Estimating convoy's range and course at long range with hydrophone only

Wolfcat · 03-15-19, 02:53 PM

For a single ship, I can use Kuikueg's method to deduce course and range using bearing info from hydrophone only. But I am having issues with a convoy. There are many ships in a convoy. It is hard to pinpoint the exact bearing for a single ship. So is there a better way to get a pretty accurate course and range info on a convoy at long range? My usual method is to get course and range info at very long range then sprint ahead along the course to lie in wait.

bstanko6 · 03-15-19, 03:32 PM

I always guesstimate. As long as I know if the convoy is getting closer or going away, I can guesstimate everything else.

Here is my method, less accurate but easier.

Deepseadiver · 03-16-19, 07:53 AM

More good info cheers.

Quick question for you.

I have located a convoy which is about 10km away heading NNW.

i'm way behind it at SSE how do i get into a position to attack it?

Its night time also.

03-16-19, 08:35 AM

Quote:

Originally Posted by bstanko6

Here is my method, less accurate but easier.

Hey Bstanko6, I watched your video and have few questions:
About the detection ranges of player itself as well as sonar man, is the ranges you point out default in SH3? Does the (in)experience of the sonar man or equipment type change these values?
Are they modified in common mods (e.g. megamods)? Do you know do they apply to SH5?

bstanko6 · 03-16-19, 12:49 PM

@Mussalo...
If I remember correctly, yes the default distance for hydrophone operator is 20km. As he is promoted he has less errors. I can't remember which mods change values but he is 20km.

As far as SH5 goes, I do know these values. I continue to use the SH3 values, and it works just fine for me.

The only drawback is TWoS removed the merchant tags, and some of the triggers.

My purpose in hydrophone hunting...
Not for accuracy, but for general direction! My plotting underwater mat not yield perfect results, because I do not want to spend most of the time just sitting there plotting while the target slowly moves away. I want to get my boat into visual range as soon as possible, and from there make better attack course calculations.

Pisces · 03-16-19, 05:28 PM

There is no way to get a narrow bearing to a specific ship in the convoy. By listening yourself, from the sound guy calling out bearings, or drawing sound on the map. You never know which ship the sonar guy locks on to. And if you listen yourself you lack knowledge of the layout of the convoy. The sound of a specific ship spans about 10 degrees either side. So guesstimating the middle is not very accurate.

[EDIT] On second thought, the crew should always lock on the nearest unit. So, it's roughly closest to the midpoint. But you can't tell which that is until it becomes visual.

But with convoys you don't really need to. They are so wide that you'll likely run into one of it's members eventually. Just aim for the middle of the sound of merchants. (ignore the sound of leading or trailing escorts as you try to find the middle) I personally initially just move along the bearing to get close. After a certain time I dive again to get a second bearing. If it is different than the first one then I steer a couple of 10s of degrees left or right accordingly to get a lead pursuit on it's course. After subsequent bearing checks I steer more stronger. When you make contact you can do a proper end around on the edge of visibility.

Or you can make a guesstimated intercept drawing.
1: Determine your intercept speed. Make sure you are faster than the convoy.
Draw a circle anywhere on the map, with the size of the circle (radius length) representative to your speed. The center will be the point of origin for this drawing. The arrow direction is arbitrary but preferably away from target course to not make it cluttered. (Black in the drawing)
2: You make an assumption on his maximum speed, unless it is known from a map marker. (Consider the worst case that is reasonable: 9 knots for slow convoy, 13 knots for medium speed convoy, 20 knots for taskforce)
3: Make an assumption on his course. Or if you really do not know, choose a direction 90 degrees to the sound true bearing line, as it has drifted over time.
Draw a circle concentric to the previous one. (centers on top of each other) Have the circle radius of this one point in the direction of the target course. And make it's length to scale to the target speed. Use the same scale for your speed and his speed. (Red in the drawing; you may need to use a line tool instead to get the direction aimed correctly)

4: From the tip of the (red) target speed radius draw a line in the direction of the target true bearing. Make it extend to outside of the black circle. (Blue line)

5.: Make note of where the blue line and the black circle cross. From the center of the circles to that point is the direction of your intercept course. You can measure that with most line tools. (Green line)

As you get more concrete data on the target, or find your actual average speed of intercept, you can easily refine the drawing without making a complete new one. You just re-position the (target) arrow and adjust the lines to the intersections. You can even use this drawing in a slightly different way once contact is made to avoid getting closer yet direct your excess speed to circle around/get ahead. (Bonus tip: use a protractor for that instead of the target true bearing line)

p.s. I use this mod-let I made to more easily point the map-drawing tools in specific directions.

bstanko6 · 03-16-19, 07:06 PM

@deepseadiver...
You need to start overhauling! Surface, flank, dive, reaquire, alter course, surface, flank. Easy!

Deepseadiver · 03-16-19, 08:22 PM

Quote:

Originally Posted by bstanko6

@deepseadiver...
You need to start overhauling! Surface, flank, dive, reaquire, alter course, surface, flank. Easy!

ok here goes

bstanko6 · 03-16-19, 08:36 PM

If it’s night time you have less worry of being spotted, but if it’s daytime you’re gonna have to keep those masts of the ship at a distance and keep diving when you lose sight of them just to make sure that you’re with in the area of the convoy and just keep doing that procedure until your far beam to make your attack course.

Wolfcat · 03-18-19, 08:33 AM

@bstanko, I have watched your tutorial and tried it in WAC. I don't think it works. I think some mods alter the reporting ranges.

Deepseadiver · 03-18-19, 09:35 AM

Quote:

Originally Posted by bstanko6

If it’s night time you have less worry of being spotted, but if it’s daytime you’re gonna have to keep those masts of the ship at a distance and keep diving when you lose sight of them just to make sure that you’re with in the area of the convoy and just keep doing that procedure until your far beam to make your attack course.

thanks worked a treat.

bstanko6 · 03-18-19, 03:55 PM

@wolfcat...

You are right. Nygm uses a sensor mod that changes those values. You have to find your values in your mod programs.

bstanko6 · 03-18-19, 04:20 PM

@wolfcat...

Just to be clear, you do not need exact sensor ranges for hydrophone hunting. It’s not supposed to be exact. The objective is to get an idea of where the contact is, and a general direction. And then make visual contact with that target. Good luck!

Wolfcat · 03-19-19, 01:40 PM

Understood. I just use the bearing info from AI and do the math myself. I use Kuikeuge's method to get a pretty good range and course estimates. For convoy, I usually do a very long range surface measure on one of the ships. That works very well for me, especially at night. I surface in, launch a spread and get out quickly. But the issue is in late war, staying on surface too long=suicide. To pick out a single target using hydrophone is very difficult. So this is where I need most help on. Perhaps, use a radio intercept?

03-15-19, 02:53 PM	#1
Wolfcat Chief Join Date: Nov 2012 Posts: 325 Downloads: 27 Uploads: 0	Estimating convoy's range and course at long range with hydrophone only For a single ship, I can use Kuikueg's method to deduce course and range using bearing info from hydrophone only. But I am having issues with a convoy. There are many ships in a convoy. It is hard to pinpoint the exact bearing for a single ship. So is there a better way to get a pretty accurate course and range info on a convoy at long range? My usual method is to get course and range info at very long range then sprint ahead along the course to lie in wait.

03-16-19, 07:53 AM	#3
Deepseadiver Torpedoman Join Date: Oct 2010 Location: Kingston upon Hull Posts: 116 Downloads: 64 Uploads: 0	More good info cheers. Quick question for you. I have located a convoy which is about 10km away heading NNW. i'm way behind it at SSE how do i get into a position to attack it? Its night time also. Last edited by Deepseadiver; 03-16-19 at 09:09 AM.

03-16-19, 05:28 PM	#6
Pisces Silent Hunter Join Date: Dec 2004 Location: AN9771 Posts: 4,892 Downloads: 300 Uploads: 0	There is no way to get a narrow bearing to a specific ship in the convoy. By listening yourself, from the sound guy calling out bearings, or drawing sound on the map. You never know which ship the sonar guy locks on to. And if you listen yourself you lack knowledge of the layout of the convoy. The sound of a specific ship spans about 10 degrees either side. So guesstimating the middle is not very accurate. [EDIT] On second thought, the crew should always lock on the nearest unit. So, it's roughly closest to the midpoint. But you can't tell which that is until it becomes visual. But with convoys you don't really need to. They are so wide that you'll likely run into one of it's members eventually. Just aim for the middle of the sound of merchants. (ignore the sound of leading or trailing escorts as you try to find the middle) I personally initially just move along the bearing to get close. After a certain time I dive again to get a second bearing. If it is different than the first one then I steer a couple of 10s of degrees left or right accordingly to get a lead pursuit on it's course. After subsequent bearing checks I steer more stronger. When you make contact you can do a proper end around on the edge of visibility. Or you can make a guesstimated intercept drawing. 1: Determine your intercept speed. Make sure you are faster than the convoy. Draw a circle anywhere on the map, with the size of the circle (radius length) representative to your speed. The center will be the point of origin for this drawing. The arrow direction is arbitrary but preferably away from target course to not make it cluttered. (Black in the drawing) 2: You make an assumption on his maximum speed, unless it is known from a map marker. (Consider the worst case that is reasonable: 9 knots for slow convoy, 13 knots for medium speed convoy, 20 knots for taskforce) 3: Make an assumption on his course. Or if you really do not know, choose a direction 90 degrees to the sound true bearing line, as it has drifted over time. Draw a circle concentric to the previous one. (centers on top of each other) Have the circle radius of this one point in the direction of the target course. And make it's length to scale to the target speed. Use the same scale for your speed and his speed. (Red in the drawing; you may need to use a line tool instead to get the direction aimed correctly) 4: From the tip of the (red) target speed radius draw a line in the direction of the target true bearing. Make it extend to outside of the black circle. (Blue line) 5.: Make note of where the blue line and the black circle cross. From the center of the circles to that point is the direction of your intercept course. You can measure that with most line tools. (Green line) As you get more concrete data on the target, or find your actual average speed of intercept, you can easily refine the drawing without making a complete new one. You just re-position the (target) arrow and adjust the lines to the intersections. You can even use this drawing in a slightly different way once contact is made to avoid getting closer yet direct your excess speed to circle around/get ahead. (Bonus tip: use a protractor for that instead of the target true bearing line) p.s. I use this mod-let I made to more easily point the map-drawing tools in specific directions. Last edited by Pisces; 03-16-19 at 07:21 PM.

03-15-19, 03:32 PM	#2
bstanko6 Admiral Join Date: Feb 2015 Location: Murwik Naval Academy Posts: 2,122 Downloads: 390 Uploads: 13	I always guesstimate. As long as I know if the convoy is getting closer or going away, I can guesstimate everything else. Here is my method, less accurate but easier.

03-16-19, 12:49 PM	#5
bstanko6 Admiral Join Date: Feb 2015 Location: Murwik Naval Academy Posts: 2,122 Downloads: 390 Uploads: 13	@Mussalo... If I remember correctly, yes the default distance for hydrophone operator is 20km. As he is promoted he has less errors. I can't remember which mods change values but he is 20km. As far as SH5 goes, I do know these values. I continue to use the SH3 values, and it works just fine for me. The only drawback is TWoS removed the merchant tags, and some of the triggers. My purpose in hydrophone hunting... Not for accuracy, but for general direction! My plotting underwater mat not yield perfect results, because I do not want to spend most of the time just sitting there plotting while the target slowly moves away. I want to get my boat into visual range as soon as possible, and from there make better attack course calculations.

03-16-19, 07:06 PM	#7
bstanko6 Admiral Join Date: Feb 2015 Location: Murwik Naval Academy Posts: 2,122 Downloads: 390 Uploads: 13	@deepseadiver... You need to start overhauling! Surface, flank, dive, reaquire, alter course, surface, flank. Easy!

03-16-19, 08:36 PM	#9
bstanko6 Admiral Join Date: Feb 2015 Location: Murwik Naval Academy Posts: 2,122 Downloads: 390 Uploads: 13	If it’s night time you have less worry of being spotted, but if it’s daytime you’re gonna have to keep those masts of the ship at a distance and keep diving when you lose sight of them just to make sure that you’re with in the area of the convoy and just keep doing that procedure until your far beam to make your attack course.

03-18-19, 08:33 AM	#10
Wolfcat Chief Join Date: Nov 2012 Posts: 325 Downloads: 27 Uploads: 0	@bstanko, I have watched your tutorial and tried it in WAC. I don't think it works. I think some mods alter the reporting ranges.

03-18-19, 03:55 PM	#12
bstanko6 Admiral Join Date: Feb 2015 Location: Murwik Naval Academy Posts: 2,122 Downloads: 390 Uploads: 13	@wolfcat... You are right. Nygm uses a sensor mod that changes those values. You have to find your values in your mod programs.

03-18-19, 04:20 PM	#13
bstanko6 Admiral Join Date: Feb 2015 Location: Murwik Naval Academy Posts: 2,122 Downloads: 390 Uploads: 13	@wolfcat... Just to be clear, you do not need exact sensor ranges for hydrophone hunting. It’s not supposed to be exact. The objective is to get an idea of where the contact is, and a general direction. And then make visual contact with that target. Good luck!

03-19-19, 01:40 PM	#14
Wolfcat Chief Join Date: Nov 2012 Posts: 325 Downloads: 27 Uploads: 0	Understood. I just use the bearing info from AI and do the math myself. I use Kuikeuge's method to get a pretty good range and course estimates. For convoy, I usually do a very long range surface measure on one of the ships. That works very well for me, especially at night. I surface in, launch a spread and get out quickly. But the issue is in late war, staying on surface too long=suicide. To pick out a single target using hydrophone is very difficult. So this is where I need most help on. Perhaps, use a radio intercept?