Question about activate the decoy subsystem on a US sub in SH4

Onkel Neal · 03-25-16, 12:11 PM

Hey guys, anyone have any experience or knowledge about the decoy subsystem in SH4? I got an email from Mark, and I cannot recall anything about this, maybe there's a salty skipper here who can help?

thanks
Neal

Sniper297 · 03-25-16, 04:57 PM

Function key F1 in game brings up a key command list, according to that the J key deploys a decoy.

CapnScurvy · 03-26-16, 04:41 PM

I've had a limited amount of experience with the U.S. Sub Decoy system. I know the Porpoise and Gato class subs have the decoys, I'm not sure about the other subs. There's no mention of them installed on the boat but, you will find the "Decoy Launcher" under the Aft Torpedo Room section of the SubSystem menu.

The "J" key will launch the Bubble Generator canister just forward of the screws. I believe there are a total of 8 decoy canisters. Once depleted you'll get a "No decoy available" message in the Text Screen.

Here's what one looks like under water:

As far as the decoys actually doing something by masking your sub from an enemy's sonar, or creating a "false positive" during the AI's sonar detection........I can't say that they do anything. There is nothing in the Sim.cfg file that lists the AI's sonar sensors being altered by the use of a decoy. I would think if a decoy were to aid in the AI's sonar detection capabilities one would have the ability to modify the results much like the sonars attenuation beyond the thermal layer.

As far as I can tell, there is little we can do with the decoy capabilities. It would appear they are hard coded with the odd chance that some AI sonar detection limit was added there.

============

EDIT: There are a total of 10 canisters on board. Couldn't count!?!

Sniper297 · 03-26-16, 05:44 PM

Depends on how you use them. What I do, the second the first torpedo hits there's no point in being quiet anymore since everyone knows there's a sub in the area. So I go to ahead flank, kick out a decoy, and head for the deep. Mark an X on the chart so you know where the decoy is. The bubbles last 10 minutes, so run at flank for 4 or 5 minutes, 1200-1500 yard separation from the decoy, reduce to slow speed. With the external cam on, in most cases you'll see at least one of the escorts dropping depth charges on the decoy.

The decoy alone is never enough, it has to be combined with other methods of evasion, especially going deep.

Captain Dave · 03-26-16, 09:18 PM

Reading a book on subs, there was a section on tools and tricks that were installed in 1944. " A decoy device, fired from torpedo tubes while a boat was being depth-charged, made loud noises to mislead antisubmarine vessels as to the boat's whereabouts."
Anybody know more about this?

Sniper297 · 03-27-16, 04:04 PM

Doubtful, the author might have confused the decoy launcher with a torpedo tube, many writers get details wrong. The Germans developed the first bubble generating canister launched from vertical tubes in the aft deck, they were similar to small torpedo tubes. The Brits captured a U boat, copied the bubble generator design and shared with the US in 1942. Special tubes designed just for decoys were built into the after torpedo room of fleet boats angled up and aft at 45 degrees, about 10 inches in diameter and five or six feet long, with inner and outer doors so they could be reloaded from inside.

The US Navy had a submarine simulator torpedo back in the 70s to decoy acoustic homing torpedoes, but they were classified back then. Hunt For Red Oktober described them in the mid 80s, so apparently they were declassified by then. I don't know any of the details (I had the security clearance at the time, but no "need to know" about how they operated) but I had the impression they were less than a foot in diameter and smaller than a MK48, so probably also launched from special tubes rather than regular torpedo tubes. That's just a guess, by wrapping some kind of discardable SABOT around it you COULD launch smaller things from a standard 21" torpedo tube but I don't know for sure. I was Aviation ASW and was never on an actual operational sub, only museum tours (Silversides, U-505, and a GUPPY class tour).

Ichthyos · 02-05-18, 05:02 PM

Quote:

Originally Posted by Sniper297

Depends on how you use them. What I do, the second the first torpedo hits there's no point in being quiet anymore since everyone knows there's a sub in the area.

actually, that's not true. I have sat right on the edge of a task force after having lured the destroyer screen away and dived underneath them, taken out battleships, and so long as I am just far enough away that they can't see my periscope, and I'm running 1/3 speed, nobody notices me. I have done this repeatedly, and the big capital ships do nothing but run into my torpedoes.

the key is just to lure the destroyer screens away by being VERY noisy on the surface during your long distance approach. they will bum rush you, and just before they reach visual detection range, you crash dive below the thermocline, shut your power to 1/3, and cruise right underneath them using silent running. do that for about 400 yards, then up to periscope depth, and they are running in circles behind you, while you line up your shots on the capital ships.

really, this works every time for me.

03-25-16, 12:11 PM	#1
Onkel Neal Born to Run Silent Join Date: Jan 1997 Location: Cougar Trap, Texas Posts: 21,289 Downloads: 534 Uploads: 224	Question about activate the decoy subsystem on a US sub in SH4 Hey guys, anyone have any experience or knowledge about the decoy subsystem in SH4? I got an email from Mark, and I cannot recall anything about this, maybe there's a salty skipper here who can help? thanks Neal __________________ SUBSIM - 26 Years on the Web

03-25-16, 04:57 PM	#2
Sniper297 The Old Man Join Date: Dec 2005 Location: Philadelphia Shipyard Brig Posts: 1,386 Downloads: 160 Uploads: 19	Function key F1 in game brings up a key command list, according to that the J key deploys a decoy.

03-26-16, 05:44 PM	#4
Sniper297 The Old Man Join Date: Dec 2005 Location: Philadelphia Shipyard Brig Posts: 1,386 Downloads: 160 Uploads: 19	Depends on how you use them. What I do, the second the first torpedo hits there's no point in being quiet anymore since everyone knows there's a sub in the area. So I go to ahead flank, kick out a decoy, and head for the deep. Mark an X on the chart so you know where the decoy is. The bubbles last 10 minutes, so run at flank for 4 or 5 minutes, 1200-1500 yard separation from the decoy, reduce to slow speed. With the external cam on, in most cases you'll see at least one of the escorts dropping depth charges on the decoy. The decoy alone is never enough, it has to be combined with other methods of evasion, especially going deep.

03-26-16, 09:18 PM	#5
Captain Dave Officer Join Date: Jan 2008 Location: Herriman, Utah Posts: 247 Downloads: 398 Uploads: 3	Reading a book on subs, there was a section on tools and tricks that were installed in 1944. " A decoy device, fired from torpedo tubes while a boat was being depth-charged, made loud noises to mislead antisubmarine vessels as to the boat's whereabouts." Anybody know more about this?

03-27-16, 04:04 PM	#6
Sniper297 The Old Man Join Date: Dec 2005 Location: Philadelphia Shipyard Brig Posts: 1,386 Downloads: 160 Uploads: 19	Doubtful, the author might have confused the decoy launcher with a torpedo tube, many writers get details wrong. The Germans developed the first bubble generating canister launched from vertical tubes in the aft deck, they were similar to small torpedo tubes. The Brits captured a U boat, copied the bubble generator design and shared with the US in 1942. Special tubes designed just for decoys were built into the after torpedo room of fleet boats angled up and aft at 45 degrees, about 10 inches in diameter and five or six feet long, with inner and outer doors so they could be reloaded from inside. The US Navy had a submarine simulator torpedo back in the 70s to decoy acoustic homing torpedoes, but they were classified back then. Hunt For Red Oktober described them in the mid 80s, so apparently they were declassified by then. I don't know any of the details (I had the security clearance at the time, but no "need to know" about how they operated) but I had the impression they were less than a foot in diameter and smaller than a MK48, so probably also launched from special tubes rather than regular torpedo tubes. That's just a guess, by wrapping some kind of discardable SABOT around it you COULD launch smaller things from a standard 21" torpedo tube but I don't know for sure. I was Aviation ASW and was never on an actual operational sub, only museum tours (Silversides, U-505, and a GUPPY class tour).