Basics of Hydrophone Tracking?

[Alcibiades]

Can anyone please help with the basics of how to track a ship with just the hydrophone?

With full realism, I can only get bearing to the ship. How can I estimate the ships speed, range, and heading?


Example: I am heading 000 (north) at 5 knots. contact bearing 90. unknown range. 5 minutes later, contact is bearing 94. unknown range.

So how to estimate how far away the ship is, what it's speed is, and it's approximate heading?

Right now I just guess and try to plot an intercept until I get into visual range.

any help would be appreciated.

[Athlonic]

Originally Posted by Alcibiades

Right now I just guess and try to plot an intercept until I get into visual range.

Hi,

You are doing it right.
With WWII hydrophone you can just "guess" ...

Your sonarman with experience can estimate speed and range, that is represented in game by the length of the line on the map.

In modern submarine, sorting a passive solution with hydrophone is possible but it is still a nasty task.
You can give "Dangerous waters" a try, it is a mordern subsim that simulate passive solution perfectly.

[kylania]

Here's my post linking the previous tutorials for this issue.

http://www.subsim.com/radioroom/show...&postcount=248

Here's a handy tool to save you all the writing on the map:

http://www.subsim.com/radioroom/showthread.php?t=167103

[gutted]

You can do it while moving, but it takes more time and adds more complexity. Due to the short range of the U-Boat hydrophone however, you are better off staying in one location while doing the initial observations.

I made a moving (2 leg) version of the hydrophone tracker.. but it was just not practical for a 20km listening range. Maybe on a nuclear sub, but not a ww2 one.

[Alcibiades]

Originally Posted by kylania

Here's my post linking the previous tutorials for this issue.

http://www.subsim.com/radioroom/show...&postcount=248

EXCELLENT! Thanks Kylania. This is exactly what I was looking for!!!

Hah! now I can get range, speed, and heading all w/out ever even seeing them!

[Bothersome]

Originally Posted by Alcibiades

Can anyone please help with the basics of how to track a ship with just the hydrophone?

With full realism, I can only get bearing to the ship. How can I estimate the ships speed, range, and heading?


Example: I am heading 000 (north) at 5 knots. contact bearing 90. unknown range. 5 minutes later, contact is bearing 94. unknown range.

So how to estimate how far away the ship is, what it's speed is, and it's approximate heading?

Right now I just guess and try to plot an intercept until I get into visual range.

any help would be appreciated.

Ooohh me, pick me!!

I'll give a stab at answering this example...

Full realism, means no lines on the map (no map contacts).

OK we need to use the noodle here.

Being that the contact was reported at 90 degrees to us this means that the contact must be closing. Not going south or going north or else we would have hit at 89 or less or 91 or more.

Five minutes later it's bearing is at 94. Now we need to know how far our sonar picks up. Let's assume it picked up at 9000 yards when the sonar guy alerted us. 5 minutes later it's at 94 degrees but we have moved 5 knots / 60 minutes * 5 minutes = 0/417 nautical miles or 833 yards.

So if SIN in 4 degrees X 9000 yards = 628 yards would be the distance moved from us and we traveled 833 yards north, then target must be moving (given unknown figure of current range) roughly 280 degrees (mostly west) at about 10 knots or 270 at 5 knots.

Some guessing is required because of no new information on range. Best course of action is to turn due east and stop for a few minutes to take more bearings. If bearing increases (to your starboard) then target is going more south probably around 240. If bearing decreases then target is going more north like 290 or so. If bearing stays steady then you are in the sweet spot.

After about 5 minutes, you may need to turn the boat again before it gets into hearing range and get closer to the track and prepare a shot if enemy.

That's how I do it.

[Athlonic]

Oh my godness !

So you guys are telling us that we can have an accurate solution just with the hydrophone ?
In a WWII uboat ?

I suddenly feel stupid to have spent several hours learning how to use the passive sonar with the ruler in Dangerous waters...

[Alcibiades]

Originally Posted by Bothersome

Ooohh me, pick me!!

I'll give a stab at answering this example...

Full realism, means no lines on the map (no map contacts).

OK we need to use the noodle here.

Being that the contact was reported at 90 degrees to us this means that the contact must be closing. Not going south or going north or else we would have hit at 89 or less or 91 or more.

Five minutes later it's bearing is at 94. Now we need to know how far our sonar picks up. Let's assume it picked up at 9000 yards when the sonar guy alerted us. 5 minutes later it's at 94 degrees but we have moved 5 knots / 60 minutes * 5 minutes = 0/417 nautical miles or 833 yards.

So if SIN in 4 degrees X 9000 yards = 628 yards would be the distance moved from us and we traveled 833 yards north, then target must be moving (given unknown figure of current range) roughly 280 degrees (mostly west) at about 10 knots or 270 at 5 knots.

Some guessing is required because of no new information on range. Best course of action is to turn due east and stop for a few minutes to take more bearings. If bearing increases (to your starboard) then target is going more south probably around 240. If bearing decreases then target is going more north like 290 or so. If bearing stays steady then you are in the sweet spot.

After about 5 minutes, you may need to turn the boat again before it gets into hearing range and get closer to the track and prepare a shot if enemy.

That's how I do it.

yeah, full realism = no lines or anything. have to draw your own

Thanks for the reply. Yeah, that was pretty close to what I was doing... listening, estimating, moving, repeat. until I got close enough to see.

but the video (link Kylania sent) was excellent and showed how to get a good range, speed, and distance to the contact.


Basically the recommendation is to stay still and get 3 bearings to the target spread out over say 30 minutes. so you have your boat and three lines drawn out from the boat at locations where the contact was (30 min apart).

Then there is only one line (at a certain angle) that will cross all three lines such that the distance between each bearing is the same. Hence constant speed = same distance between each "bearing" that you took at 30 min apart.

that gives the heading.

then just draw a fourth bearing line where the contact "will" be in 30 min. move your sub and take a reading at the 30 min mark. where the reading (bearing) line you take crosses the 4th line is the contact's exact location.

And there you have it... contact loc. heading. speed (length of line between any two bearings / time between the two readings) without ever coming to the surface or looking in your periscope!




that's probably as clear as mud...

just look at the video (see link in previous post). He does a good job with explaining it!

[Alcibiades]

Originally Posted by Athlonic

Oh my godness !

So you guys are telling us that we can have an accurate solution just with the hydrophone ?
In a WWII uboat ?

I suddenly feel stupid to have spent several hours learning how to use the passive sonar with the ruler in Dangerous waters...

well not "accurate" I suppose the hydrophone range is not far enough to allow for enough time between readings for sufficient accuracy. Especially if the contact is moving fast... or heaven forbid, changes course!

But it looks like you should be able to get somewhat close. if you sit still for a hour or more. Just hope that by the time you get your final reading the contact isn't already 16km away and moving away!!!!

"I got it Captain!! I got it!!"

"got what you Hydrophone weenie?"

"the contacts exact location, heading and speed!!!"

"and?..."

"it's bearing 165, range 17km, speed 19 knots, heading 180 (moving away)... we can NEVER catch it!!!"

"errrr... great job.. thanks"

[kylania]

Originally Posted by Alcibiades

well not "accurate" I suppose the hydrophone range is not far enough to allow for enough time between readings for sufficient accuracy. Especially if the contact is moving fast... or heaven forbid, changes course!

But it looks like you should be able to get somewhat close. if you sit still for a hour or more.

The video is of a standard single merchant contact in open waters. Low speed (8kts or something) and a stable course. He goes from hearing the first contact to hitting with torpedoes without ever checking the scope.

[Alcibiades]

Originally Posted by kylania

The video is of a standard single merchant contact in open waters. Low speed (8kts or something) and a stable course. He goes from hearing the first contact to hitting with torpedoes without ever checking the scope.

I'll try his method tonight. It seems pretty straight forward -provided low speed, long distance with initial hydrophone contact, no course changes, and heading somewhat towards you or at least not away.

Thanks again for sending it. It is exactly what I was looking for - if a bit long (video).

[Platapus]

Having a person (the player) by themselves attempt realtime hydro tracking without some specialized plotting tools is going to be real hard.

A 10-point divider makes it a lot easier. It would be cooleo if someone could code in a 10-point divider into the game (all three games actually)

I seem to remember an old modern sub sim game that had something like a 10-point divider to help plot off of hydrophone bearings. I can't remember which one it was though.

To me, this is a perfect example of coding the crew's actions to help the player. In real life the Captain had a well trained crew to help with such calculations.

Just like in some of the sub sim games the player can send data to the TDC, why can't the player send data to the plot? The computer (simulating the crew) would faithfully plot what ever data the player sends it. The player makes an error in observation, well the plot will faithfully plot the errors.. just like in real life.

[jmr]

Originally Posted by Platapus

I seem to remember an old modern sub sim game that had something like a 10-point divider to help plot off of hydrophone bearings. I can't remember which one it was though.

I think you're referring to Fast Attack. Although not shown in those screenshots, it does have a TMA plotting board although it doesn't specifically have a 10 point divider.

Just like in some of the sub sim games the player can send data to the TDC, why can't the player send data to the plot? The computer (simulating the crew) would faithfully plot what ever data the player sends it. The player makes an error in observation, well the plot will faithfully plot the errors.. just like in real life.

Yes, I would absolutely love to have something like this, especially in SHIV as the fleet boats had tracking parties to do just what you described. Maybe we'll see it in Tony Hawk's Silent Hunter XXX

[LemonA]

Question regarding the hydrophone abilities of english destroyers:


Picture shows a situation from Sept. 18th 1939, 1:40 at night, in Scotish coastal waters, from a youtube-Let's-play-video ( at ca. 10:00min)


It shows 2 destroyers A and B with some detection ranges of ca. 3 or 4 km radius.

1) Are these the hydrophnoe ranges?
2). I would have assumed a not-moving destroyer has a hydrophone range of 10 - 19 km. Destroyer A is not moving, even though he has the same detection range as the destroyer B.
Why are the hydrophone-abilities of destroyers are that different from an u-boat ?
3.) Any links to read something about the hydrophone abilities of the Allied war ships in SH5?