it regardless of battery status?

[edit] Not a huge problem, I guess - my estimated position was only about 12.5 km off from my actual position after 8 hours' cruising. This is going to be very interesting :)

[Notewire]

Ok, back on course with this thread, so to speak (I am terribly clever you see)

I have everything in order, but still at many of the closer zoom levels I see my boats little "circle" of radians given to me by my ubermods, anybody know how to erase these angles, as they give away the position of my boat!!

Thanks in advance,
Yarre.

[bigboywooly]

OK - anybody got a solution for this little problem? I've got my boat hidden on the nav map, and I'm trying to set my course and figure out where I'll probably be at dawn when I have to submerge. However, I'm still charging batteries, so when I use my engine telegraphs to set my speed, I'm of course going a few knots slower than usual at any given speed setting, and will be for a while till my batteries charge, then my speed will increase. This is going to complicate my navigational computations, as compared to being able to travel the entire time at a constant speed.

Therefore, I thought I would be able to get around this little problem by setting my speed to a specific number of knots on the alternate speed indicator. However, even when I try to order (say) 10 knots on that alternate indicator, I still only get about 8 knots while I'm charging batteries. You would think that when I order a specific speed, my engine room would give it to me whether I was charging batteries or not (assuming I wasn't trying to set it faster than my boat could go while charging batteries, which I wasn't), and would know to keep it at that speed once the batteries are full.

Is there any way to make the game give you a constant speed when you order it regardless of battery status?

[edit] Not a huge problem, I guess - my estimated position was only about 12.5 km off from my actual position after 8 hours' cruising. This is going to be very interesting :)

Well if you know your going to get 8 kts when you order 10kts when charging you can work out your course using 8kts as speed
Recompute when charging over

[panthercules]

Well if you know your going to get 8 kts when you order 10kts when charging you can work out your course using 8kts as speed
Recompute when charging over

Well, yeah it just makes the computation more complicated - no biggie but it would be nice not to have to do that.

[Dantenoc]

OK guys, this is the file that I use for my "invisible" sub:
http://files.filefront.com/NSS_Uboat9b_shptga/;5538755;;/fileinfo.html

Feel free to use it if it will help you. My method for hiding my sub in the navmap is replacing the "zoomed-in" version of the sub with this blank transparent file, and then change the settings on the nav-map configuration file so that it will show the "zoomed-in" icons in all but the farthest of zooms.

And yes, using waypoints does give away your position, so refrain from using them unless you are very close to land (in which case it doesn't matter if your position is given away, your navigation officer should be able to fix your position on the map very easily if within sight of land)

[panthercules]

There you go, the only way to see your sub is to zoom way way out, wich won't help you much for the finer details of navigation, forcing you to rely on alternate methods.

Hmm - maybe it's just me, but after playing around with this for just a bit I'm beginning to think there's something a little backwards about the logical/theoretical basis for this approach. I like the concept a lot, but it feels like it's been implemented backwards. Consider this...

The "navigational uncertainty" that it appeared we were trying to simulate with this seems to me to be essentially that we shouldn't know exactly where we are in relation to the "world", i.e., the things we see on the map at the lowest zoom levels (zoomed furthest out from our sub), yet the way this is implemented we lose sight/track of our sub at the highest zoom levels (zoomed furthest in on our sub).

This has the effect of making it virtually impossible to plot and track contacts during the approach/attack phase (when zoomed in pretty close to our sub), when in reality regardless of how far off we may be from our expected position in the "world", we actually should have a really good idea of exactly where we are in relation to the enemy ships that are within detection range of our sub. If I spot an enemy ship bearing (say) 60 degrees at a range of 7,500m, then I know exactly (within reasonable spotting error ranges) where my sub is in relation to that ship (and vice versa), and I should be able to easily plot both of those positions on my nav map. Yet, with this mod/approach, I can't see my sub when zoomed in to these levels, and I've lost the bearing circle, so drawing a line from my sub out 60 degrees to the target becomes practically impossible.

It seems to me that if this could be flipped around so that you could see your sub on your map when zoomed in close but you could not see where your sub is on the map when you are zoomed fairly far out (at the levels where you would be plotting your major course settings and intercept plots for targets/convoys reported many km away, where the uncertainty as to where you are in the "world" would be most relevant), this would be a much more useful/realistic addition to game play.

Could this be flipped around like that, or will it only work the way it does now?

[Dantenoc]

It can be very easily flipped around, then what you would need to do is get rid of the tail and sub circle icon, and change the nav-maps config file so that it goes into icon mode for every zoom but the highest zoom-in levels... It would work perfectly, except for two unimportant side effects: a) you would probably have to eliminate the tail from ALL the contacts. b) other sub contacts would also be invisible.

I would advise against it though... I think it's OK if you can look at your boat when zoomed realy realy far away. In my game I have it so that the sub appears on the map only when the zoom is so far out that the map is almost worldwide... I think this is good, because even the most incompetent of navigators can give you a rough guess of where you are (i.e.: "somewhere north of spain"). Even if you mark your position on the map when in such a large scale, when you zoom back in you'll find that your mark has a margin of error that can easily be a couple hundred kilometers... which is exactly the effect were looking for.

On the other hand, when you zoom in on the map, that's when the scale becomes more precise and meaningfull, and seing your sub at such scales would allow you to get a fix on your sub without any meaningfull margin of error (hence we make it invisible).

As to not seeing your boat in relation to the enemy boats when zoomed in... What enemy boats? The God's eye view should be turned off when you play hardcore :rock: !!!

It's not such a big deal... you don't realy have to know where in the map your boat is, because the enemy's position is never given in relation to the map, but rather, it is always given to you in values relative to your subs position... It's vector mathematics: translations and rotations of your axis of reference have no impact on the firing solution. If your sub is stationary, just pick any random point in the map and mark it as your sub's position and the plot the enemy's position relative to that. If your sub is mobile... well, it get's a bit tricky, but you still don't need to know your exact position to figure out a firing solution.

If I have the time I'll post more about this later.

[don1reed]

These unique nav problems were not unknown to any navigator operating before the advent of GPS. Wx permitting, three celestial sightings were taken per day, dawn twilght, noon, and evening twilight...giving them a "RUNNING FIX". http://www.dtic.mil/doctrine/jel/doddict/natoterm/r/00949.html The "circle of doubt" aka assumed position aka estimated position, was always there--and still are today if you don't use GPS.

...also, to note--ships would make a degaussing run (demagnetize) when leaving the harbor and also run a known nautical mile--in this way, with stopwatch, they would time their track over the known course at a certain speed to determine their true speed and how much drag the undergrowth caused.

As was suggested earlier, wx permitting, do a noon sight (cntl/mouse click), place an "X" at the cursor...do a noon sight the following day aka ETMAL, place an "X". Now, measure the distance between "X's"...giving you your distance made good and course made good and S=D/T aka SOG (speed over ground).

Observing that when running free-lance (without using the waypoint tool) Wx, set, and drift will come into play causing you to drift off course and increase and/or decrease speed due to wind and current...welcome to a little piece of reality :)

edit: remember in the movie, "DAS BOOT", where the Navigator tosses his pencil at the chart in disgust when the Kapitän asks for a position? During that storm sequence, they were without a celestial sighting for over a week...that "circle of doubt" was growing larger by the day.

[panthercules]

As to not seeing your boat in relation to the enemy boats when zoomed in... What enemy boats? The God's eye view should be turned off when you play hardcore :rock: !!!

What enemy boats? The enemy boats that I have detected. I play with GW's normal settings (as far as I remember) so the enemy boats are not shown on the map (except I do still get some contact reports for convoys reported at some distance, but they don't move/update on the map) - but I do make marks on the map myself when I spot the enemy ships (visually or by hydrophones, although the latter are obviously just my best guess at distance based on my assessment of the strength of the screw noises so they have a large margin of error), and I like to be able to plot out the distances and such between my boat and the enemy ships I've spotted and am tracking through observations.

I realize that I can just pick any random spot on the map, pretend (for plotting purposes) that my boat is heading due north, and use the bearing circle pull down tool that always points "0" to the north to plot some relative bearings and distances (actually, it's the first time I've found a use for that bearing pull-down, which is kinda cool). In fact, I tried that last night when I stumbled onto a task force with an escort carrier (my first carrier sighting since day 1). I think it worked pretty well too, better than I expected, but I didn't get a chance to put it to a real test as I got detected by one of the destroyers and chased under before I could get into a good firing position (I went ahead and tried a long shot with a couple of T3s but to no apparent avail).

I think this is a pretty cool way of turning SH3 into a "navigator simulator" and not just a "captain simulator", and I think that's a pretty cool addition to the game play. I liked playing around as navigator during my course setting phases, having to make a decision about whether to risk surfacing for a position check at noon and risk being spotted by aircraft (which raised a question - could they do a position check through the periscope or did they have to surface?), and seeing how far off course I was from my estimated position when it came time to surface after dark to charge batteries, etc. And I found myself actually looking forward to a run of several days in a row of stormy weather to see what that would do to my course/position plotting. And I think it would be a good challenge to see if I could intercept a convoy spotted in a certain position on the map a grid or two away when I wasn't really sure where my own boat was.

I'm just not sure if I'm up for trying to be the navigator during the last phase of the attack approach when I need to focus most of my attention on being the captain, so I was thinking I might like it better if this could be flipped so that the navigator could take over and keep track of where we were at those high-zoom levels (simulated by my sub appearing on the map at those close-in levels) while masking my sub's appearance in the further-put zoom levels where I would be plotting intercept course on distant contact reports or setting course to my patrol zones, etc. If I have enough self-discipline to keep from using ctrl+click to locate my boat when I'm not "supposed to" using this method (and I do), I think I'd have enough self-discipline to avoid using my boat's appearance on the zoomed-in map levels to defeat the purpose of it not being visible on the zoomed-out levels.

I may give a try to flipping this around and see if I can make it work - thanks for the info and the inspiration - this is a really neat concept - it amazes me that folks are still coming up with such cool new stuff so long after the game's debut. Keep up the good work :up:

[don1reed]

Forgive my "novice-graphics" but here is a rendering of nav/target problem:

http://img74.imageshack.us/img74/9048/aats2.th.jpg (http://img74.imageshack.us/my.php?image=aats2.jpg)

Own course: 050T
Own speed: 13kn.

draw circle with compass with arrow pointing to 050T with length @ 13 to represent speed. (Use moveable protractor to locate course.)

Lookout spots target BR 315 (BR = bearing relative) range 9.1km, 315 + 050 = 005T. Use moveable protractor and ruler tool, mark with "X".

3:15 min later...

targert BR 295 range 7.4km, 295 + 050 = 345T, measure and mark with "X".

Use compass tool to layoff target's RELATIVE heading and RELATIVE distance travelled in 3:15. (distance between "X's".)

Pull the center of the small circle to the tip of own course arrow. (see drawing above)

Use ruler tool to measure from own location to tip of target's arrow. This is his TRUE course and speed, i.e., 060T 10.9kn.

This method is using the chart as a Maneuvering Board.

[Dantenoc]

Excellent work guys :up:

I hesitate to report that I have found a potentialy big bug with our developing method... I discovered, while traveling through a somewhat strong storm, that the helmsmen don't do squat to maintain course heading. After you order something like "new course 45 degrees" the virtual sailors in your sub just make sure that your sub initialy points in that direction and then they let it go for itself without any course corrections at all (unless you set waypoints, but that would defeat the whole purpouse as already mentioned previously in this thread).

I was perfectly willing to accept problems with drift (that was part of the challenge we were looking for), but not problems with the boat being deflected off it's bearing by strong seas and not have the helmsman compensate by turning the boat back towards the intended heading... The stupid sailors behave as if they didn't have a compass on board :nope: . Under rough seas, in relatively short periods of time (about 4hours game time) I've had my boat change it's heading by about 15 degrees :huh:. So that means that you have to keep a very close eye on your compass heading because your crew sure won't :down:

[don1reed]

No, Leeway, is not a bug, Dantenoc. It's a known variable-constant(wx, tides, current) confronting navigators daily, the reality I spoke of earlier. This, in effect, means that the waypoint tool as far as this game is concerned--training wheels.

[panthercules]

No, Leeway, is not a bug, Dantenoc. It's a known variable-constant(wx, tides, current) confronting navigators daily, the reality I spoke of earlier. This, in effect, means that the waypoint tool as far as this game is concerned--training wheels.

I'm not sure I'm reading Dantenoc's post correctly, but it sounds like the actual compass heading is changing, and not just that the boat is winding up off course. To me, it would be one thing if the compass stayed set to 45 degrees but the boat wound up 15 degrees off course (that would be "drift" in my view), but it would be something entirely different if the compass heading actually changes from 45 to 60 degrees (which is what it sounds like Dantenoc is saying is happening) - that would sound like "crew incompetence" to me.

I had one stretch the other night where I wound up several degrees off course, further off than I expected to be or had been previously, but I didn't notice anything about the compass setting - I'll have to pay more attention next time and see if anything is going on with the compass heading.

[don1reed]

:) I've been over this ground many times.

The sim compass always shows where your boat is heading. The simple test while in free-lance is to up the tc to x1024 and while on a particular course during foul wx...watch the compass drift right/left--this is indicating leeway--whatever the cause. As mentioned earlier, navigators relied on the ETMAL (noon to noon) position to determine COG, SOG, & CMG, SMG.
course over ground
speed over ground
course made good
speed made good

When landfall is made, one can fully realize and appreciate the joy and celebration due to the sailor, home from the sea.

There is nothing precise with real navigation due to all the variables involved, until the navigator can apply with mathematical certainty the discipline of celestial navigation to fix his position on the planet.

Leeway is omnipresent in both ocean and air. Nothing that flies or floats can avoid it. All we can ever hope to do is compensate for it. Many have experienced the phenomenon while crossing a bridge over a windy pass on a motorcycle, or hiking upon a windy trail. Navigating at sea or in the air presents unusual problems as there are no trees or hills to duck behind.

The navigator can plan a course from A to B, using D=SxT, but after leeway (wx, current, tides) take hold, he won't know how much drift or set have taken place until the time has passed, whereupon, he can compute the amount using vectors or maneuvoring board. Course A to B is always subject to change, the navigator can only guess his destination and put his ESTIMATED position on the chart...until it is confirmed or rejected via celestial fix.

Example of compensation:

own course 300T
we've determined 10° east drift
compensate course to 290T

Confirmation: Time runs out...was landfall made?

Gentlemen who navigate for a living indicate a course A to B in short segments, each segment was from noon to noon. They would draw a COG from one noon to the next noon, but it was only an estimate. Through celestial they would then fix their location and they could easily see the drift or set between the estimate and true fix. They would then draw their next COG segment from the fix toward their destination...this process is repeated day after day after day until port was reached.

Here's a typical nav worksheet mid-ocean showing courses adjusted by fixes:

http://img102.imageshack.us/img102/7494/afixgn5.th.jpg (http://img102.imageshack.us/my.php?image=afixgn5.jpg)

[panthercules]

I understand all the navigational theory, though I appreciate your explanation which is very clear and helpful. But I believe what Dantenoc was talking about was changes in the actual course indicated on the compass wheel. I just ran a brief test and while sailing for a couple of days at high T/C through variable winds (6 to 12 m/s) I did notice a very slight "trembling" of the compass heading indicator (which I would interpret as the boat being pushed off course occasionally and the helmsman correcting for it from time to time), but I also noticed that the compass seemed to have moved so that it was indicating a course of about 266 degrees instead of the 270 degrees I had "ordered" at the start. And, sure enough, when I plotted my position at the end of the run and compared it to my starting position, I was off by 4 degrees to the south of where 270 would have put me.

Now certainly, a variance of 4 degrees over that length of time (which amounted to about 30Km or so) seems reasonable in terms of drift/navigational error, and maybe the only way for the game to make this "error" occur is to actually change the compass indicator by the 4 degrees of the error. I guess it would just seem more realistic/normal if the compass heading would say 270 the entire time but you would still wind up being off course a few degrees like I was.

All in all, not any real problem at just a few degrees, though if I was seeing 15 degree variances it would certainly look odd to see the compass set to 255 when I had ordered 270. Also, seeing the compass deflected that way tends to telegraph the direction and extent of the navigational error, which we're trying to hide by suppressing the image of our sub on the map in the first place.

[don1reed]

Roger that, Panthercules. I apologize if I seemed condescending or over informative with my explanations; but, on a forum as this, one never knows if what one writes could perhaps become the inspiration or spark of inventiveness in the casual reader. Maybe it could spawn interest.

I've witnessed the deck watch asleep at the switch too. Usually, during foul wx when I'm trying to outflank a convoy or target...especially when seas are Beaufort 7 or 8 (15 m/ps) at higher TC. It requires constant vigilence at the helm to make rendezvous with target(s) using this method.

[panthercules]

Roger that, Panthercules. I apologize if I seemed condescending or over informative with my explanations; but, on a forum as this, one never knows if what one writes could perhaps become the inspiration or spark of inventiveness in the casual reader. Maybe it could spawn interest.

I've witnessed the deck watch asleep at the switch too. Usually, during foul wx when I'm trying to outflank a convoy or target...especially when seas are Beaufort 7 or 8 (15 m/ps) at higher TC. It requires constant vigilence at the helm to make rendezvous with target(s) using this method.

No offense taken or apology necessary - I found your explanations clear and helpful, and this whole thread has indeed inspired me to play around with some (for me) hitherto unexplored areas of gameplay, which is very cool. I was just trying to point out that this particular point about the compass heading was (at least for me, if not for Dantenoc - he'll have to speak for himself on this one) not about the navigational theory, but just the way the game's compass indicator works in these situations. I suspect it can't be changed, but people are figuring out so much already maybe they could figure out how to make the compass stay "as ordered" but let the boat drift anyway - just a thought :)

[JohnnyBlaze]

Well this thread has already cought my attention and I believe I wont be the last one.

I've been experimenting this method also for a couple of hours and I'm actually really enjoying this navigating.
Before you guys brought this up I used to plot my course by myself once ina while, but also did use the waypoint system when I the captain were too busy to plot manually.

For me this game is a simulation and I like to keep things as realistic as possible, but I do like to use my Officers every now and then to do the job for me.

Okay back to the point. I've had pretty good results with manual plotting my course and position. Usually I end up five kilometers over the point where I think I should be. :damn:
I really think that my calculations are correct, but it might be the speed changes. I patrol at 7 knots speed decks awash just west of Britain near the coast.
Also I find that compass course change a bit annoying too.


Thanks guys for showing me the path :rock:

[don1reed]

Well Done, Johnny Blaze!

You can get sweaty palms when heading back to port in fog or a storm...trying to make landfall...those harbor lighthouses are a Godsend.

[JohnnyBlaze]

Well Done, Johnny Blaze!

You can get sweaty palms when heading back to port in fog or a storm...trying to make landfall...those harbor lighthouses are a Godsend.

Thank God it's been sunny and calm for the whole patrol (7 days).
Well actually I've been waiting for the storm to come to really test my navigating skills.

[Dantenoc]

Well, it's official. If your sailing in rough seas, the waves can actualy push the nose of your sub and make turn into a different compass heading. After fooling around with the sub for a while using time compression, I have been able to observe a change in course of up to 50 degrees in about 10 hours.

Guess that means you can't trust your helmsman to maintin compass heading, so we'll have to keep a close eye on that when time compressing. :shifty:

[Dantenoc]

I realize that you can take celestial readings at almost any time with the right equipment, but what would be realistic to do? One reading at the crack of dawn and another at sunset?

[don1reed]

In real life, three times per day:
dawn
noon
evening

that is, wx and enemy activitiy permitting.

[Sailor Steve]

Well, it's official. If your sailing in rough seas, the waves can actualy push the nose of your sub and make turn into a different compass heading. After fooling around with the sub for a while using time compression, I have been able to observe a change in course of up to 50 degrees in about 10 hours.

Guess that means you can't trust your helmsman to maintin compass heading, so we'll have to keep a close eye on that when time compressing. :shifty:
The problem is that in real life the helmsman steers by the compass; that is he is constantly correcting to keep the ship on the same compass heading.

The boat will almost certainly drift from its assigned course, which is why sightings have to be taken, but it will NOT change headings. For the game to do this is very wrong.

[panthercules]

Well, it's official. If your sailing in rough seas, the waves can actualy push the nose of your sub and make turn into a different compass heading. After fooling around with the sub for a while using time compression, I have been able to observe a change in course of up to 50 degrees in about 10 hours.

Guess that means you can't trust your helmsman to maintin compass heading, so we'll have to keep a close eye on that when time compressing. :shifty:
The problem is that in real life the helmsman steers by the compass; that is he is constantly correcting to keep the ship on the same compass heading.

The boat will almost certainly drift from its assigned course, which is why sightings have to be taken, but it will NOT change headings. For the game to do this is very wrong.

Yeah - seems that way to me too - I like the fact that you actually drift off course, but I wish the compass heading indicator would stay put on the heading ordered - I'm sure that the helmsman wouldn't sit there and let the compass indicator drift very far off 270 before he corrected to get it back on 270 (and if he didn't, I could always shoot him and replace him with someone who would keep us on the ordered heading) - he certainly wouldn't let it slide 15-50 degrees off the ordered course like we seem to be seeing here.

Too bad the game didn't get that part quite right. As long as we know what's happening though, I suppose we can learn to just ignore the compass indicator setting during these stretches of our voyage (maybe click it over to the rudder indicator so we can't see the compass moving off target) and just focus on elapsed time so we won't be tipped off as to how far off course (or in which direction) we've drifted.

I'll give that a try if I ever shake these escorts and get back to the surface again :)

[Dantenoc]

Well, no... you can't ignore the helmsman's incompetence, you have to watch him very closely and not let him steer of course.

Drift is simulated independently of the direction at which your sub's nose is pointing... at least I've seen my boat travel in a side step fashion by as much as 3 or 4 degreee when I could still see the sub on the navmap on very high zoom (before making it invisible)... so always pointing in the right direction will still give us drift (which is good)

So, that now brings us to a different subject: what would be the best mod to have to allow us a BIG compass on the screen (the stock one is so small that it's hard to read).

P.S.: I noticed in Grey Wolves that the wall mounted compasses (command room and hydrophone station) don't work correctly... the outer dial showing your heading in 10's works ok, but the inner dial that shows the las digit in your degree heading seems frozen (at least in my game) to the "1" position.

[don1reed]

P.S.: I noticed in Grey Wolves that the wall mounted compasses (command room and hydrophone station) don't work correctly... the outer dial showing your heading in 10's works ok, but the inner dial that shows the las digit in your degree heading seems frozen (at least in my game) to the "1" position.

...the UNITS dial has never worked since day one. IIRC it was modded before GW or NYGM, it was made to emulate pictures of real compasses in uboats. I remember folks on the forum asking what it was for. At any rate it was part of the gyro-compass/repeater system...not the magnetic.

[Sailor Steve]

So, that now brings us to a different subject: what would be the best mod to have to allow us a BIG compass on the screen (the stock one is so small that it's hard to read).
'Six-Dials Simfeeling mod' is the best as far as I'm concerned. Nothing on the screen at all most of the time, which makes it easier to make screenshots, and everything is a slideout. It takes a little work to install it, but the results are...well, see for yourself:
http://www.subsim.com/phpBB/viewtopic.php?t=48292

[JohnnyBlaze]

Well how's the navigating going on guys?

I hope you guys havent given up allready? :hmm:

I'm still practicing for that storm to come, cuz it's been all :sunny:.

[Dantenoc]

well... it's hard to say. I've pretty much gotten used to the idea of not seeing my boat when zoomed in, and I've learned how to plot my own position as well as the enemy's position simultaniously. So that part is cool. As a matter of fact, now that I've gotten the hang of it, I think it's better and now makes the original feel kinda gamey (having a magical map that updates your position in real time with no margin of error).

Also, ploting intercept courses when the enemy's position and general heading is reported to you, but when you don't exactly where you are is kinda fun also, and realy not very dificult to do.

However, the helmsman's incompetence is quite frustrating, since you have to keep a close eye on him and continuously drop from TC in order to correct him. This problem is greatly exagerated in bad weather, and it really demands a lot of time from you if you want to play this way (you can't really TC to high or for too long) I wish there was a "repeat last order button" so that I could continously yell at him "Keep course 218!!! Keep course 218!!! Keep course 218!!!" without having to constatly drop from TC in order to adjust the boat's heading.

[panthercules]

Wow - finally escaped the task force that had me pinned down, and had my first chance to stalk a single merchant with this new method - it really did add a whole new dimension not being able to just plot the course with the waypoint tool with pinpoint precision, and instead having to rely more on visual sightings and hydrophone readings, and having to compute the timing of various course and speed changes to get into position.

Very gratifying indeed to find myself still able to get into perfect firing position and send another British C2 to the bottom with a pair of well-aimed magnetic shots below her keel that broke her apart and sent her down in a blaze of fire and explosions and probably the best smoke plumes I've seen in three careers (my first chance to observe the cool new smoke mod from Sober - very awesome indeed :up: )

Hats off and a hearty Well Done! to you hard core navigators who figured this out :rock:

[Immacolata]

Wish to report, Dantenoc, that it works. My findings are that the faintest trace of "compass with concentric range rings", aka spider-web, can only be seen when zoomed-in to the max...which I never use at any rate.

I use, Sale U-999's, mods for large slideout dials and TDC and so I have a good mental picture of the azimuth of my boat in relation to the target(s) relative position and/or to true north. Admittedly, it was becoming a crutch when one could actually see his boat's position on the F5 screen. It serves the notion of realism in that ships' positions do not move on real charts. Using this method, the player gets an almost blank chart accept for the "spawning" of radio contacts (depending on percentage of realism chosen at beginning of play.)

http://img233.imageshack.us/img233/1355/constantbr1ey.th.jpg (http://img233.imageshack.us/my.php?image=constantbr1ey.jpg)http://img160.imageshack.us/img160/1061/salestdcqq7.th.jpg (http://img160.imageshack.us/my.php?image=salestdcqq7.jpg)

It's still possible to employ your brilliant method of target interception, although with a little more room for error, which is fitting and proper and definitely more challenging.

Well done, everyone.

What is that interesting compas rose thingy you have to the right? I would like that for my own game, never saw that before. And I really could use a precise compass for my scope.

Being a complete and utter landlubber by divine right (I get seasick for just about nothing to my sailing fathers great dismay) how would I get to figure out how to do manual navigation in SH3? Is there a tutorial that one can follow? I know there are various drawing tools on the nav map you can use, and I know from my math class that you can do lots of nice calculation with a pencil, a protractor and a ruler :)

[don1reed]

Go here, http://www.subsim.com/radioroom/search.php?searchid=47533 (http://www.subsim.com/radioroom/search.php?searchid=47533), to find, FLB sale U-999's mods for large slideout dials and TDC.

-...-

while in port, I use the ruler tool to draw my courses that I'll follow out to the patrol square. I jot the courses and distances down on a note pad. I then erase them from the F5 screen.

I use the D = S x T (distance = speed x time) formula to figure my times at various speeds to each waypoint...note...a waypoint is usually where I make a course change from my original drawing.

While underweigh at each noon, if the wx is good (or partly cloudy), I press CNTL left mouse button with cursor in the middle of the screen, to simulate a sextant observation and to get a noon fix of my position. I place an "X" at each fix location.

I use the ruler tool to measure the distance between each noon fix to determine my true course over ground and my true speed. Once you've done this a few times you can easily determine how much you need to adjust your heading to put you back on track to your destination.

Once you reach your patrol square and complete your mission, do a reciprical to get you back to home port.

edit: I usually begin my drawing with the ruler tool just on the outskirts of the harbor, not from the U-boot pens. While you're in the harbor, just free-lance navigate until you get to the last (simulated) sea buoy and enter the open sea.

cheers,

[Immacolata]

Eh so how do you navigate close to land? You might see a lighthouse, but you do not have sea charts do you?

Another question is how you manage solution making for torpedo shots? That sounds really tricky when you are unsure of your own position?

[don1reed]

Coastal piloting can present some very tricky situations, i.e. night, fog, hvy rain, or all three.

If you're heading into homeport--making landfall during any or all three of those conditions will cause you to sweat, particularly if it was a successful mission up to that point (pray for lighthouse) :)

However, if your style of play takes you into foreign/enemy harbors :huh: Now we're talking excitment! Again, if any or all three of those conditions present themselves--you might want to abort...depending on your manly fortitude.

It depends on the accuracy of your most recent fix. You can of course surface or use your scope to take bearing on coastal sightings, i.e.,

land sighted, bearing 315° or 45° (relative) start your stop watch...when that piece of land gets to 270° or 90° (relative) stop your stop watch and do the math to determine how far you stand off, as now you have two pieces of the D=SxT formula, your own speed and time.(45-90-45 icosoles triangle). You will also be able to draw a running-fix, where the first bearing is brought forward and crosses the second bearing.

or, lets say you stand off a small cove from the seaward side--take bearings on each side of the cove, then do a resection (reciprical azimuths) to determine where the two bearings cross--indicating your location. (Both sites must be identifiable on the chart)

Once you have a position fix you can then draw headings to take from that known position. Its wise to update as often as possible thru other sightings and/or running fixes.

[panthercules]

OK - how about some practice tips here, if anybody knows for sure.

First, as I asked at some point above, does anybody know whether it was possible to take enough readings through the periscope to do a noon sighting without having to surface? I would think maybe they would have figured out how to do this, but I'm not sure. Without confirmation though, I guess I'll assume that I'll have to surface the boat to get a sighting fix.

Second, while I've seen indications that the boats would typically take sightings at noon, dusk and dawn or some such schedule, does anybody know for sure if you have to take these readings at any limited number of specific times to get a good idea of your position, or could you take it at any time of day or night (assuming clear enough skies, of course) and then make adjustments factoring in the time of day/night to get to an acceptable position determination?

Basically, I'm looking for some realistic/practical "rules" for when it's legit for me to use "ctrl+click" to fix the location of my boat on the map.

[don1reed]

Only two things are necessary to take a celestial observation:

1) Clear view of the horizon, and; (real or artificial)
2) Clear view of the celestial object of interest.

This is why the hours between morning through evening twilight are the best.

If wx/visibility permitted, a round of stars, and/or moon, and/or planet(s) in the early twilight...3 or more objects spaced approx 120° apart would produce a great fix. This fix, later coupled with a pre-noon sun sight would produce a running-fix; this running-fix coupled with a noon sun sight produced an updated running-fix, etc., until an evening twilight round of stars and/or objects would put a finer point on it...a daily routine.

The NLSR Zeiss aka Observation scope had the range of movement to vertical view almost 90° but did not have split-image like the US Kollmorgen; however, all sextant observations were taken from the bridge while surfaced. Later in the war, when the Germans went to mainly schnorchel use to survive, they were developing a scope to use for navigation, but, alas, the war ended before it was finished.

[Dantenoc]

huh?... I don't know much about navigating, but you don't seem to mention night observations as a posibility. I understand that the sextant only works when you can distinguish the horizon, but even without the sextant, shouldn't it be easier still at night?... you have so many celestial bodies to choose from at night, that you could easily pick three and triangulate your position, no? :-? ... or where they so dependant on the sextant that they didn't bother teaching alternative methods to the sailors? :hmm:

Maybe I need to do some research about this and learn a thing or two :yep:

About the only do the Ctrl-click sextant thing while surfaced... sounds reasonable :up:

[don1reed]

Sorry, no. No sights are taken after evening twilight due to "fading" of the horizon. Without the precise measurement afforded during day/twilight, the inaccuracies could place the vessel's position 1000's nm away---even during a full moon. We've all seen moon reflections on an open body of water---yet, if you have ample optical equipment, you can sometimes see the dark horizon beyond the beginning of the reflection...giving the viewer a false horizon due to the bright moon and contrasting surrounding dark night.

Also, observations of celestial bodies viewed at low altitude are suspect due to all the altitude corrections and possible inherent math errors. Even with all the modern tables simple math errors always crop up. Even though low altitude celestial bodies are not recommended...due to wx/visibility...sometimes it's all you'll be able to view...and you gotta take what nature (sea-gods) offers you.

[JohnnyBlaze]

Okay I have finally made contact with the enemy.

I spotted a large cargo ship, but now I have a problem plotting it's course.

I use the advanced plotting mod and map updates are on.
The thing is I cant see the target any more on the map when I have visual contact with it.

How do I intercept the target when I dont know it's range (using NYGM), the speed nor the heading.

I did manage to get into a firing position by visually "quessing" the heading of the target, but it was far from the perfect 90 degree angle.

I've always wondered how you NYGM users determine a targets range? Using the mast height observation method or what?

Thanks

[panthercules]

Well, I'm still using GW 1.0 (was waiting for NYGM or GW to pop their next major version release - gonna load up NYGM 2.2 next time I get back to port, so I can try it out some before GWX gets here), so I'm not sure how NYGM folks do it these days, but I can attest that it is tougher to plot and make your intercepts with this manual nav approach. I was cruising along at night on the surface a couple of nights ago when my watch officer spotted a ship overtaking me from a bearing of about 190 degrees. I had been doing some tweaking about visibility/sighting ranges recently, so I wasn't sure how far away my crew would be spotting ships now, so I asked my watch officer for the range.

It started out at about 11,500m, but was rapidly dropping. Thinking it was probably a destroyer and might have already spotted me by radar (it's late 1943), I dived to periscope depth. I was about to head deep when I took another look through the 'scope and saw that it was too big for a destroyer (turned out to be a Fido class light cruiser). I put my boat into a high speed turn and tried to line up for what I expected to be about a 2,500m shot I'd probably miss, but I didn't want to pass up the chance to get a cruiser. But she was zig-zagging, and between her movement and my own I really wasn't able to take the kinds of timed sightings to determine her speed like I used to when I always knew just where my boat was on the map.

So, although (thanks to another last minute course change by the cruiser) I managed to end up in a beautiful position for a beam shot from only about 1,200m away, both my torps missed - apparently my guess as to her speed wasn't quite close enough. I hated missing the shots, but I really enjoyed experiencing what felt like a much more realistic degree of uncertainty during my approach than I was getting before with my boat's exact position displayed on the map so I could pinpoint the enemy's position and determine their course and speed so precisely.

One thing I realized during this encounter, however, was that it wasn't really necessary for me to have modded the game to suppress my boat's position in order to obtain these attack-plotting benefits - all you have to do is zoom in on any random empty part of the map, make a mark in any arbitrary position, call it your current position and start plotting from there. If you can't see your boat on the map, it really doesn't matter what part of the map you use for this close-range intercept plotting process (assuming that you aren't going to go very far from your current position during the attack phase, anyway).

Of course, once the intercept/attack is over, you do need to go back to the right general location on the map to start plotting your main course navigating, or you'll get really screwed up :)

[THE_MASK]

I watched a program on tv the other day where maoris (new zealanders) used the direction of the waves to navigate there traditional canoes. They would keep the canoe travelling across the wave at the same angle during the day and use the stars at night . Im talking like around 2000 mile sea voyage here .

[don1reed]

It got your "juices" flowing, eh? :up: ...soon as I complete my present patrol, I'll try to post some pics of the nav process that I use without the AI positions and waypoints.

@Sober: A great book regarding how the southsea Islanders navigated is one called, "We, the Navigators The Ancient Art of Landfinding in the Pacific" by David Lewis. The Polenesians are an amazing people. I've built a Proa using some of their designs...what a fast boat--forerunner to the catamaran. Does 20 knots just sitting still. :)

http://img307.imageshack.us/img307/16/acruxaa1.th.jpg (http://img307.imageshack.us/my.php?image=acruxaa1.jpg)

[JohnnyBlaze]

Thanks Panthercules for your couraging words :up:
Too bad you didnt get the Cruiser.

I was about to go back to the original thang where I could see my boat..

But as you said it doesnt matter where you are as long as you know where you are relative to your enemy. It took me some time to realize this :rotfl: Yes I feel a bit ashamed.

I did waste a couple of eels when trying to sunk a large cargo ship, because my range estimate was wrong. I was closing on the target too fast so my eels just went under the target as set for magnetic.

4 eels fired, 1 hit and finished her with the deck gun.

And now since I got the hang of it I'm not going to change back.
Still alot of practice ahead no doubt.

[Dantenoc]

Here's a short video about navigating the hardcore way :D. Resolution sucks, but I think you can get the idea.

http://www.youtube.com/watch?v=T3yDDIS1GBk
http://www.youtube.com/watch?v=9MH1GUq0_DA

Let the dialogue begin :yep:

[don1reed]

Excellent work, Dantenoc. Just for sake of discussion, the lines of position (LOP) not substantiated by celestial observation are known as dead reckoning positions (DR).

You have "nailed" the explanation. :up:

For those who wonder about leaving the Uboat's track to chase target(s)...your other explanations of "How to sink a ship" are just as valid, only now, a lot more challenging. Tnx.