Can destroyer hear you on the surface?

[vballe]

I am trying to conduct a night surface attack early in the war (still 1939), but it's nearly impossible since the destroyer can hear my diesel engine while I'm surfaced. This is not realistic, right? I've tested with all the units visual on the map, and there its very clear that they just have some 70-100m sight (the dar ring around them) but they can hear my engine on full ahead on some 1600m.

Is there any way to have a "no hydrophone surface detection" mod for the DDs, similar to the "no surface hydrophone" that exist.

[KleenHippie]

I would think that the DD's being able to hear us on surface would be realistic, as from my understanding of the hydrophone (And I may be wrong here) is that the primary thing heard from any ship would be the propeller...

[oscar19681]

I noticed this before. But i,m not sure if its unrealstic. i have my doubts since i never heard of a u-boat being detected on the surface. But on the other hand a destoyer doesnt have to be submerged to use the hydrophone. and maybe they can detect a u-boat or other vessel on the surface that is outside of the convoy. But inside the convoy i would think the diesel would blend in with the rest of the engine noise of the convoy

[Sailor Steve]

If a destroyer could hear a surfaced submarine then they would also be able to hear a surface ship. I've never heard of that happening either.

[Fincuan]

I have no idea how this goes ingame, but irl there's nothing to prevent a surface unit from hearing another one. Being on the surface is not a magic ability that makes all your noise disappear.

[Dignan]

[QUOTE=vballe;1642713] but they can hear my engine on full ahead on some 1600m.
QUOTE]

You were only 1600m away? Night time or not, I think you are pushing the limits of remaining undetected at that range. Also, I believe the visual range circles on the navmap are a "suggested" or "estimated" range of visual detection by that ship. In my experience with SH4, you need to be at least 2000 to 2500m away for a night surface attack. Someone will correct me if I'm wrong.

EDIT: If you were at ahead full you were probably kicking up a pretty good bow wake too. If I understand how the AI works in this game then that definitely increases your odds of being detected.

[Bilge_Rat]

I have tested it out before and I am not sure if the AI is reacting to the sounds or the visual.

At night, against a non-alert AI, motionless or dead slow, you can come up to 500-700 meters without being spotted. However, if you are moving at full or flank, they can spot out to 1,500-2,000 meters. Are they reacting to sound or motion? its hard to say.

If you have IRAI, you can test it out using map updates on and seeing how far the visual cone of the freighter extends.

In RL, it must have been a concern, since I have read about U-Boats using electric motors on the surface so they would not be detected.

[Sailor Steve]

Originally Posted by Fincuan

I have no idea how this goes ingame, but irl there's nothing to prevent a surface unit from hearing another one. Being on the surface is not a magic ability that makes all your noise disappear.

Arguably true, but is there a single recorded instance of it actually happening? And if so, how common was it? Those are the real questions.

[Fincuan]

Passive sonars of those times weren't apparently that great, but I still reckon hearing other ships was common enough not to be worth specifically recording. In most cases they probably got a visual sighting long before coming to hydrophone range anyway.

[Jaguar]

Originally Posted by Bilge_Rat

I have tested it out before and I am not sure if the AI is reacting to the sounds or the visual.

So far I´m convinced that AI can´t hear you on the surface unless the sea is choppy. Bug or glitch, the game seems to think sub is underwatter (sometimes even the sub hydro is working), the yellow cone around DDs appears (I cheat! ). In more calm seas it´s only the dark visual cone present.

[CaptainMattJ.]

Destroyers didnt have radar at all during the war? i remember from playing SH4 that one of the radars on the U-Boat was a radar that could detect surface ships.

I guess i learn something new everyday

[kraznyi_oktjabr]

Originally Posted by CaptainMattJ.

Destroyers didnt have radar at all during the war? i remember from playing SH4 that one of the radars on the U-Boat was a radar that could detect surface ships.

I guess i learn something new everyday

They had radars during war but not in 1939. I don't remember exactly when they were introduced to escorts but I would guess 1942.

[Sailor Steve]

Originally Posted by kraznyi_oktjabr

They had radars during war but not in 1939. I don't remember exactly when they were introduced to escorts but I would guess 1942.

Absolutely correct. Actually British destroyers did start getting radar in 1938, but it was only Air Warning. The surface warning sets showed up in 1941.
http://www.navweaps.com/Weapons/WNBR_Radar.htm

[CaptainMattJ.]

Originally Posted by kraznyi_oktjabr

They had radars during war but not in 1939. I don't remember exactly when they were introduced to escorts but I would guess 1942.

well tbh there was a tiny hint of sarcasm in my statement.

I knew they had radar. I just forgot what year

[raybo]

Being ex R.N I can assure you that any ship or sub running on surface with high engine output can be detected by human ear for at lest a two miles. sound travels much farther at sea than it dose on land.