Telling Heading From Hydrophone Bearing

[Rykaird]

So I'm off the lovely Spanish coast in an absolute frog-drowning storm. Can't see a thing - near zero visibility. I'm submerged to conserve fuel, running due north, and I get a merchant contact, bearing 064, constant distance.

I get repeated contacts, and each bearing gets greater, as in increasing towards 90. Given I don't know his range - other than the rather non-helpful "long" - is there a way to even get an estimate so I can lay an intercept? In this weather I'm going to have to get right on top of him to ever see him.

Anyway, if there is a way, or I'm barking up the wrong sausage, let me know. Thanks!

[High Voltage]

I've read that some people make their marks on the contact line that extends from their sub at the point at which the line starts fading away. Inexact but it's a start.

I use a slightly different method:

Assuming the ship is reported as being at a "constant distance", I pick an arbitrary measurement with the ruler, say 6km for one that's reported long distance. I will make a couple of markings along the contact line at "6" from my sub, and at different intervals which will give me either the contact's course, or one that is parallel to it. By then using the nomograph on my map (download the mod) I have the distance travelled by the ship between two markings, as well as the time it has taken it to travel this distance, I therefore get a very rough estimate of the ship's speed.

Having his speed and rough course, i can plot a course that will give me a general intercept course.

Frequent hydrophone readings when i reach that spot will allow me to fine-tune my position.


Does any of what I've written make sense?

[Mush Martin]

Somewhere here there is a manual sonar tutorial.

it may even take the shape of an academy session
inl game.

I cant recall but check the list of
tools and tips in the stickies

MM

[ReallyDedPoet]

Originally Posted by Mush Martin

Somewhere here there is a manual sonar tutorial.

try here
http://www.subsim.com/radioroom/show...phone+tutorial

edit: Sorry dude, just noticed you were all over that thread.

[xlbob]

Originally Posted by High Voltage

I've read that some people make their marks on the contact line that extends from their sub at the point at which the line starts fading away. Inexact but it's a start. (snip)

That's how I did it. I play at 61% realism. Sailing to my assigned patrol area or when patroling the asigned grid, every now and then I will go to periscope depth every now and then (every two or three hours), keep the speed ahead full, and tell SO to do normal sweeping.

When I get contatc report, I got the map and zoom in to the max magnification. Once I get max zoom, I mark the end of the contatc line. I stay submerge and keep the speed and mark the contact line again, when the contact line moves., which indicate the ship is moving, I mark the end of the contact line again. After several marks, I usually end up with at least 5 marks, I draw a line connecting those marks. That line is the ship's path. To figure which direction it goes, I simply extended the line and determine where i plan to intercept it.

This method works every time for a single ship and convoys. If a convoy, simply make more marks on several contact lines. You'll be able to tell if the convoy consist of two columns or three columns, then you can position your boat inside the convoy.

When I say "every time" I mean every single time in my last 2 careers, with the last one lasted up to 6th mission

I also find out on several occasions, that when the map is zoomed in to the max magnification, the difference between the ship's position as indicated by the marking on contact line and the actual position of the ship seen through the periscope is about 100 m. The contact line shows the ship(s) to be 100 m farther then its actual position.

Bob

[Corsair]

Originally Posted by xlbob

That's how I did it. I play at 61% realism. Sailing to my assigned patrol area or when patroling the asigned grid, every now and then I will go to periscope depth every now and then (every two or three hours), keep the speed ahead full, and tell SO to do normal sweeping.

You will hear a lot more things with engines slow or full stop...

[xlbob]

Originally Posted by Corsair

You will hear a lot more things with engines slow or full stop...

Thanks Corsair, I'll keep that in mind when I start a new career tonight

Funny thing is, this may sound stupid, I often feel that I have to be at my assigned grid as soon as possible, finish my patrol and get the hell back home as quickly as I can ... don't want to spend more time than necessary at sea, it's not really safe out there

Bob

[Corsair]

Most of the time it's not in the assigned grid that you find targets...

[Rykaird]

Originally Posted by xlbob

That's how I did it. I play at 61% realism. Sailing to my assigned patrol area or when patroling the asigned grid, every now and then I will go to periscope depth every now and then (every two or three hours), keep the speed ahead full, and tell SO to do normal sweeping.

When I get contatc report, I got the map and zoom in to the max magnification. Once I get max zoom, I mark the end of the contatc line. I stay submerge and keep the speed and mark the contact line again, when the contact line moves., which indicate the ship is moving, I mark the end of the contact line again. After several marks, I usually end up with at least 5 marks, I draw a line connecting those marks. That line is the ship's path. To figure which direction it goes, I simply extended the line and determine where i plan to intercept it.

This method works every time for a single ship and convoys. If a convoy, simply make more marks on several contact lines. You'll be able to tell if the convoy consist of two columns or three columns, then you can position your boat inside the convoy.

When I say "every time" I mean every single time in my last 2 careers, with the last one lasted up to 6th mission

I also find out on several occasions, that when the map is zoomed in to the max magnification, the difference between the ship's position as indicated by the marking on contact line and the actual position of the ship seen through the periscope is about 100 m. The contact line shows the ship(s) to be 100 m farther then its actual position.

Bob

Awesome. And here I was trying to use trig, the stopwatch, and a bunch of other stuff to solve it.

I thought the hydrophone information was bearing only - I didn't know that it provided a reasonably accurate estimate of distance as well. Going to max zoom is a great tip, and using this data to map convoy columns is also very useful.

Gentlemen, thanks very much to all of you for your assistance with this problem. I've learned an awful lot on this thread, and a tremendous amount of faulty guesswork on my part has just been eliminated from my patrols.

[Corsair]

Originally Posted by Rykaird

So I'm off the lovely Spanish coast in an absolute frog-drowning storm. Can't see a thing - near zero visibility. I'm submerged to conserve fuel, running due north, and I get a merchant contact, bearing 064, constant distance.

I get repeated contacts, and each bearing gets greater, as in increasing towards 90. Given I don't know his range - other than the rather non-helpful "long" - is there a way to even get an estimate so I can lay an intercept? In this weather I'm going to have to get right on top of him to ever see him.

Anyway, if there is a way, or I'm barking up the wrong sausage, let me know. Thanks!

Doesn't look good... As you travel slow, if it is a medium speed, you can forget it. Long range is anything above 3 Kms but could be a lot more. If you put your ears behind the hydrophone, you should get an idea from the sound if it's really far. Since you're travelling north and the contact is constant distance moving from 64 towards 90, it's probably heading something near south, which is your opposite direction.
As anyway you won't be able to make a proper attack in these visibility conditions, I wouldn't even bother trying to catch him.

[BigZed]

When your sonarman finds a contact hit "H" to go to the sonar and search within the bearing range that he called out. When you find the proper bearing of the ship click the "hydrophone" station button then click "sonar" then click "find range to target" or "range to target". As long as you keep the needle on the target bearing (in the top right corner it should say "merchant" or "warship" or "unknown") then after a few seconds you will get a reading of how far the ship is. Once you get that hit the checkmark in the pad at the upper right corner and that will send the info to your attack periscope.

Right now ive just started to learn how to manual target ships and fire torps manually so my "realism" settings are about 81% or 85% something like that. That is how i find my range to targets when submerged and dont have enough time to open the recognition manual.

[GreyBeard]

Originally Posted by BigZed

When your sonarman finds a contact hit "H" to go to the sonar and search within the bearing range that he called out. When you find the proper bearing of the ship click the "hydrophone" station button then click "sonar" then click "find range to target" or "range to target". As long as you keep the needle on the target bearing (in the top right corner it should say "merchant" or "warship" or "unknown") then after a few seconds you will get a reading of how far the ship is. Once you get that hit the checkmark in the pad at the upper right corner and that will send the info to your attack periscope.

Right now ive just started to learn how to manual target ships and fire torps manually so my "realism" settings are about 81% or 85% something like that. That is how i find my range to targets when submerged and dont have enough time to open the recognition manual.

I must be missing something here. What does opening the recognition manual have to do with the range to a particular target?

[immortal44]

I assume when he's surfaced he finds the range using notepad, which requires you to identify the ship in order to find the range.

[Rykaird]

I read the manual for the hydrophone tutorial, but it seemed to address only determining speed of the target, not the bearing.

I think there must be a way to determine heading from repeated bearing measurements using:

1) the time gaps between the bearing changes (hypothetical example - to move from a bearing of 60 to 65 degrees took 2 minutes, but from 65 to 70 degrees took 1 minute - this would imply he's closing).

and

2) a rough estimate of his speed (e.g., slow = 5 knots, medium = 9 knots).

I'll noodle on it some more. It seems like a series of triangles. And as we know, the triangle is all powerful.

[greyrider]

i'm pretty sure your target is at a 90 degree right angle to you already, as long as it keeps saying constant distance