PDA

View Full Version : Cavitational Speeds

Eesocks
10-21-13, 10:32 AM
On the Flood and Vent Valve indicator in the Command room is a chart showing Cavitational speeds for various depths. Anyone know if this is a good guide for avoiding passive sonar or if it is even modelled in the sim?
ETR3(SS)
10-21-13, 12:04 PM
Where's that at? I don't recall seeing that anywhere. But doesn't matter much as cavitation isn't modeled in game. As far as passive sonar detection, it's based solely on shaft rpm as far as I can tell.
Bubblehead1980
10-21-13, 01:05 PM
On the Flood and Vent Valve indicator in the Command room is a chart showing Cavitational speeds for various depths. Anyone know if this is a good guide for avoiding passive sonar or if it is even modelled in the sim?


Well it's not modeled per se but speed does affect how you are detect, as does your depth. Keep it under 100 RPM's, closer to 50 , you are pretty quiet.Having silent running on will help.Depth plays in as it would at cavitation, example, I have been at 600 feet in a Balao running ahead standard at 6 knots and remained undetected by passive sonar of escorts 1800 yards away because I was deep, no cavitation there(O Kane mentions this in his book CLEAR THE BRIDGE)

Times when I was threading through and escort screen, I may go to 100 or 200 feet depending, silent running 100 rpms maybe more, depending on depth to slip inside the screen to attack.
Eesocks
10-21-13, 01:32 PM
Well it's not modeled per say but speed does affect how you are detect, as does your depth. Keep it under 100 RPM's, closer to 50 , you are pretty quiet.Having silent running on will help.Depth plays in as it would at cavitation, example, I have been at 600 feet in a Balao running ahead standard at 6 knots and remained undetected by passive sonar of escorts 1800 yards away because I was deep, no cavitation there(O Kane mentions this in his book CLEAR THE BRIDGE)


So it seems that it may be worth taking note of.


Where's that at?


It's on a metal plate on the indicators port side of command room where all the red and green lights are.
It actually shows RPM at different depths, basically the deeper you are the more RPM's you can have.
Sailor Steve
10-21-13, 03:22 PM
per say
Per say: No such word or phrase.

Per se: Latin, "in and of itself".

Before you get the wrong idea, Steve the grammar nazi has pointed that out to everyone who has ever misused that phrase on these forums. It's my absolute pet peeve. :sunny:
fireftr18
10-21-13, 06:19 PM
Is that in stock? With or without mods? Which sub, or all of them?
Bubblehead1980
10-21-13, 10:52 PM
Per say: No such word or phrase.

Per se: Latin, "in and of itself".

Before you get the wrong idea, Steve the grammar nazi has pointed that out to everyone who has ever misused that phrase on these forums. It's my absolute pet peeve. :sunny:

lol I know better, typing in a hurry happens.Thank you mein fuhrer:har:
Eesocks
10-22-13, 10:38 AM
Is that in stock? With or without mods? Which sub, or all of them?

It is in Sargo class haven't checked in other classes

TMO 2.5
ISE v3 TMO&RBF
1.5 OTC 031312 for TMO 2.5
1.5 OTC 16 to 9 aspect ratio for TMO
1.5 OTC Realistic Scopes for 16 to 9 TMO
Armistead
10-22-13, 11:08 AM
Could be the interior mod, I think by Vickers that added all the labels to the equipment...

Get a SS of it, still can't get my game loaded as of yet on my new PC, not that I've been trying lately..
Eesocks
10-22-13, 11:21 AM
Just checked on an old pc and it's not in stock or TMO 2.5 so I'm guessing it's in Improved Stock Enviroment for TMO&RBF but I don't have them on that pc so I can't check. I'm on patrol now but I'll check when I'm in port.
Rammstein0991
10-22-13, 01:08 PM
For that matter, noob question possibly but whats the red needle on the depth gauge?:06:
Admiral Halsey
10-22-13, 02:10 PM
For that matter, noob question possibly but whats the red needle on the depth gauge?:06:

If your using the 165 ft depth gauge it's your periscope depth. If you're using the 450 ft depth gauge while running the stock game it's your crush depth and you can't exceed it or you will die. If you're running a mega mod like TMO it's your test depth and you can exceed it but how deep you can go beyond it depends on hull integrity and how much of a risk taker you are.(Though most of the time you'll have to go deeper then you're comfortable with to get the destroyers off you.)
CaptBones
10-23-13, 09:05 PM
Per say: No such word or phrase.

Per se: Latin, "in and of itself".

Before you get the wrong idea, Steve the grammar nazi has pointed that out to everyone who has ever misused that phrase on these forums. It's my absolute pet peeve. :sunny:

Then I guess "irregardless" is downgraded to a non-absolute pet peeve? :haha: But, you must've gotten Bubblehead's goat by the beard, he didn't waste any time editing that post or sending you his "thank you" note!

Howsomever (can I get an "Amen!" for that one?)...I guess I must not have been very observant WRT this in either SH 3 or 4...I've always assumed (and I know what that means!) "realistic" cavitation speeds were not modeled in the games...er...I mean sims...or maybe I do mean games...what-bloody-ever!

Perhaps I'll give it a go on my next patrol, in each game, to see if I get similar evidence/results as "BH80" experienced. I'm rather sure that I'll find "no joy" in SH3, but I hope it does work semi-realistically in SH4. It'd be a nice variation on the always-workable "take her deep and keep 'em astern" with silent running set...
BigWalleye
10-23-13, 09:30 PM
Per say: No such word or phrase.

Per se: Latin, "in and of itself".

Before you get the wrong idea, Steve the grammar nazi has pointed that out to everyone who has ever misused that phrase on these forums. It's my absolute pet peeve. :sunny:

Steve, glad to see you're still keeping a taught ship! Anchors away!

Or, as we say in France: Plus saw mime day shows! (I apologize in advance to any Francophone on the forum.)
Eesocks
10-24-13, 10:59 AM
It seems like the Cavitational Speed plate was added with TMO 2.5 and having checked several different subs,only found it in the Sargo.
ETR3(SS)
10-25-13, 08:02 AM
That explains why I've never seen it then.
Bilge_Rat
10-25-13, 08:54 AM
I dont think WW2 subs could go fast enough to cavitate. However, the faster you go, the more noise you make and the farther out you can be detected. This is modeled.

The red line on the 450 foot depth gauge in the stock game is the "test depth", the official maximum diving depth of the subs according to the U.S. Navy. In game as in real life, you can go deeper. How much deeper depends on the sub and mod you are using. The U.S. Navy was more conservative than the Kriegsmarine in its calculation of the maximum safe depth.

When you crash dive, that is also the depth at which the sub will level out.
ETR3(SS)
10-25-13, 12:59 PM
Technically cavitation occurs at the surface (depth). Boat owners can see cavitation evidence on their props.
Rammstein0991
10-25-13, 02:53 PM
If your using the 165 ft depth gauge it's your periscope depth. If you're using the 450 ft depth gauge while running the stock game it's your crush depth and you can't exceed it or you will die. If you're running a mega mod like TMO it's your test depth and you can exceed it but how deep you can go beyond it depends on hull integrity and how much of a risk taker you are.(Though most of the time you'll have to go deeper then you're comfortable with to get the destroyers off you.)

Thanks :)
Eesocks
11-09-13, 07:19 PM
After an attack on a TF I went deep and slow and got soon got pinged and had some DC's dropped on me which I managed to evade. After 30 mins the 2 escorts lost contact with me but still remained over me.

I was at 450ft and Rigged for Silent and ordered Ahead Standard, which gave me 7kts in my Balao at 170 rpm, with one Escort on either side and neither of them heard me go. After a while I went to radar depth and they were still there looking for me.

I've never risked it before, but it seems like it does work under certain circumstances,