Determining course of contact that is "smoke on the horizon"

pythos · 06-15-14, 04:46 PM

Finally got Steel Wolves and SH5 working on my rig. Now this mod has NO map contacts, and this is proving troublesome when it comes to contacts that are "smoke on the horizon". I try to plot the position, but of course all I have is bearing. Now, I have clicked on the WO's report, and that gives a range....this is nothing less than cheating. Also it seems the mod has made this unreliable. I had a contact go from 18KM to 7 in less than a minute (it was a boat, not a plane). When I got multiple reports and plots, the course of the contact was.....ludicrous. I searched here for good tutorials on plotting contacts with no map up dates, but could only find ones with updates, and were for older versions of Sh. Could someone help, or at least point me in the direction for a tutorial, or what have you concerning tracking distant contacts.

Jaystew · 06-15-14, 06:42 PM

Suppose you are heading due north and your heading is therefore 000. Take the contact's bearing from your ship. Suppose its at Bearing 060. If you want to make an intercept, first start with pure pursuit by changing your heading to that of the contact. Make heading 060.

There are 3 possible outcomes. The target can be heading...
Directly toward you (Unlikely)
Directly away from you (Unlikely)
On a different course than your course. (Most likely)

Once on that heading and at a steady speed. 10 kts is a good long range intercept speed. Note the time exactly. Note your position on the map exactly and note the relative bearing of your target exactly. (Be aware you do not need to know exactly where you are on the ocean only exactly where you are relative to each tracking measurement you are about to make.)

Make an X on the map noting your subs position. Draw a line of bearing out from that spot and extend it 30km.

At 2 minutes note the apparent bearing of the ship on the horizon. If the ship is to the left or right of your bow you can rule out that it is heading directly towards or away from you.

If the contact is still on bearing 000 and simply smaller or you've lost contact it was moving faster than you and opening distance. If the contact is larger but on the same bearing are your pursuit it is closing. It have may detected you and be on an intercept course. Likely a warship. The last possibility is that it is moving directly away but slower than you sub so you are gaining on it.

In the most likely situation the contact will be either right or left of the bow a few degrees. Remember you matched your heading to the bearing of the contact and are on heading 060. Suppose the contact is now at bearing 002.

The only thing you can conclude is that the target is heading somewhere between 060 and 240 and that it is moving.

So again at 2 minutes note that the contact is now at 062. Maintain your heading of 060 along the original bearing. Measure out where your sub would be from the original X and make a new X. From this new X draw a line of bearing out 30km.

Repeat the process at 4 min and again at 6 min. As you take more bearing measurements. Assuming the target maintains a straight course you will very soon determine the range within a few hundred meters. You will also be able to determine the targets course within 10 degrees.

That should set you up with where you need to go in the beginning.

Sailor Steve · 06-15-14, 08:45 PM

Brilliant explanation!

pythos · 06-15-14, 09:04 PM

Wow!!! That is the BEST explanation I have seen concerning this perplexing problem. This should be pinned. Gonna give it a whirl tonight Thank you.

Jaystew · 06-16-14, 03:16 AM

I didn't even think it was that good but I'm glad you guys like it. Here is part two.

The angles are not proper and only exaggerations but technically correct. You can infer alot from the angles without them being correct. Such as approximate distance and approximate direction based on where your best guess position is.

For example, so the mid range of where your plots are put the target at 15 km from your sub which is probably right. More right than if its in the range of 5km or 25 km logically if it is just on the horizon is must be in visual range which rules out 25km and if it is so small you cant make out what direction the bow is facing then it must be greater than 5km. So 15km it is approximately. Now every 2 min you can draw an approximate line between points about 15km from your sub along the lines of bearing from your visual observations which will be accurate. This will give you a general direction of travel. If you are very accurate with your time and speed keeping you will have a course of your target within 10-20 degrees with only 3 measurements. The more measurements the more accurate the inferred conclusions derived from the data.

Some considerations...

The target is moving so even if your measuring is accurate it will not explain why everything does not exactly line up. The target may also be zigzagging likely and this will add to variability in your best guess. The conclusions will derive from the best observations which will be the last 3 you made, but do not discount the previous observations and recording as they will serve to confirm direction of travel and/or conflict with your course plotting.

Also. The target may change course. If they have detected you or on the whim of the captain. In which case you may not longer need to make observations in the case where they are heading towards you to attack, or where you will need to continue to observe to again determine their new course. With even more observations you can determine their course sufficient to match it and then run parallel.

Once parallel you can increase or decrease speed to determine the speed of your contact. This will be in lesson 3 which I'll put together laters.

Oh yeah, use the nomograph to determine how much distance you travel at 10kts in 2 min. Knowing this will help you to know the larger triangle problem.

Here is a link to the grand tutorial...
http://imgur.com/a/EstMH#0

pythos · 06-16-14, 02:31 PM

After reading the first answer, I was thinking to myself how great it would to get a graphical explanation of the process, and lo and behold!!!
This is really something that has baffled me for a long time. This latest addition REALLY helps. Now I get it the point where the bearing lines intersect that gives the position of the contact!!!
This is gold.
Thank you for this, and this still should be pinned.

pythos · 06-19-14, 10:57 PM

I did my best getting some shots of what is happening. My original course is the outlined set course line visible in this first pic. I was alerted to smoke on the horizon. At the time of this shot I had turned the boat to head toward the smoke. My first X is drawn

The next shot is where I drew my bearing line based on the report (NOT the contact drawn on the map. I am ignoring that for this exercise)

Two minutes later I draw my next line

Then the next two minutes I do the same.

As can be seen the lines are fanning out, they are not converging. The target was not going fast. I was drawing the lines out to the edge of the bearing indicator, and the termination mark in no way represented the contact course.

I wonder what is going wrong here.

pythos · 06-19-14, 10:58 PM

For some reason Flickr is not allowing me to share pics that I have marked as public. I will figure it out later. kinda pissed at this. (the flickr thing, not the issue of this thread)

Depaor1970 · 06-21-14, 10:38 AM

It will rarely be the case that these bearings taken from your ship moving at 10 kts of another vessel moving at speed (say 5 -35 kts) will ever intersect. What jaystew is showing you is how to interpolate the direction of travel and with experience doing this how to guesstimate an initial course and approx. speed for your future target. The turn towards the bearing and speed to 10kts ( I normally go to 15) are all good initial actions and certainly within a few minutes u can determine approx. direction of travel and whether that contact is moving fast or slow. If that bearing to the target is steady and it is getting bigger in your sight picture but is travelling fast then its time to get the hell outta the way lol or at least prepare a good sternshot. In general though it will be a slowish moving merchant. Jaystews description of how he guestimates the initial range is important. This is what we in the trade would call "the seamans eye", it develops over time. In game I think it is similar that the more you practice this initial guesstimations the better u will learn to determne wheter it is an appropriate target you can intercept. Keep trying is my advice but do not look for a perfect solution, remember to use the visual clues available to u through uzo/binos. Is the smoke fainter or stronger, can I now see mastheads or silohette of a ship. From what I can see you are so close to getting to grips with this, just trust your instincts a bit more. remember this will not be the information you will fire your torps on this is just initial can I intercept, which way is it going and how fast and is it a viable target for me. Keep the faith Herr Kaleun.

pythos · 06-21-14, 11:33 AM

Oh don't worry, faith is not lost, I love this sim no matter how frustrating it is at times.
I Jaystew's description is very promising, and your statement about the "seaman's eye" helps a lot also.
I have for the longest time how the crew of any vessle was able to judge distance and course of a distant contact. What you say makes sense.

This sim makes it all the more impressive how the crews of these vessles were able to do as they did, without the marvels of GPS, and other such things. It is really incredible.

Depaor1970 · 06-21-14, 12:42 PM

When you initially get the observation and take bearing and turn on course, might be worthwhile to drop down and try to get a range approximation from the sonar guy. Problem with this is it slows your interception and u may lose the contact. The way I try is an aggressive burst towards that contact. Watch the direction his bearing is going and follow it or put ur course left or right of it, e.g his bearing has been drawing left 090, 085, 080 at each observation then I would steer maybe 060 and go to flank/full between observations. Same if bearing is drawing right e.g 090, 095, 100 then I would steer maybe 130. If after a period of time I am not any closer e.g 45 mins to 1 hour then I would probably give up as I am just wasting valuable fuel on a fast moving contact that may kill me or be able to outmanoeuvre a long range torpedo shot. I note where I came across the fast mover especially if I think its a fast moving high value target and may check this area out again in a future patrol to see if I have better luck. Happy hunting

pythos · 06-22-14, 12:57 PM

Found the method. Reading it now. Oh man has SH 5 taken on a new level. This is gonna suck at first, especially dealing with the CTDs, but this promises to become as close to real as one can get with this sim.
You all kick ass with the mods, and tutorials for this too often maligned sim.

pythos · 06-22-14, 03:10 PM

Then...I find in the tutorials menu of the main menu, a 4 bearings tutorial. Giving it a shot now.

pythos · 06-22-14, 06:30 PM

That tutorial is very good, I now have a good grasp of this method. Giving it a try in mission.

06-15-14, 04:46 PM	#1
pythos Grey Wolf Join Date: May 2005 Location: Somewhere over there Posts: 834 Downloads: 46 Uploads: 0	Determining course of contact that is "smoke on the horizon" Finally got Steel Wolves and SH5 working on my rig. Now this mod has NO map contacts, and this is proving troublesome when it comes to contacts that are "smoke on the horizon". I try to plot the position, but of course all I have is bearing. Now, I have clicked on the WO's report, and that gives a range....this is nothing less than cheating. Also it seems the mod has made this unreliable. I had a contact go from 18KM to 7 in less than a minute (it was a boat, not a plane). When I got multiple reports and plots, the course of the contact was.....ludicrous. I searched here for good tutorials on plotting contacts with no map up dates, but could only find ones with updates, and were for older versions of Sh. Could someone help, or at least point me in the direction for a tutorial, or what have you concerning tracking distant contacts.

06-15-14, 08:45 PM	#3
Sailor Steve Eternal Patrol Join Date: Nov 2002 Location: High in the mountains of Utah Posts: 50,369 Downloads: 745 Uploads: 249	Brilliant explanation! __________________ “Never do anything you can't take back.” —Rocky Russo

06-16-14, 03:16 AM	#5
Jaystew Sparky Join Date: Apr 2013 Posts: 151 Downloads: 50 Uploads: 0	I didn't even think it was that good but I'm glad you guys like it. Here is part two. The angles are not proper and only exaggerations but technically correct. You can infer alot from the angles without them being correct. Such as approximate distance and approximate direction based on where your best guess position is. For example, so the mid range of where your plots are put the target at 15 km from your sub which is probably right. More right than if its in the range of 5km or 25 km logically if it is just on the horizon is must be in visual range which rules out 25km and if it is so small you cant make out what direction the bow is facing then it must be greater than 5km. So 15km it is approximately. Now every 2 min you can draw an approximate line between points about 15km from your sub along the lines of bearing from your visual observations which will be accurate. This will give you a general direction of travel. If you are very accurate with your time and speed keeping you will have a course of your target within 10-20 degrees with only 3 measurements. The more measurements the more accurate the inferred conclusions derived from the data. Some considerations... The target is moving so even if your measuring is accurate it will not explain why everything does not exactly line up. The target may also be zigzagging likely and this will add to variability in your best guess. The conclusions will derive from the best observations which will be the last 3 you made, but do not discount the previous observations and recording as they will serve to confirm direction of travel and/or conflict with your course plotting. Also. The target may change course. If they have detected you or on the whim of the captain. In which case you may not longer need to make observations in the case where they are heading towards you to attack, or where you will need to continue to observe to again determine their new course. With even more observations you can determine their course sufficient to match it and then run parallel. Once parallel you can increase or decrease speed to determine the speed of your contact. This will be in lesson 3 which I'll put together laters. Oh yeah, use the nomograph to determine how much distance you travel at 10kts in 2 min. Knowing this will help you to know the larger triangle problem. Here is a link to the grand tutorial... http://imgur.com/a/EstMH#0 Last edited by Jaystew; 06-18-14 at 05:51 AM.

06-21-14, 10:38 AM	#9
Depaor1970 Swabbie Join Date: Sep 2012 Posts: 10 Downloads: 147 Uploads: 0	From my experience at sea It will rarely be the case that these bearings taken from your ship moving at 10 kts of another vessel moving at speed (say 5 -35 kts) will ever intersect. What jaystew is showing you is how to interpolate the direction of travel and with experience doing this how to guesstimate an initial course and approx. speed for your future target. The turn towards the bearing and speed to 10kts ( I normally go to 15) are all good initial actions and certainly within a few minutes u can determine approx. direction of travel and whether that contact is moving fast or slow. If that bearing to the target is steady and it is getting bigger in your sight picture but is travelling fast then its time to get the hell outta the way lol or at least prepare a good sternshot. In general though it will be a slowish moving merchant. Jaystews description of how he guestimates the initial range is important. This is what we in the trade would call "the seamans eye", it develops over time. In game I think it is similar that the more you practice this initial guesstimations the better u will learn to determne wheter it is an appropriate target you can intercept. Keep trying is my advice but do not look for a perfect solution, remember to use the visual clues available to u through uzo/binos. Is the smoke fainter or stronger, can I now see mastheads or silohette of a ship. From what I can see you are so close to getting to grips with this, just trust your instincts a bit more. remember this will not be the information you will fire your torps on this is just initial can I intercept, which way is it going and how fast and is it a viable target for me. Keep the faith Herr Kaleun.

06-21-14, 12:42 PM	#11
Depaor1970 Swabbie Join Date: Sep 2012 Posts: 10 Downloads: 147 Uploads: 0	One additional suggestion When you initially get the observation and take bearing and turn on course, might be worthwhile to drop down and try to get a range approximation from the sonar guy. Problem with this is it slows your interception and u may lose the contact. The way I try is an aggressive burst towards that contact. Watch the direction his bearing is going and follow it or put ur course left or right of it, e.g his bearing has been drawing left 090, 085, 080 at each observation then I would steer maybe 060 and go to flank/full between observations. Same if bearing is drawing right e.g 090, 095, 100 then I would steer maybe 130. If after a period of time I am not any closer e.g 45 mins to 1 hour then I would probably give up as I am just wasting valuable fuel on a fast moving contact that may kill me or be able to outmanoeuvre a long range torpedo shot. I note where I came across the fast mover especially if I think its a fast moving high value target and may check this area out again in a future patrol to see if I have better luck. Happy hunting

06-15-14, 06:42 PM	#2
Jaystew Sparky Join Date: Apr 2013 Posts: 151 Downloads: 50 Uploads: 0	Suppose you are heading due north and your heading is therefore 000. Take the contact's bearing from your ship. Suppose its at Bearing 060. If you want to make an intercept, first start with pure pursuit by changing your heading to that of the contact. Make heading 060. There are 3 possible outcomes. The target can be heading... Directly toward you (Unlikely) Directly away from you (Unlikely) On a different course than your course. (Most likely) Once on that heading and at a steady speed. 10 kts is a good long range intercept speed. Note the time exactly. Note your position on the map exactly and note the relative bearing of your target exactly. (Be aware you do not need to know exactly where you are on the ocean only exactly where you are relative to each tracking measurement you are about to make.) Make an X on the map noting your subs position. Draw a line of bearing out from that spot and extend it 30km. At 2 minutes note the apparent bearing of the ship on the horizon. If the ship is to the left or right of your bow you can rule out that it is heading directly towards or away from you. If the contact is still on bearing 000 and simply smaller or you've lost contact it was moving faster than you and opening distance. If the contact is larger but on the same bearing are your pursuit it is closing. It have may detected you and be on an intercept course. Likely a warship. The last possibility is that it is moving directly away but slower than you sub so you are gaining on it. In the most likely situation the contact will be either right or left of the bow a few degrees. Remember you matched your heading to the bearing of the contact and are on heading 060. Suppose the contact is now at bearing 002. The only thing you can conclude is that the target is heading somewhere between 060 and 240 and that it is moving. So again at 2 minutes note that the contact is now at 062. Maintain your heading of 060 along the original bearing. Measure out where your sub would be from the original X and make a new X. From this new X draw a line of bearing out 30km. Repeat the process at 4 min and again at 6 min. As you take more bearing measurements. Assuming the target maintains a straight course you will very soon determine the range within a few hundred meters. You will also be able to determine the targets course within 10 degrees. That should set you up with where you need to go in the beginning.

06-15-14, 09:04 PM	#4
pythos Grey Wolf Join Date: May 2005 Location: Somewhere over there Posts: 834 Downloads: 46 Uploads: 0	Wow!!! That is the BEST explanation I have seen concerning this perplexing problem. This should be pinned. Gonna give it a whirl tonight Thank you.

06-16-14, 02:31 PM	#6
pythos Grey Wolf Join Date: May 2005 Location: Somewhere over there Posts: 834 Downloads: 46 Uploads: 0	After reading the first answer, I was thinking to myself how great it would to get a graphical explanation of the process, and lo and behold!!! This is really something that has baffled me for a long time. This latest addition REALLY helps. Now I get it the point where the bearing lines intersect that gives the position of the contact!!! This is gold. Thank you for this, and this still should be pinned.

06-19-14, 10:57 PM	#7
pythos Grey Wolf Join Date: May 2005 Location: Somewhere over there Posts: 834 Downloads: 46 Uploads: 0	I did my best getting some shots of what is happening. My original course is the outlined set course line visible in this first pic. I was alerted to smoke on the horizon. At the time of this shot I had turned the boat to head toward the smoke. My first X is drawn The next shot is where I drew my bearing line based on the report (NOT the contact drawn on the map. I am ignoring that for this exercise) Two minutes later I draw my next line Then the next two minutes I do the same. As can be seen the lines are fanning out, they are not converging. The target was not going fast. I was drawing the lines out to the edge of the bearing indicator, and the termination mark in no way represented the contact course. I wonder what is going wrong here.

06-19-14, 10:58 PM	#8
pythos Grey Wolf Join Date: May 2005 Location: Somewhere over there Posts: 834 Downloads: 46 Uploads: 0	For some reason Flickr is not allowing me to share pics that I have marked as public. I will figure it out later. kinda pissed at this. (the flickr thing, not the issue of this thread)

06-21-14, 11:33 AM	#10
pythos Grey Wolf Join Date: May 2005 Location: Somewhere over there Posts: 834 Downloads: 46 Uploads: 0	Oh don't worry, faith is not lost, I love this sim no matter how frustrating it is at times. I Jaystew's description is very promising, and your statement about the "seaman's eye" helps a lot also. I have for the longest time how the crew of any vessle was able to judge distance and course of a distant contact. What you say makes sense. This sim makes it all the more impressive how the crews of these vessles were able to do as they did, without the marvels of GPS, and other such things. It is really incredible.

06-22-14, 12:57 PM	#12
pythos Grey Wolf Join Date: May 2005 Location: Somewhere over there Posts: 834 Downloads: 46 Uploads: 0	Found the method. Reading it now. Oh man has SH 5 taken on a new level. This is gonna suck at first, especially dealing with the CTDs, but this promises to become as close to real as one can get with this sim. You all kick ass with the mods, and tutorials for this too often maligned sim.

06-22-14, 03:10 PM	#13
pythos Grey Wolf Join Date: May 2005 Location: Somewhere over there Posts: 834 Downloads: 46 Uploads: 0	Then...I find in the tutorials menu of the main menu, a 4 bearings tutorial. Giving it a shot now.

06-22-14, 06:30 PM	#14
pythos Grey Wolf Join Date: May 2005 Location: Somewhere over there Posts: 834 Downloads: 46 Uploads: 0	That tutorial is very good, I now have a good grasp of this method. Giving it a try in mission.