can DDs...

[Sag75]

detect me by their hydrophones at surface? or at deck awash ?




thx!

[Brag]

Like real lookouts they can see you or missed seeing you on the surface. With decks awash is a little more difficult for them to see you. It is your job not to be seen.

[Sag75]

Hi, yes I know, but I mean.. can they detect me by using hydrophones even if I'm surfaced?

[Torplexed]

Originally Posted by Sag75

Hi, yes I know, but I mean.. can they detect me by using hydrophones even if I'm surfaced?

No. That's what radar is for.

[Sag75]

Thanks for answers, but my question is pretty technical, so in other words.. is there an upper water limit on which if you stay above it the DD hydrophone doesn't pick up you?

This may have important consequences, for example when you go up and down in stormy weather, a DD may detect you by its hydrophones!

According to the Uboat Commanders Handbook, YES, they can hear you.
I would, however, assume, that they'd have to be DIW (Dead In the Water).
That would be rather foolish of them.

So, I'll refine my answer to:
It is possible, but highly unlikely.

[Kaleu_Mihoo]

Originally Posted by Sag75

Thanks for answers, but my question is pretty technical, so in other words.. is there an upper water limit on which if you stay above it the DD hydrophone doesn't pick up you?

This may have important consequences, for example when you go up and down in stormy weather, a DD may detect you by its hydrophones!

Yes, there is a limit (in sensors.dat I think), min and max depth for all of the sensors separately.

[Sag75]

Thanks, probably it was unspoken, ..but I meant in SH3, not in real life!

[GoldenRivet]

i believe that there is a depth where the watch crew automatically goes below deck.

this is something like 8 meters depth.

every time you pass 8m the watch crew disappears - you will notice this in game if you have free cam enabled.

this is the point at which the game engine considers the u-boat to be "submerged"

i believe this is also the point at which DD hydrophones can begin to hear you underwater.

DD Hydrophones cannot hear you while surfaced above this 8 meter demarcation.

if memory serves me correctly, 300 meters depth is the maximum sensor range for hydrophones and it is also the maximum depth for depth charges.

theoretically, if your boat can survive at 301m depth or deeper, you can run ahead flank all day and never be detected.

[bertockamus]

I must say that I am somewhat surprised that they cannot hear you when you are on the surface. Although I do not know the location of the hydrophones on a DD, unlike your uboat, the DD's hydrophones are always underwater listening so why would then not be able to hear you?

You can hear surface traffic when you are just submerged (8m, but hydrophone shallower) and I suppose their hydrophones are about 2-3m down. The deeper you go, the better you can hear (notwithstanding the thermalcline, is that modeled in SH3?) because you can get away from the surface noise.

Of course weather, speed etc would play a part, but a stationary DD in calm seas I would think, could hear quite far away with their hydrophones and certainly pick up surface traffic.

I really don't know much about the technology at the time, this is just how I always thought of it. Am I missing something? Or am I wrong and the only way a DD can "see" you on the surface is visually or radar?

[GoldenRivet]

Originally Posted by bertockamus

I must say that I am somewhat surprised that they cannot hear you when you are on the surface. Although I do not know the location of the hydrophones on a DD, unlike your uboat, the DD's hydrophones are always underwater listening so why would then not be able to hear you?

For starters, your hydrophones are not underwater while you are surfaced.

the Hydrophones on a DD are located on the bow on the underside of the ship.

these hydrophones are specifically designed to search for submerged submarines.

also there is a fair degree of "surface clutter" (there is probably another name for it) but at the surface, especially in rough weather, acoustic quality is destorted to such a great extend that you could run toward a DD at flank speed and he wouldnt know it assuming you are on the surface during your mad dash.

Originally Posted by bertockamus

You can hear surface traffic when you are just submerged (8m, but hydrophone shallower) and I suppose their hydrophones are about 2-3m down. The deeper you go, the better you can hear (notwithstanding the thermalcline, is that modeled in SH3?) because you can get away from the surface noise.

thermals are not modeled in SH3 - you are either on the surface or you are submerged.

In real life there are a number of factors affecting underwater acoustics... none of them are modeled in SH3. this is one of the games major shortcomings.

cold water, warm water, muddy water, water with high salinity, deep water, shallow water, surface disturbance, underwater currents and thermal layers etc etc

all of these things affect underwater listening gear... and NONE of them are modeled in SH3 sadly enough

[bertockamus]

Thanks GoldenRivet, although I never said that my hydrophones were underwater while I was on the surface. Unlike the exact placement on a DD, I do know where mine is

I used to always sneak up on my prey, even at night, thinking that at higher RPM they could still hear me on the surface. It is good to know that I don't have to worry about noise when closing on the surface.

I still do not fully believe that (in RL at least, maybe not as represented in SH3) a surface ship's hydrophones would not pick up a noisy diesel uboot on the surface in favorable sea state conditions, but I am willing to accept that it cannot as I really do not know enough about the subject.

[Commander Gizmo]

Other factor you might consider is that the props and engines on your uboat are much smaller and shallower than the majority of warships you would be hunting. That makes for a much smaller (and hopefully quieter) setup vs the competition. Add to that that the uboat is designed to be as quiet as possible and you have a distinct advantage, even on the surface.

Regarding your moving faster on the surface to attack: keep in mind that speed plays a not so small role in the ability of other ships to spot you. The faster you go, the more likely you are to be spotted.

[bertockamus]

Very good points.

[Sag75]

Thanks GoldenRivet for your accurate answer!

so if the demarcation is around 8 meters, the deck awash navigation could be risky..!

But, SH3 takes as depth your CG depth, right? so doesn't matter how much your bow or stern are down or up.. is it correct?


Anyway, all this talk comes from a my observation in U-47's Warship Mod. In this mod player U-boot are transformed in surface warships. Using the german DD, I'm able to hear by hydrophones (H) the other ship engines. But probably because their draft is below 8 meters... (or not?)