[REL] Depth charge water disturbances - Page 3

irish1958 · 03-19-11, 10:22 PM

Quote:

Originally Posted by TheDarkWraith

The game will use only one of those two depending on where the DC explodes in relation to the sub. That is why I included both of them for each kind of depth charge.
As for the hedgehogs I can make a smaller disturbance for them.

Surely somebody knows how long the effect lasts for both DC and HH.
I will look into this tomorrow and see if I can come up with some reasonable time frame. Since the DC is dropped behind the moving destroyer in the dead zone, it may last a long time, until the DD has a chance to turn and acquire the sub again. As for the hedge hogs, since they are thrown in front and to the side, and since they are many of them, the ASDIC disturbance could be worse. This is just speculation. Someone must know.

It might also vary depending upon the date in the war, as I assume the equipment improved over the years as did radar.
In the mean time, I think a time of 60+/- would make the game better. Too short and it won't help, too long and it is probably not as interesting as it may make evasion too easy.
This is a great mod and add a lot to the game. Thanks again.

Fish In The Water · 03-19-11, 11:15 PM

It's difficult to come up with specific references off the top of my head, but I do recall reading something in the range of 30 seconds. Most accounts describe the period of sonar loss as 'brief,' but few go so far as to assign an actual time frame.

One thing they do seem to agree on is that it was often tricky to reacquire contact even after the turbulence had subsided. Hence the need to develop multiple tracking tactics.

I too will look into this to see if I can find some reputable sources that help spell it out. Once again great mod, thanks for sticking with it and especially for considering community input.

Robin40 · 03-20-11, 02:13 AM

Quote:

Originally Posted by irish1958

Surely somebody knows how long the effect lasts for both DC and HH.
I will look into this tomorrow and see if I can come up with some reasonable time frame. Since the DC is dropped behind the moving destroyer in the dead zone, it may last a long time, until the DD has a chance to turn and acquire the sub again.
Thanks again.

This applies if only one DD is chasing...in a Hunter-Killer group there is at least one DD listening on hydrophones

Stiebler · 03-20-11, 05:10 AM

Times for asdic disturbance:

When escorts dropped depthcharges, they sank slowly, and exploded at different depths (e.g. some at 100m, some at 150m, for a 'bracket' of the U-boat.)

Thus the total time of disturbance was likely to be of the order of minutes, not seconds. I think Rubini's suggestion of 10 minutes was pretty good.

[To give a concrete example, when two *expert* sloops attacked U-504 almost simultaneously, at great depth, in two attacks separated by just six minutes, it required almost an hour to re-establish contact. This was in June 1943, when asdic equipment was efficient.]

Also, the whole point of the Hedgehog-discharged bombs (not depthcharges) was that they exploded only on contact with a U-boat (this is wrongly modelled in SH3), so there was never *any* disturbance in the water if they missed their target. That was why the hedgehog attack was so popular - no loss of asdic contact during the approach to the target, no loss of contact by neighbouring escorts if the bombs missed.

This is another great mod, TDW, indeed another essential mod. But times of disturbance have to be changed, and I regret to say that it is desirable to remove the addition for the hedgehogs.

Stiebler.

SquareSteelBar · 03-20-11, 05:18 AM

Quote:

Originally Posted by Stiebler

...that they exploded only on contact with a U-boat (this is wrongly modelled in SH3)...

Maybe that could be fixable...?

Gargamel · 03-20-11, 05:50 AM

Quote:

Originally Posted by SquareSteelBar

Maybe that could be fixable...?

While I have no experience in this, my guess would be that the devs just treated them as smaller, forward flung DC's, as they exhibit a lot of the same properties as DC's. Not sure how SH3 is coded, but it might entail introducing a whole new type of object in the game.

Although, if you could mix the object properties of a torpedo and a DC, you might have a HH, and then you could add the disturbance, as I'm sure it would cause that.

Just throwing that out there, as sometimes it take's an outsiders idea to spur a new approach to something.

TheDarkWraith · 03-20-11, 10:08 AM

Quote:

Originally Posted by Gargamel

While I have no experience in this, my guess would be that the devs just treated them as smaller, forward flung DC's, as they exhibit a lot of the same properties as DC's. Not sure how SH3 is coded, but it might entail introducing a whole new type of object in the game.

Although, if you could mix the object properties of a torpedo and a DC, you might have a HH, and then you could add the disturbance, as I'm sure it would cause that.

Just throwing that out there, as sometimes it take's an outsiders idea to spur a new approach to something.

I have an idea as to how this can work. Will try it and see. Hedge hogs are the same way in SH5 so they need to be corrected to work like they are supposed to

TheDarkWraith · 03-20-11, 10:30 AM

v4.0 released. See post #1 for details.

I left hedge hogs in until they can be make to function like they do/did in real life. Still working on it.

irish1958 · 03-20-11, 11:00 AM

After spending several hours investigating this topic, I can't determine how long the disturbance from a DC persists. What I did learn is that the destroyer always looses contact after an attack and it takes a while to reestablish, if it can be. As Stiebler pointed out, an hour or more was not uncommon. Another source stated that there is a one in fifteen chance of establishing contact if the correct procedures were followed but that they rarely were.
Another source stated that it is impossible for a WWII destroyer to re-establish contact with any sub traveling faster than 15 knots as it's sonar was not effective above 15 knots due to water noise from the sonar array of the destroyer. The type XXI, had it been developed, would have be devastating.
So apparently a single destroyer was not very effective against the WWII subs. If a single destroyer was attacking a sub, the tactic was to keep the sub submerged under periscope depth while allowing the convoy to escape. The depth charges were dropped set for shallow explosions to keep the sub down and unable to attack while the convoy moved on. The destroyer would then trail the convoy and to prevent the sub from surfacing and attacking.
Up until late 1942 or early 1943 (April) the US tactics were not to sink the subs but to prevent attacks on the convoy and success was determined not by how many subs were sunk, but how many ships reached port.
This changes in 1943 (for the US).
In the Pacific, the Japanese ran out of destroyers in 1944 so the US subs were unopposed in the last year of the war.
This mod is terrific and really adds to the game.

LGN1 · 03-20-11, 04:49 PM

Great work again, TDW

Thanks a lot for sharing! It's a mod for which I have been waiting a long time.

Just a small idea: it might be good to have two bolds per depth charge explosion: one with a short life time and much noise (to simulate the hydrophone's inability to track the target) and a second with longer life time, but no noise (to 'blind' the ASDIC).

Cheers, LGN1

fitzcarraldo · 03-20-11, 07:07 PM

Really great mod...Downloading now and I´ll try it after my actual patrol.

Many thanks, DW!

Best regards.

Fitzcarraldo

difool2 · 03-20-11, 07:19 PM

Quote:

Originally Posted by irish1958

Another source stated that it is impossible for a WWII destroyer to re-establish contact with any sub traveling faster than 15 knots as it's sonar was not effective above 15 knots due to water noise from the sonar array of the destroyer. The type XXI, had it been developed, would have be devastating.

I have gone flank with an XXI near Flower Corvettes, only to see them doggedly tracking me no matter how I manuever.

irish1958 · 03-20-11, 07:45 PM

Quote:

Originally Posted by difool2

I have gone flank with an XXI near Flower Corvettes, only to see them doggedly tracking me no matter how I manuever.

Limit of the game. Couldn't happen in real life until the late '50s.

Fish In The Water · 03-20-11, 08:15 PM

Quote:

Originally Posted by irish1958

After spending several hours investigating this topic, I can't determine how long the disturbance from a DC persists.

I'm afraid I'll have to concur. Online sources appear to be few and far between. What I have come up with are a number of scientific studies that exam the dispersal rate of underwater turbulence, but few of these are directly applicable to the case in hand.

I see you're now recommending individual preference in the first post, and given current conditions, I agree this would seem to be the best course.

Thanks once again for a long sought (and essential) dose of realism. Your efforts remain very much appreciated!

Myxale · 03-21-11, 03:59 AM

Wow, great stuff!
Looking back, it has been a holy grail sort of mod, for a long time.
Never thought it'll make it. OR that someone would be able to pull off.

Does that mean that soon we from the outdated KMariene will have working decoys?

At any rate, I can only agree with the earlier posters, that this is some great mod. Kudos to all involved.

And the stuff that's been released lately is amazing.
CheerS

03-20-11, 05:10 AM	#34
Stiebler Fuel Supplier Join Date: Oct 2005 Location: London, UK Posts: 1,237 Downloads: 29 Uploads: 4	Times for asdic disturbance: When escorts dropped depthcharges, they sank slowly, and exploded at different depths (e.g. some at 100m, some at 150m, for a 'bracket' of the U-boat.) Thus the total time of disturbance was likely to be of the order of minutes, not seconds. I think Rubini's suggestion of 10 minutes was pretty good. [To give a concrete example, when two expert sloops attacked U-504 almost simultaneously, at great depth, in two attacks separated by just six minutes, it required almost an hour to re-establish contact. This was in June 1943, when asdic equipment was efficient.] Also, the whole point of the Hedgehog-discharged bombs (not depthcharges) was that they exploded only on contact with a U-boat (this is wrongly modelled in SH3), so there was never any disturbance in the water if they missed their target. That was why the hedgehog attack was so popular - no loss of asdic contact during the approach to the target, no loss of contact by neighbouring escorts if the bombs missed. This is another great mod, TDW, indeed another essential mod. But times of disturbance have to be changed, and I regret to say that it is desirable to remove the addition for the hedgehogs. Stiebler. __________________ NYGM Tonnage War Mod - More than a mod: it's an experience!

03-20-11, 11:00 AM	#39
irish1958 Ocean Warrior Join Date: Apr 2005 Location: Carmel, Indiana Posts: 3,250 Downloads: 320 Uploads: 11	After spending several hours investigating this topic, I can't determine how long the disturbance from a DC persists. What I did learn is that the destroyer always looses contact after an attack and it takes a while to reestablish, if it can be. As Stiebler pointed out, an hour or more was not uncommon. Another source stated that there is a one in fifteen chance of establishing contact if the correct procedures were followed but that they rarely were. Another source stated that it is impossible for a WWII destroyer to re-establish contact with any sub traveling faster than 15 knots as it's sonar was not effective above 15 knots due to water noise from the sonar array of the destroyer. The type XXI, had it been developed, would have be devastating. So apparently a single destroyer was not very effective against the WWII subs. If a single destroyer was attacking a sub, the tactic was to keep the sub submerged under periscope depth while allowing the convoy to escape. The depth charges were dropped set for shallow explosions to keep the sub down and unable to attack while the convoy moved on. The destroyer would then trail the convoy and to prevent the sub from surfacing and attacking. Up until late 1942 or early 1943 (April) the US tactics were not to sink the subs but to prevent attacks on the convoy and success was determined not by how many subs were sunk, but how many ships reached port. This changes in 1943 (for the US). In the Pacific, the Japanese ran out of destroyers in 1944 so the US subs were unopposed in the last year of the war. This mod is terrific and really adds to the game. __________________ Irish1958 Last edited by irish1958; 03-20-11 at 07:43 PM.

03-20-11, 07:07 PM	#41
fitzcarraldo Argentinian Skipper Join Date: Jul 2009 Location: Somewhere between Buenos Aires and the Bungo Suido Posts: 5,122 Downloads: 3214 Uploads: 0	Really great mod...Downloading now and I´ll try it after my actual patrol. Many thanks, DW! Best regards. Fitzcarraldo __________________ *My subject is War, and the pity of War. The Poetry is in the pity - Wilfred Owen.*

03-21-11, 03:59 AM	#45
Myxale Admiral Join Date: Feb 2006 Location: PQ AN 25 Posts: 2,178 Downloads: 70 Uploads: 0	Wow, great stuff! Looking back, it has been a holy grail sort of mod, for a long time. Never thought it'll make it. OR that someone would be able to pull off. Does that mean that soon we from the outdated KMariene will have working decoys? At any rate, I can only agree with the earlier posters, that this is some great mod. Kudos to all involved. And the stuff that's been released lately is amazing. CheerS __________________ SH3+GWX SH5+WoS Still Sailing....still Deep

03-19-11, 11:15 PM	#32
Fish In The Water Prince of the Sea SUBSIM Welcome Committee Join Date: Jul 2009 Location: Watching over U-253 Posts: 3,527 Downloads: 98 Uploads: 2	It's difficult to come up with specific references off the top of my head, but I do recall reading something in the range of 30 seconds. Most accounts describe the period of sonar loss as 'brief,' but few go so far as to assign an actual time frame. One thing they do seem to agree on is that it was often tricky to reacquire contact even after the turbulence had subsided. Hence the need to develop multiple tracking tactics. I too will look into this to see if I can find some reputable sources that help spell it out. Once again great mod, thanks for sticking with it and especially for considering community input.

03-20-11, 10:30 AM	#38
TheDarkWraith Black Magic Join Date: Jun 2007 Posts: 11,962 Downloads: 147 Uploads: 5	v4.0 released. See post #1 for details. I left hedge hogs in until they can be make to function like they do/did in real life. Still working on it.

03-20-11, 04:49 PM	#40
LGN1 Ace of the Deep Join Date: Mar 2006 Posts: 1,138 Downloads: 147 Uploads: 12	Great work again, TDW Thanks a lot for sharing! It's a mod for which I have been waiting a long time. Just a small idea: it might be good to have two bolds per depth charge explosion: one with a short life time and much noise (to simulate the hydrophone's inability to track the target) and a second with longer life time, but no noise (to 'blind' the ASDIC). Cheers, LGN1