Sonar and radar usage

Fader_Berg · 07-09-09, 02:58 AM

Is it safe to use radar to spot ships, or will it just be a call for trouble? I've just merely survived an air raid in the atlantic. (Some new yellow planes, [yes, I'm new to this] which are terrifying compared to the ones around the british islands). I realy don't want to call their attention. But the atlantic is big and a sight of <=~7000 meters, practically means nothing.

I guess sonar shouldn't be used against destroyers. But how good is the precision of it, (by length to target)? Is it closer to truth than the WO? Is it only usefull in bad weather, and so on? How many pings? Does the target notice it?

How are you all using these things?

tomfon · 07-09-09, 03:52 AM

In my opinion radar doesn't help much for two reasons. First, destroyers and aircrafts can and will detect you. This means trouble for your Uboat and your crew... Second, i am not so sure about its effectiveness. In fact, i believe it can detect sh!t! By the time you start using the radar the Allied A/W will be quite effective. I think that using the hydrophone to detect a ship or a convoy underwater is much, much better cause you can maintain your stealthiness. Not to mention that the early radar versions - at least, have shorter range than the hydrophones. So, why take the risk of being detected by an airplane while hunting a convoy? Last, don't use the sonar to ping destroyers and don't use it to ping merchants which sail within a convoy. Unfortunately i don't know more details.

Jimbuna · 07-09-09, 06:54 AM

Your radar will be detected (when turned on) by sea and air assetts.

Your sonar will not.

Rafael · 07-09-09, 08:47 AM

I suggest to avoid using radar. My experience is quite bad for you and your crew. The radar range is too short and I agree with Tomfon, use your hydrophones submerged!

BdU should learn me that at school and inform me better about our bad radar system.

PavelKirilovich · 07-11-09, 12:53 AM

German radars get a bad rap during WWII for some reason. They had some systems which were quite good by the standards of the time and other systems on par with Allied and Soviet technology. And of course, a few subpar systems. The problem is not so much the technology fitted to the boat, as the platform to which the technology is fitted.

The radar horizon is pretty limited from a U-boat. You've only got the emitter a few metres above the ocean's surface and the emitter is space-constrained, the number of transmit and receive modules that can be fitted to the array is limited by the need to field a compact system. Power aperture and power aperture product is thus limited; but peak power was reasonable. The Germans did pretty well with this set, the key problem is what I mentioned earlier, it's only a few metres above the water.

The reason we see radars and lookouts stationed on the highest points of a ship is to artificially increase the distance to the horizon. It's a trigonometry thing. The higher a radar, the further it can see because geography (earth curvature) doesn't prohibit the signal from propagating back to the receivers. However, the enemy's radar warning receivers and direction finders only need to detect the signal, whereas we need to send a signal out AND get it back. Sod's law applies: the more **** you need to do, the less likely all of it is going to get done.

So what the radar does for you, in effect, is act as a "I'm over here" beacon to enemy ASW efforts. You want to run under full emissions control. Manually check every time you surface to make sure the radar operator/radio operator isn't running the radar of his own initiative. Nothing is more painful than being bounced by a hunter-killer group when your batteries badly needed a recharge and your CO2 levels are dangerously high.

It's OK to ping capitol ships with your sonar. It's not OK to ping ASW vessels with your sonar. Capitol ships are escorted by ASW vessels. The reason it's OK to ping the big gun big tonnage targets is because we don't have good shock dampening systems, sonars weren't typically fitted to large gun combatants because of space constraints and shock damage that would be caused by the gun's recoil to the system. Same reason full broadsides aren't fired: they'll shake the boat apart.

Bosje · 07-11-09, 03:13 AM

in my experience, radar is only useful in zero visibility conditions, when you know that a single merchant is out there somewhere in the rain and fog but you can't see a thing

of course, those conditions often come with 15 m/s winds which means the early crappy radar gets switched off every time the boat takes a plunge in the waves.

and unless i'm wrong, in real life those conditions were regarded as too terrible for attack operations

Leandros · 07-11-09, 05:31 AM

I find, as the war proceeds, that using the radar is not wise. However, the enemy's use of radar is of great value. Both to detect convoys as well as approaching aircrafts. To find you they necessarily must use their radar - and they do!. The aircrafts can usually be verified by their much faster approach speed. If your RWR detects two or more radar signals it usually indicates a convoy in the vicinity...! Sit tight a little while and observe the movement of the transmitting vessel and you soon have its course - and the convoy's...!

If a Swordfish approaches there is a carrier near by.........

Lt.Fillipidis · 07-11-09, 05:32 AM

From my experience, the radar can detect a destroyer before she even comes in visual contact in perfect conditions. That means more than 12k meters.
Just make sure to turn it off when you close in.

07-11-09, 06:22 AM

Quote:

Originally Posted by PavelKirilovich

German radars get a bad rap during WWII for some reason. They had some systems which were quite good by the standards of the time and other systems on par with Allied and Soviet technology. And of course, a few subpar systems. The problem is not so much the technology fitted to the boat, as the platform to which the technology is fitted.

The radar horizon is pretty limited from a U-boat. You've only got the emitter a few metres above the ocean's surface and the emitter is space-constrained, the number of transmit and receive modules that can be fitted to the array is limited by the need to field a compact system. Power aperture and power aperture product is thus limited; but peak power was reasonable. The Germans did pretty well with this set, the key problem is what I mentioned earlier, it's only a few metres above the water.

The reason we see radars and lookouts stationed on the highest points of a ship is to artificially increase the distance to the horizon. It's a trigonometry thing. The higher a radar, the further it can see because geography (earth curvature) doesn't prohibit the signal from propagating back to the receivers. However, the enemy's radar warning receivers and direction finders only need to detect the signal, whereas we need to send a signal out AND get it back. Sod's law applies: the more **** you need to do, the less likely all of it is going to get done.

So what the radar does for you, in effect, is act as a "I'm over here" beacon to enemy ASW efforts. You want to run under full emissions control. Manually check every time you surface to make sure the radar operator/radio operator isn't running the radar of his own initiative. Nothing is more painful than being bounced by a hunter-killer group when your batteries badly needed a recharge and your CO2 levels are dangerously high.

It's OK to ping capitol ships with your sonar. It's not OK to ping ASW vessels with your sonar. Capitol ships are escorted by ASW vessels. The reason it's OK to ping the big gun big tonnage targets is because we don't have good shock dampening systems, sonars weren't typically fitted to large gun combatants because of space constraints and shock damage that would be caused by the gun's recoil to the system. Same reason full broadsides aren't fired: they'll shake the boat apart.

Yes, I agree with everything you said here. But as far as I know in SH3 you can't be detected if you use a sonar to get target range or echolot to measure the depth what I realy find a big lack in realism..

Speaking about detection of noises underwater by DD's. There are couple more old issues which I find odd and unrealistic. The playing gramaphone can't be detected by ASW vessels and I think ASW vessels should be able to hear incoming torpedo sound at least in calm sea state ?

BulSoldier · 07-11-09, 11:05 AM

They could hear the torp (IRL) but you must agree that torps are rather small and i doubt it will be easy as detecting a ship.I presume the that torps are quiter than the normal merchant ships ?

07-11-09, 04:34 PM

Quote:

Originally Posted by BulSoldier

They could hear the torp (IRL) but you must agree that torps are rather small and i doubt it will be easy as detecting a ship.I presume the that torps are quiter than the normal merchant ships ?

You can clearly hear them runing on your own u-boat hydrophone so the same should go for ASW vessels, dunno how it realy was in RL, but in SH3 if you can hear it runing the enemy should be able to hear it too.

Jimbuna · 07-11-09, 05:11 PM

Quote:

Originally Posted by Contact

You can clearly hear them runing on your own u-boat hydrophone so the same should go for ASW vessels, dunno how it realy was in RL, but in SH3 if you can hear it runing the enemy should be able to hear it too.

This is where the game engine goes 'funny'.....it can see the wake of the steam torpedo but it can't hear the sound of either of the torpedo screws.

PavelKirilovich · 07-11-09, 08:11 PM

Couple comments:

i) Torpedoes can be difficult to pick up on passive sonar because the emitting source is behind a long object (e.g. the torpedo itself) and if the conditions are less than optimal (and when are they ever optimal?) you get some weird sound propagation issues, from what I understand. However, for long range shots the vessel should detect it (as the angle-on-target is large) and other ASW vessels should detect it; it's a very distinct high pitched "Screeee" noise on most fish.

ii) I like Leandros's electronic warfare technique. I use it myself. The game engine probably doesn't model this, but I do it anyways just to be safe: I run at decks awash and turn in towards the emitting signals to reduce my radar cross section. If the signal is moving quickly (airplane) I crash dive, because I skip a IXD2 at the moment and that thing takes forever and a day to get under the surface. (You can tell I'm used to my good ol' VIIC...)

iii) Bulsoldier: Size relates only to detecting with active sonar (ASDIC) arrays, not passive. If it's making noise, you can detect it on passive regardless of its size. Contact, by association I wish they'd hear me launch torpedoes. I'm limited to compressed air launches here, water-ram ejection didn't happen until fairly recently, so they should at least have some idea that someone just shot at them when conditions are reasonable. The gramophone thing always gets me; though I do like singing "Lili Marleen" while being depthcharged.

Captain Birdseye · 07-11-09, 09:30 PM

Another quick question,

Am I right to have only one guy operating both the hydrophone and radio, by having him on the radio when surfaced, and hydrophone when not?

07-12-09, 01:03 AM

Quote:

Originally Posted by PavelKirilovich

Contact, by association I wish they'd hear me launch torpedoes. I'm limited to compressed air launches here, water-ram ejection didn't happen until fairly recently, so they should at least have some idea that someone just shot at them when conditions are reasonable. The gramophone thing always gets me; though I do like singing "Lili Marleen" while being depthcharged.

The launch of a torpedo the same as door of torpedo tubes opening/closing should be also heard by hydrophone if ASW vessels crew is enough competent or elite I think. Also it should be rare event to detect you launching a torp, since sonar guy has to listen the right bearing (listening you) to trigger alarm on board and convoy around if there is one.

07-09-09, 02:58 AM	#1
Fader_Berg 中国水兵 Join Date: Jun 2009 Location: Uppland, Sweden Posts: 278 Downloads: 48 Uploads: 0	Sonar and radar usage Is it safe to use radar to spot ships, or will it just be a call for trouble? I've just merely survived an air raid in the atlantic. (Some new yellow planes, [yes, I'm new to this] which are terrifying compared to the ones around the british islands). I realy don't want to call their attention. But the atlantic is big and a sight of <=~7000 meters, practically means nothing. I guess sonar shouldn't be used against destroyers. But how good is the precision of it, (by length to target)? Is it closer to truth than the WO? Is it only usefull in bad weather, and so on? How many pings? Does the target notice it? How are you all using these things? __________________ patSH3r-developer, (https://fb.tuxxor.net) Type II junkie

07-09-09, 03:52 AM	#2
tomfon Grey Wolf Join Date: Jan 2008 Location: CK7662 Posts: 918 Downloads: 178 Uploads: 4	In my opinion radar doesn't help much for two reasons. First, destroyers and aircrafts can and will detect you. This means trouble for your Uboat and your crew... Second, i am not so sure about its effectiveness. In fact, i believe it can detect sh!t! By the time you start using the radar the Allied A/W will be quite effective. I think that using the hydrophone to detect a ship or a convoy underwater is much, much better cause you can maintain your stealthiness. Not to mention that the early radar versions - at least, have shorter range than the hydrophones. So, why take the risk of being detected by an airplane while hunting a convoy? Last, don't use the sonar to ping destroyers and don't use it to ping merchants which sail within a convoy. Unfortunately i don't know more details. __________________ "I would rather have questions that can't be answered than answers which can't be questioned." - Richard P. Feynman [1918/1988] "I've missed more than 9000 shots in my career. I've lost almost 300 games. 26 times, I've been trusted to take the game winning shot and missed. I've failed over and over and over again in my life. And that is why I succeed." - Michael Jordan Mods for SH3

07-09-09, 06:54 AM	#3
Jimbuna Chief of the Boat Join Date: Feb 2006 Location: 250 metres below the surface Posts: 190,615 Downloads: 63 Uploads: 13	Your radar will be detected (when turned on) by sea and air assetts. Your sonar will not. __________________ Wise men speak because they have something to say; Fools because they have to say something. Oh my God, not again!!

07-11-09, 12:53 AM	#5
PavelKirilovich Machinist's Mate Join Date: Nov 2007 Location: Canadian Coast Posts: 123 Downloads: 28 Uploads: 0	German radars get a bad rap during WWII for some reason. They had some systems which were quite good by the standards of the time and other systems on par with Allied and Soviet technology. And of course, a few subpar systems. The problem is not so much the technology fitted to the boat, as the platform to which the technology is fitted. The radar horizon is pretty limited from a U-boat. You've only got the emitter a few metres above the ocean's surface and the emitter is space-constrained, the number of transmit and receive modules that can be fitted to the array is limited by the need to field a compact system. Power aperture and power aperture product is thus limited; but peak power was reasonable. The Germans did pretty well with this set, the key problem is what I mentioned earlier, it's only a few metres above the water. The reason we see radars and lookouts stationed on the highest points of a ship is to artificially increase the distance to the horizon. It's a trigonometry thing. The higher a radar, the further it can see because geography (earth curvature) doesn't prohibit the signal from propagating back to the receivers. However, the enemy's radar warning receivers and direction finders only need to detect the signal, whereas we need to send a signal out AND get it back. Sod's law applies: the more **** you need to do, the less likely all of it is going to get done. So what the radar does for you, in effect, is act as a "I'm over here" beacon to enemy ASW efforts. You want to run under full emissions control. Manually check every time you surface to make sure the radar operator/radio operator isn't running the radar of his own initiative. Nothing is more painful than being bounced by a hunter-killer group when your batteries badly needed a recharge and your CO2 levels are dangerously high. It's OK to ping capitol ships with your sonar. It's not OK to ping ASW vessels with your sonar. Capitol ships are escorted by ASW vessels. The reason it's OK to ping the big gun big tonnage targets is because we don't have good shock dampening systems, sonars weren't typically fitted to large gun combatants because of space constraints and shock damage that would be caused by the gun's recoil to the system. Same reason full broadsides aren't fired: they'll shake the boat apart. __________________ Winter Garden on the North Atlantic Currently: U128 (Type IXC), U180 (Type IXD2), U198 (Type IXD2) operating in the I.O. Previously: U48 (Type VIIB), U568 (Type VIIC) [Completed 1940-1945 career in Type VIIs, in the Atlantic] Running: SH3 v1.4b w/ GWX 2.1

07-11-09, 03:13 AM	#6
Bosje Seasoned Skipper Join Date: Apr 2008 Posts: 732 Downloads: 89 Uploads: 0	in my experience, radar is only useful in zero visibility conditions, when you know that a single merchant is out there somewhere in the rain and fog but you can't see a thing of course, those conditions often come with 15 m/s winds which means the early crappy radar gets switched off every time the boat takes a plunge in the waves. and unless i'm wrong, in real life those conditions were regarded as too terrible for attack operations __________________ And when an 800-ton Uboat has you by the tits... you listen!

07-09-09, 08:47 AM	#4
Rafael Captain Join Date: Jun 2009 Location: Rotterdam - The Netherlands Posts: 514 Downloads: 22 Uploads: 7	I suggest to avoid using radar. My experience is quite bad for you and your crew. The radar range is too short and I agree with Tomfon, use your hydrophones submerged! BdU should learn me that at school and inform me better about our bad radar system.

07-11-09, 05:31 AM	#7
Leandros Seasoned Skipper Join Date: Jul 2008 Location: Stockholm Posts: 676 Downloads: 17 Uploads: 0	I find, as the war proceeds, that using the radar is not wise. However, the enemy's use of radar is of great value. Both to detect convoys as well as approaching aircrafts. To find you they necessarily must use their radar - and they do!. The aircrafts can usually be verified by their much faster approach speed. If your RWR detects two or more radar signals it usually indicates a convoy in the vicinity...! Sit tight a little while and observe the movement of the transmitting vessel and you soon have its course - and the convoy's...! If a Swordfish approaches there is a carrier near by.........

07-11-09, 05:32 AM	#8
Lt.Fillipidis Weps Join Date: Oct 2008 Location: Veria, Greece Posts: 365 Downloads: 44 Uploads: 0	From my experience, the radar can detect a destroyer before she even comes in visual contact in perfect conditions. That means more than 12k meters. Just make sure to turn it off when you close in.

07-11-09, 11:05 AM	#10
BulSoldier Samurai Navy Join Date: Oct 2007 Location: Burgas/Bulgaria Posts: 550 Downloads: 40 Uploads: 0	They could hear the torp (IRL) but you must agree that torps are rather small and i doubt it will be easy as detecting a ship.I presume the that torps are quiter than the normal merchant ships ? __________________ By the hour !

07-11-09, 08:11 PM	#13
PavelKirilovich Machinist's Mate Join Date: Nov 2007 Location: Canadian Coast Posts: 123 Downloads: 28 Uploads: 0	Couple comments: i) Torpedoes can be difficult to pick up on passive sonar because the emitting source is behind a long object (e.g. the torpedo itself) and if the conditions are less than optimal (and when are they ever optimal?) you get some weird sound propagation issues, from what I understand. However, for long range shots the vessel should detect it (as the angle-on-target is large) and other ASW vessels should detect it; it's a very distinct high pitched "Screeee" noise on most fish. ii) I like Leandros's electronic warfare technique. I use it myself. The game engine probably doesn't model this, but I do it anyways just to be safe: I run at decks awash and turn in towards the emitting signals to reduce my radar cross section. If the signal is moving quickly (airplane) I crash dive, because I skip a IXD2 at the moment and that thing takes forever and a day to get under the surface. (You can tell I'm used to my good ol' VIIC...) iii) Bulsoldier: Size relates only to detecting with active sonar (ASDIC) arrays, not passive. If it's making noise, you can detect it on passive regardless of its size. Contact, by association I wish they'd hear me launch torpedoes. I'm limited to compressed air launches here, water-ram ejection didn't happen until fairly recently, so they should at least have some idea that someone just shot at them when conditions are reasonable. The gramophone thing always gets me; though I do like singing "Lili Marleen" while being depthcharged. __________________ Winter Garden on the North Atlantic Currently: U128 (Type IXC), U180 (Type IXD2), U198 (Type IXD2) operating in the I.O. Previously: U48 (Type VIIB), U568 (Type VIIC) [Completed 1940-1945 career in Type VIIs, in the Atlantic] Running: SH3 v1.4b w/ GWX 2.1

07-11-09, 09:30 PM	#14
Captain Birdseye Watch Officer Join Date: Feb 2009 Location: Sat behind my desk at BdU tapping away on my Enigma machine. Posts: 339 Downloads: 44 Uploads: 0	Another quick question, Am I right to have only one guy operating both the hydrophone and radio, by having him on the radio when surfaced, and hydrophone when not?