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

[Onkel Neal]

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]

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

[CapnScurvy]

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]

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]

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]

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).

[KaleunMarco]

thanks for replies, guys.

the problem is that when i attempt to deploy a decoy i receive a message that states 'decoys not available'. even though it is the first time i have deployed one. where can i check to see if there is a weapons count that got zeroed out somehow?

[Sniper297]

Can't find a weapons count, but testing just now I found;

1. There are 10 decoys total, launch 10 and you're out.
2. You get one load per patrol - a refit gives you full fuel, torpedoes, and ammo, but does not replenish the decoys.

Dunno why that is, but seems to be how it works.

You didn't mention damage, but in the \Data folder is a text file named zones.cfg, open that with notepad and it has all the armor ratings and hit points for assorted systems. The ones with XXI are the fleet boats, and since the German term for bubble decoys is "BOLD", I'm fairly certain that UBoldXXI is for the decoy launcher. That shows an armor level of 15 and 150 hit points, so it's fairly easy to destroy in a depth charge attack. Some systems are set up so that once destroyed they can't be repaired, so I edited that file in mine to add hit points to systems like the decoy launcher, rudder, propellers, engines, and motors. If the decoy launcher is destroyed you'll get the same "unable to launch" message.

[KaleunMarco]

ok.
will that work for US boats?

[Sniper297]

Not sure about the S class, but anything that says XXI is a fleet boat so applies to all from Porpoise class to Balao class. In the Data\Library folder is the damage effects from all the ordinance, for example DepthCharges.zon (has to be opened with Silent 3ditor since it's compiled)

MinEF = 170
MaxEF = 230
AP = 0
MinRadius = 4.5
MaxRadius = 40

What that means is a depth charge exploding within 4.5 meters will do the maximum of 230 hit points, if it's 40 meters away it will do 170 hit points damage. Since the default for the decoy launcher;

[UBoldXXI]
Multiplier=1.000000
Flotability=0.000000
HitPoints=150
Destructible=No
Armor Level=15
Critic Flotation=0.300000
Critical=No
Father=30
FloodingTime=59.999996
CargoType=None

is 150 hit points, any depth charge exploding within 40 meters of the after torpedo room will destroy the decoy launcher with a single charge. I have mine jacked up to 750 so it takes at least three close hits to destroy it.

Dunno what the "Destructible" value is for, yes or no seems to make no difference that I can tell.

Obviously when you hack something like that it's difficult to test, because you have to attract the attention of a destroyer and deliberately let him depth charge you near the system you're editing to see the results.

[KaleunMarco]

sniper,

i agree with the testing dilemma.
the things you bring up are part of the investigative process but i am not sure of what the problem is.
i am trying to figure out if my decoy launcher is even available. this is something you pointed out in a previous email. has it been destroyed in a previous patrol? how do i figure that out? (rhetorical)
see...i get the message of deploying decoys which means they are installed. then the next message is decoys not available. WTF does that mean? a. it's destroyed. b. don't have any decoys remaining. c. is the device or the ammo not defined correctly. d. something else. that is what is frustrating. the other guys, like you, are great in sharing your investigative research but testing each possibility is difficult.

if you think of anything to do with the definition of the device or the decoys themselves, please let me know.

thanks again.

[Sniper297]

Need more info for troubleshooting. Single mission, patrol, or career? What type of sub? If it's a career, ending the patrol and starting a new one should fix anything broken and restock the decoys. What version are you using 1.4 or 1.5, STEAM disc or D2D? (I still have 1.4, the D2D version) What mods do you have active?

[CapnScurvy]

i get the message of deploying decoys which means they are installed. then the next message is decoys not available. WTF does that mean?
a. it's destroyed.
b. don't have any decoys remaining.
c. is the device or the ammo not defined correctly.
d. something else.

Think of the given order to "Deploy decoys" as one action. The message back......either "Deploying decoys" or, "Decoys not available" as the reaction.

If it states "Deploying decoys".....its doing just that.

If it states "Decoys not available"......you're out.

In the following image I've got a Porpoise class sub deploying its Tenth decoy, all in one place.



The next time I ordered to deploy a decoy......"Decoys not available" showed on the text screen. Simple as that. Worked as expected.

To see if the "Decoy Launcher" is intact, check the subs "SubSystems" menu under the Aft Torpedo Room section. Scroll down the list to find it. If it's there.....no damage.....its on the boat, able to provide decoys (provided you haven't used up your supply already).

I know guys don't like to lose their "Saved" game of sinking a carrier with only one torpedo!!! BUT, when testing anything, clear out your SH4 folder found in the "Documents" folder of your computer. The game will make a new one every time you start a game without it. Don't let some error in a saved game screw up your testing.....start over with a new career. If you made a .mis file to run a test, make sure the mods (if any) are still in-game that were "activated" in-game when you made the mission. Little stuff that makes a difference in getting a good test result.

[Sniper297]

That's why I asked about mods, dunno if any of the supermods remove the decoys before a certain period in the war, or if conflict between mods will cause that. Other than having the launcher destroyed or running out of decoys, I can't think of anything else that would cause that symptom.

[merc4ulfate]

You will know they are available in home port by going to your items loadout screen where you see what radar and sonar you have on the boat. You must manually add the decoys by purchasing them with renown on the systems load out screen while in home port.

I have never seen where decoys were loaded automatically on any boat in the game no matter what year it is with the exception of starting a late career. Starting a late career with a boat designated to carry decoys will have them loaded at the start of that career I believe.