Can't hear ship on hydrophone

[patio87]

There is a ship like .3 mile away from me, I can even hear his engines when I am inside my ship in the map section, but when I go to the hydrophone I can't hear him. Why can I hear him like he's right next to me, but not with my hydrophone pick him up.

And are there any good references on how to use it, like how can I figure out what way a ship is heading, all it does is tell me where the ship is relative to me.

The stickied videos up at the top of the forum are broken, the links just link to fileplanet games section, the downloads for those tdc videos aren't there.

Thanks.

[mcf1]

Welcome aboard Skipper.
Does a sound contact appear on your map? If not then the ship Is probably stationary
Is your sub diven or decks awash?
Is your hydrophone intact?

[patio87]

Yes I was at like 55 feet. Are you saying I should have heard him on the hydrophone?

[vickers03]

i had the same issue with some small fisherboats,
maybe they are not set up as sonar targets,
i checked their files but they seemed ok..
:ping:

[mcf1]

Yes I was at like 55 feet. Are you saying I should have heard him on the hydrophone?
Yes, unless you have a broken hydrophone or the ship is not moving

[Falkirion]

Are you using home and end to swivel the hydrophones? Most of the time when I go to the station I have to manually set the bearing the contact is on to pick it up.

[Seminole]

I posted a similar thread some time ago. Never got any satisfactory cures but did receive a couple of confirming replies.

Funny thing though...after I mentioned it..it has never recurred...go figure...:hmm:

So I wouldn't sweat it .It probably won't turn out to be a big deal for you either.

[SteamWake]

Given that you have followed the above suggestions (submerge a bit below Periscope depth, Rotate the hydrophone) and still dont hear the contact then...

Yes it is a rare but confirmed bug. Sometimes the sound stream for a 'contact' doesent get cued.

By the way with RFB install you can even hear the stationary boats. :yep:

Oh yea and welcome to Sub Sim Patio

[patio87]

Given that you have followed the above suggestions (submerge a bit below Periscope depth, Rotate the hydrophone) and still dont hear the contact then...

Yes it is a rare but confirmed bug. Sometimes the sound stream for a 'contact' doesent get cued.

By the way with RFB install you can even hear the stationary boats. :yep:

Oh yea and welcome to Sub Sim Patio
Hmm, well I figured it was a bug, thanks for the confirmation. BTW, what is the RFB install? And on the topic of hearing things, can other ships hear other things on my sub, other than the engines running? Like when I'm pinging the bottom to see the depth, or I ping a contact to see how far it is, are the ships somehow listening to those pings, and can they figure out where I am by my pings?

This game is crazy, it's so deep, I have so many questions, I'm loving it.

[SteamWake]

can other ships hear other things on my sub, other than the engines running? Like when I'm pinging the bottom to see the depth, or I ping a contact to see how far it is, are the ships somehow listening to those pings, and can they figure out where I am by my pings?.

It all depends on what kind of ship / group of ships...

If it is a convoy with escorts..of course they are listening, in fact pinging the range to a DD when he is close (3k yards more or less) is like rasing a flag saying "You hoo this way... here I am." :oops:

They can also hear and react to depth pings. Range I dont know ask someone else.

But basically keep the range to target in mind when using active devices.

[patio87]

Ok thanks, I figured as much but wasn't positive. What about the thermal layer, what is it, and can they hear me down there?

[Arclight]

Can't find a source right now so I'm going by memory;

It's a region / layer were the temperature of the water changes rapidly compared to the water above (and below?) it. Say the water from the surface to 80ft depth drops 5deg in temperature, and then it changes another 5deg in the next 10ft (80 to 90ft depth), then that 10ft of water would form a "thermal layer".

What it does is reflect or refract sound (and possibly other forms of energy?). This happens because the speed of sound traveling trough water is (among other things) dependent on the temperature. As the sound reaches the layer, it's speed changes, and as a result it's direction changes. It's a lot like light bending as it enters water; if you look at an object from above the surface, it appears to be in a different location then it actually is.

I think if the sound hits the layer at a very shallow angle, it is actually reflected. I think I read sometime that if the surface if perfectly smooth (0 wind), sound gets reflected back and forth between the surface and the layer, allowing anyone listening to pick up on a contact from very long ranges.

So, a sonarman listening for a passive contact or using active sonar for location, would place the contact in the wrong location (due to refraction) or would not be able to acquire a contact at all (due to reflection).

I doubt it is this accurately modeled in the game. Probably all it does is make you a bit harder to detect, by reducing the range you can be detected at under the current conditions.


Anyone please feel free to correct me, it's been a few years since I read about this stuff. :-?


* found something on refraction, also talks a bit on sound refraction (the acoustics bit): http://en.wikipedia.org/wiki/Refraction

[SteamWake]

Arclight pretty much covered it.

Game mechanic wise it decreases the odds of an active or passive sonar being able to locate you.

Its not a magic blanket though, if your thrashing around down there at speed and banging on stuff with hammers there still going to hear you.

[iksoks]

never had this happen (or better didnt notice) before i started running TMO...
Now i happens quite often..
Or even worse my sonar guy cant hear a DD going full steam 21 kn from ca 3 miles away.. When i got into the seat it kinda scared the shi* out of me he was so loud...

[Urge]

patio87
Yes I was at like 55 feet. Are you saying I should have heard him on the hydrophone?

Try going below 60'.

Urge

[Squid95]

Relating back to the original question; I have run into quite a few ships such as the smaller coastal merchants, and even coastal gun boats that will not be detected by the hydrophones. I even have a list compiled ( not on me at the moment ).

When I encountered a visual contact without a corresponding sound emission I wrote down the conact and went in the mission builder to recreate the situation. In most cases speed was the predominant factor. The ships were not detectable in the phones at speeds less then 6 knots or so. I even tried changing weather conditions which had little effect. I think I a had about a 6 ships listed that I had done testing on.

Even stranger was that in some cases my crew would detect the target and would track it, but when I took the phones I could hear nothing.

I have not fould one IJN combat ship with this issue.

I am running 1.5 with RFB and RSRDC.

[Orion2012]

Relating back to the original question; I have run into quite a few ships such as the smaller coastal merchants, and even coastal gun boats that will not be detected by the hydrophones. I even have a list compiled ( not on me at the moment ).

When I encountered a visual contact without a corresponding sound emission I wrote down the conact and went in the mission builder to recreate the situation. In most cases speed was the predominant factor. The ships were not detectable in the phones at speeds less then 6 knots or so. I even tried changing weather conditions which had little effect. I think I a had about a 6 ships listed that I had done testing on.

Even stranger was that in some cases my crew would detect the target and would track it, but when I took the phones I could hear nothing.

I have not fould one IJN combat ship with this issue.

I am running 1.5 with RFB and RSRDC.
Interesting, I too have had the same issue. Although I caught it by accident, as I have been using my hydrophones myself a lot, and have heard contacts, not sure of the range or the type, but sounded loud enough to be detectable to even the most untrained of sonarmen.

Will post back if I can find anymore info.

If you can post the list here it could be possible that there is no sound attached to those ships. There aren't separate entries for each ship.

Do you have any sound effects mods installed or did you stick with the default RFB sounds??

[Diopos]

...
Even stranger was that in some cases my crew would detect the target and would track it, but when I took the phones I could hear nothing.
...


Yeap. I've occasionally come across this behavior too.

[SteamWake]

RFB swaps out nearly ALL of the sound files for the hydrophones.

I personally have not had any trouble with them and often find distant, un classifiable contacts that my sonar man doesent. As I said before with RFB you can even pick up 'stationary' contacts.

All I can think of is 1.) your not deep enough and still in the surface boundry 2.) Something is wrong with your hydrophone gear or 3.) Your install of RFB is screwed up.

With RFB you cannot pick up contacts while surfaced, none, nada, nothing. Usually going to Periscope depth is enough, but just to make sure I typically go to about 80 feet.

[Squid95]

I had some time to kill today so I played around with the mission editor. I started from the bottom of the list of IJN merchants starting with the small old split freighter and worked my way up.

Here is how the scenario was set up. I place the merchant heading north toward Kiska. Speed was set at 10, then 8, then 6, 5, then 4. My sub was placed about 4000 yards off the starboard bow of the incoming merchant at PD and then various depths to test the phones.

So for the first test the merchant's speed was set to 10 knots. On the phones she came in loud and clear no matter what depth ( except surface ). Same result for speeds of 8 and 6 knots but when I dropped below 6 knots I could not detect the target even though my crew tracked the merchant just fine. Any speed below 6 knots had the same result.

I repeated this test for the first 5 merchants in the IJN list and had identical results. Once a merchant dropped below 6 knots it was not detectable on the phones even though my crew could track the target and I imagine if my realism was cranked down you could see the sonar bearing line as well.

These results were confirmed regardless of depth and speed of own ship but of course you have to be submerged and atleast PD to use phones.

I have no doubt that even if the merchant was dead in the water my crew would find her even though you would not be able to track her on the phones yourself. Sounds like I need to test that one.

I have not tested the same hull from multiple nations but I cant image they would be any different. Is this new information? Probably not but it does seem to relate to many questions above problems with the hydrophones.

I seem to vaguely remember something in the 1.4 or 1.5 patch read me files about this change but I havent gone back and read it again.

I wonder if anyone else has had similiar results?

One more note, my install is very clean and recent, but I am not ruling out that my install could be corrupted I just have no reason to suspect so.

[yoevro]

I know this is an old thread, but I too am experiencing this problem.
I'm able to replicate the 6 knot threshold as eplained above. Just wondering if anyone might have any more information on how to remedy this?

thanks!
Evro

[Moonlight]

I remember CapnScurvy mentioning this unusual phenomenon and this was his answer.
What's got me looking at RSRDC's campaign files for the merchants, is the finding that any merchant ship travelling at below half its maximum rated speed, will not allow the manual sonar "hearing" of that ship when you go to the station yourself. Lurker made ships vary their speeds between waypoints (as they would in real life) with different speed settings for each leg between waypoints (the stock game keeps the speed constant at 9 knots). The problem is, if a ship rated at 18 knots maximum speed drops below 9 knots between two particular waypoints......you won't hear the ship with manual sonar use. Many of RSRDC's merchant speeds drop to seven and eight knots....some even go lower.