View Full Version : Engine RPMs and hydrophone speed calculation question
commandosolo2009
02-02-11, 11:18 AM
Hello skippers!
Today, I decided to convert to the much acclaimed, old-styled, sonar only attack. Now, in order to get speed for the target, with contacts on, I'd start a 10 minute monitor over the PPI and divide the range covered from start time to stop time, then do the regular maths distance/time to get his speed. Now comes the submerged problem as an arbitrary estimate is usually the case, and you end up with off the chart calculations and many misses...
Now, I wanted to ask if there was a RPM guide around here, much like RPM over speed in kts?, for trained ears to use.. I kinda like the idea of staying low and not exposing myself at all, and this is what I also hope to get your advice on.
To be exact, is there a chart or not necessarily a chart, but a rule for rpms vs speed (kts) here? And, if I put my hydrophone operator on monitor, he leaves all the targets and focuses on the warships which are naturally ahead of the convoy, so is there a way to let him monitor that specific screw on the telegraph? I guess there aint, but I'm just spitballing here..
Another thing, if he were to monitor a sole merchant, should I set the TDCPK to this bearing or do a fan spread ahead of the target?
Does anyone know the actual grading on scope, corresponding to the spread dial, meaning which periscope mark on the horizontal line corresponds to say, 5 clicks left spread?
And if someone could help me with this periscope? I cant find the markings anywhere here, and certainly its not websters mod.
Here, I want these extra periscope bearing marks:
http://i1218.photobucket.com/albums/dd414/Perch176/3668079a.jpg
So, do you guys know this?
Thanks
ETR3(SS)
02-02-11, 01:14 PM
Now, I wanted to ask if there was a RPM guide around here, much like RPM over speed in kts?, for trained ears to use.. I kinda like the idea of staying low and not exposing myself at all, and this is what I also hope to get your advice on.
To be exact, is there a chart or not necessarily a chart, but a rule for rpms vs speed (kts) here? And, if I put my hydrophone operator on monitor, he leaves all the targets and focuses on the warships which are naturally ahead of the convoy, so is there a way to let him monitor that specific screw on the telegraph? I guess there aint, but I'm just spitballing here..
Yes there is a rule. Shaft RPM heard through the hydrophones does not correlate to an exact speed of target. The best you can get is a slow, medium, or fast speed report from the operator. Besides if you could accurately count the shaft rpm you would need to classify the contact in order to determine the turns per knot ratio.
commandosolo2009
02-02-11, 02:03 PM
Yes there is a rule. Shaft RPM heard through the hydrophones does not correlate to an exact speed of target. The best you can get is a slow, medium, or fast speed report from the operator. Besides if you could accurately count the shaft rpm you would need to classify the contact in order to determine the turns per knot ratio.
but but..:oops: ...
Well here is the thing, I think most merchants do in between 5 to 12 knots, unless its a hospital ship (aka modern passenger liner), regularly doing 17 kts....
But I think its possible to count rpms either through the actual turn or the cavitation although I think you focus on a portion of the sound you hear and count how many per minute... But you're right, wish I had an answer:damn::damn:, what about the periscope thing?
If you are asking about how to use a prop turns to estimate speed in the game, it is not possible. The game is modeled too simply; only a small number of sound files are used to create the screw sounds. Someone asked this before. In RL, O'Kane used this, but I don't think it was ever considered a substitute for the usual methods; more of a supplementry method.
About the periscope index ring. I don't know where you get that. It looks like a definate improvement.
Krauter
02-03-11, 02:06 AM
On a few things. I remember listening to saft rpms. The slowest chug-chug sound that you get usually means between 5-7knts. Once they've sped up means about 11-13 knts.
Now. I forget where, but in the downloads section for Sh4 there is a Hydrophone plotter utility. What you do, take 3 hydrophone readings, spaced out say 5-10 minutes apart. Take these values and enter them into the program. Now, take the same amount of time you used for your previous bearing checks and set that as your time limit to spring to another location (you need to be stationary for your original plots). Now, once you have your new position, take a bearing check, and measure distance between the two points you had.
You know have distance, speed AOB and bearing to target. d
stoianm
02-03-11, 03:29 AM
[QUOTE=commandosolo2009;1589099]Hello skippers!
Today, I decided to convert to the much acclaimed, old-styled, sonar only attack. Now, in order to get speed for the target, with contacts on, I'd start a 10 minute monitor over the PPI and divide the range covered from start time to stop time, then do the regular maths distance/time to get his speed. Now comes the submerged problem as an arbitrary estimate is usually the case, and you end up with off the chart calculations and many misses...
Now, I wanted to ask if there was a RPM guide around here, much like RPM over speed in kts?, for trained ears to use.. I kinda like the idea of staying low and not exposing myself at all, and this is what I also hope to get your advice on.
To be exact, is there a chart or not necessarily a chart, but a rule for rpms vs speed (kts) here? And, if I put my hydrophone operator on monitor, he leaves all the targets and focuses on the warships which are naturally ahead of the convoy, so is there a way to let him monitor that specific screw on the telegraph? I guess there aint, but I'm just spitballing here..
I was looking for this ,,rev/chart'' on the net but i did not find it and if i will find i can not use in game (i play sh5) because i do not have a mod to make proper sounds file for that.
But i think the methode the krauter spoked to you is the best ever to find cource, speed and distance of a target using the hydrofone: it is the ,,4 bearings methode,,
You can download a very well made video about how you can use this methode (very well explained the ,,4 bearing methode'') and a tool that you can use to aplie this methode (the tool take away 90% from the work that you must do:D)
I uploaded a file, for a friend of mine, with this 2 things -
http://www.subsim.com/radioroom/showthread.php?t=179490 (http://www.subsim.com/radioroom/showthread.php?t=179490)
see post#46
Salute!:salute:
commandosolo2009
02-03-11, 04:24 AM
Grazie mille buddies!!
stoianm
02-03-11, 04:57 AM
Grazie mille buddies!!:up:
About rpms speed calculation i found this thread (very interesting):
http://www.subsim.com/radioroom/showthread.php?t=107303&page=4
see post #1, but it works only in sh3
Salute!:salute:
vanjast
02-03-11, 05:55 AM
Hello skippers!
Here, I want these extra periscope bearing marks:
http://i1218.photobucket.com/albums/dd414/Perch176/3668079a.jpg
You find that picture file at .../data/menu/gui/bearing.dds
You'll find references to it in .../data/menu/menu_1024_768.ini file under sections TBT/Periscope/OBSScope.. as 'compass' IIRC
:)
Moonlight
02-03-11, 09:58 AM
Isn't that the Periscope Lens Kollmorgen Graphics mod by CaptainCox?, if it is you can find it Here (http://www.subsim.com/radioroom/downloads.php?do=file&id=2865)
commandosolo2009
02-03-11, 11:47 AM
no it isnt, I'm not looking for the gasket, I'm looking for more bearing marks, like BG 120,121,122,123,124,125,....... on the upper caret
I sure like the looks of this too however I'm wondering how it looks at night, since I prefer night periscope attacks mostly because I'm harder to spot and evading the ASW is easier.
Happy Hunting!
Art
vanjast
02-04-11, 12:41 AM
no it isnt, I'm not looking for the gasket, I'm looking for more bearing marks, like BG 120,121,122,123,124,125,....... on the upper caret
If you do it like that, you'll have 'number-overload' in that you cannot make out what the bearing is. 5 degree intervals are about the best, and it's easy to work out the bearing at a glance.
There's an alternative bearing indicator mod in the download section somewhere
:)
Found the Mod = Capt Scurvy's MaxOptics.. There are different versions fo GFO, TM, and RFB AFAIK
commandosolo2009
02-04-11, 06:20 AM
If you do it like that, you'll have 'number-overload' in that you cannot make out what the bearing is. 5 degree intervals are about the best, and it's easy to work out the bearing at a glance.
There's an alternative bearing indicator mod in the download section somewhere
:)
Found the Mod = Capt Scurvy's MaxOptics.. There are different versions fo GFO, TM, and RFB AFAIK
Thanks dude! Well, I've just finished the American career.. Been quite a ride, and I'm heading to SH5... Been an honor serving on USS Balao. Cheers everybody.
SH5? See you back here in a couple weeks..... LMAO
Thanks for the name of the graphics mod vanjast.
edit - Wow, at first dial up would have been faster but after several attempts it finally downloaded in MB/sec. Patience pays! Very nice mod !!
Happy Hunting!
Art
commandosolo2009
02-04-11, 05:37 PM
back!!!! I just smashed my SH5 disc, tore the paper and broke the plastic box. Well.... You knew:shifty:
back!!!! I just smashed my SH5 disc, tore the paper and broke the plastic box. Well.... You knew:shifty:
Wow!!! That was fast!!!
You sure show no mercy!!!
:DL
.
.... You knew:shifty:
I knew....lol
Happy Hunting!
Art
commandosolo2009
02-05-11, 05:44 AM
its a piece of **it disc anyways... I'm taking a short leave to study my performance and do a bit of review on my tactics, maybe come up with a new attack method. :nope:. Bummer :o
back!!!! I just smashed my SH5 disc, tore the paper and broke the plastic box. Well.... You knew:shifty:
Well, I was wondering about SH5. I guess I don't have to wonder any more..................
commandosolo2009
02-06-11, 05:14 PM
Well, I was wondering about SH5. I guess I don't have to wonder any more..................
A BIG FAT NO
What I don't understand is that the SH5 side of the forum is always cookin'. They usually have more viewers than we do, don't they? :06:
Platapus
02-06-11, 07:18 PM
What I don't understand is that the SH5 side of the forum is always cookin'. They usually have more viewers than we do, don't they? :06:
More people stop and watch a burning building too. :D
commandosolo2009
02-06-11, 08:21 PM
More people stop and watch a burning building too. :D
Good liking to... But in this case, a bullet-riddled, gaped toppled building on fire with ppl screaming kill me, NAWWWWW!!!!!!
Well, I hope Ubisoft learns something from this.
:lost:
Unfortunately UBI may have learned not to sink any more resources into Submarine simulations for the computer and may instead concentrate on more lucrative console games.
I really like the Pacific Theatre but I know I am a minority. It will take years to mod independent games like DFTD for the Pacific and US boats.
Very sad.............. on that note:
Happy Hunting!
Art
Bilge_Rat
02-09-11, 05:37 PM
SH5 is not that bad, it just needs to mature. You can't compare it to SH4 which has been modded and refined as far as it can be pushed. It's like comparing a 10 year old Bordeaux Grand-cru to a young 2010 vintage.:arrgh!:
And if someone could help me with this periscope? I cant find the markings anywhere here, and certainly its not websters mod.
Here, I want these extra periscope bearing marks:
http://i1218.photobucket.com/albums/dd414/Perch176/3668079a.jpg
So, do you guys know this?
Thanks
that mod is "Better Scopes 1.4" which had been developped by Captain Cox and l13th4l. Very fine mod which I used for a long time:
http://www.subsim.com/radioroom/showthread.php?t=120798
http://www.subsim.com/radioroom/showthread.php?t=131981&highlight=%5BREL%5D
http://www.subsim.com/radioroom/showthread.php?t=110064&highlight=realistic+periscope
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