Depth keeping mod?

[prowler3]

The facts:
GWX3
SH3Commander with Random Depth option running.

Can anyone tell me if there is a Mod which improves depth keeping abilities at deep depths? Here I am at 250m in my VIIC and I cannot keep from sinking at Silent Running, 2 knots speed. I am being hunted by 3 escorts but They keep finding me as I have to increase speed to maintain depth.

I have no idea if this is "realism"...could a sub not run Silent Running AND maintain depth?

Either way...I'll give up realism for a mod which allows me to maintain depth at 2 knots (Silent Running). What is the point of going deep to avoid escorts...if you have to speed up, and be detected, to keep from going to the bottom of the ocean? :hmmm:

[prowler3]

After posting this thread a couple of synapses fired off :O: and I remembered that the "crash dive" function may hurt your depth keeping abilities. I had commanded a crash dive AND changed the depth from 70m to 200m. Not sure if the crash dive itself or the depth change from default 70m caused the depth holding problems. Either way, I replayed the convoy attack and did not use the crash dive function. Instead, I commanded Flank speed and set depth at 200m...and had no problem maintaining 200m at 2 knots and silent running. I also noticed that the escorts had a much harder time "seeing" me at 2 knots compared to 2 knots after a crash dive initiation? Not sure why but I'll not be using the crash dive function again!

[PappyCain]

I have no idea if this is "realism"...could a sub not run Silent Running AND maintain depth.

You are basically shutting down your pumps when you run silent effectively decreasing your neutral bouyancy trim as you fill the bilge with water leaks. I keep an eye on that and if I have to run the pumps, I do!

:salute:

[PappyCain]

Oh! let me add this. The sim is wonderfully modeled in that yes you can hold trim (atitude) as you run a few knots at silent running BUT water will still be accumulating in the bilge and you will have to keep your bow planes angling to keep from losing desired depth-station keeping .. or you may have to blow ballast tanks to purge the sea water which is not good as the surface ships look for that. So! be watchful when you go near crush depth because you can lose your boat when the pumps are not working and you have too much sea water accumulating in the bilge weighing you down. If you have a damaged hull, or the worse! You may not be able to get out of it even at full throttle nose up. You will slide back into the abyss and implode.


:salute:

[K-61]

Does SH3 actually model bilge water accumulation? I've never seen anything in the documentation that says it does. In the old "Aces of the Deep" you would be prompted by your engineer to turn on the pumps.

[Kapt Z]

Does SH3 actually model bilge water accumulation? I've never seen anything in the documentation that says it does. In the old "Aces of the Deep" you would be prompted by your engineer to turn on the pumps.

Wondering about that as well.:hmmm:

I can't recall ever having problems maintaining depth control at 'silent' speed(ie silent running set and rpms under 100) unless I had already taken damage or was suffering the 'crash dive bug'. Never as far down as 250m though.

[PappyCain]

Perhaps I was too immersed in my immersion? Perhaps I had some hull damage? but the best way to know is run a deep drill near crush depth and gather data. In RL I know that is an issue and in game I have experienced exactly what I suggested on at least 2 patrols. The precise conditions I cannot recall and I am not a computer programmer LOL. I run RL commercial submersible ops! Keep us posted fellas and I will immerse myself in my glug glug fantasy world! LOL I love this sim!!

:salute:

PS: I have not read in the documentation either but your boat will drift in current / wind when shut down and will not hold course if you do not plot it and just use the compass - so my imagination sez she is being 'set' * by wind and waves ... (nautical term as in being carried or offset by current or wind). I have run on multi-million dollar simulators where wind and waves will cause nav issues. I believe that the brilliant programmers may have it in their script ... somewhere.

[Sailor Steve]

PS: I have not read in the documentation either but your boat will drift in current / wind when shut down
As far as I know this does not happen in the game. The wind will show a bearing when you ask for a weather report, but the smoke will always blow in the same direction and your sub will not drift at all.

and will not hold course if you do not plot it and just use the compass - so my imagination sez she is being 'set' * by wind and waves ... (nautical term as in being carried or offset by current or wind).
True, but completely wrong. In real life the helmsman will keep the heading you give him, but the boat will drift off course. This isn't usually major in over short distances, but if you're under cloudy weather for a week or more you can find yourself far from where you thought.

In the game the helmsman is an idiot and will let the boat steer itself where it wants to. If you set a heading of 315 and then go to time compression you'll see the compass drift all over the place, sometimes as far as reversing your course. Competely unrealistic.

[Twin Screws]

Here I am at 250m in my VIIC

The max depth of a VIIC was only 230m (U boat.net) as was the IXB that I am currently using, but I'm sure the specs in SHIII + GWX only state 165m.

Anyone throw a light on the discrepency ? :-?

[PappyCain]

Sailor Steve,

I have had drift in heavy seas. Just shut down your screws and you will witness this .. rather than pound the boat to death, and possibly lose a man overboard (which is not in the script but should be) my watch goes below. Most time I will ride out a storm at 60M deep and we listen to the records and play cards and fart.

Many times at my grid station I will just hang ... and not burn fuel.

As far as the helmsman and drift without a plotted course, 'auto helm' features or scripts keeping you on course are 'disabled' IMHO. Ergo I assumed the helmsman is fighting wind and current holding course while being set. Any bluewater sailor will confirm.

So either I am a daffy immersion buff :yeah: or perhaps there is code that makes the sim wind and seas very realistic - only the developers and programmers might answer that question. I do know you can and should point your boat into the sea for the dryest ride with the least pounding and risk even if it means a slight deviation in course - I do not like huge waves burying the con and watch. Again just my wacky style of immersion play.

:salute:

[K-61]

Pappy Cain, I play the same way as you describe in your sig line. This means I don't take silly chances that you can run in a game knowing you can reload. I like the pucker factor.

As to running deep, I find it impossible to run deep and silent at only one knot. At two knots or faster, I have read here that the escorts have an easier time tracking you. When I start to sink I have to goose the engines to arrest it.

[PappyCain]

Hehe - I enjoy getting out of jams as you describe. The escorts will hang until depleted, or until they have to catch up to their convoy. So I set my rudder 20 degrees and it becomes funny as they try to avoid collisions up on the surface and I circle and circle and meanwhile we are enjoying bratwurst and brown mustard, and having a talent contest using socks for puppets. As long as my boat is 100% and no damage to the pressure hull I feel ok. When there is damage, the pumps need to come on to expell water which means Adolf and the other puppets are retired to the sock drawer!

:har::haha::woot:

[prowler3]

The max depth of a VIIC was only 230m (U boat.net) as was the IXB that I am currently using, but I'm sure the specs in SHIII + GWX only state 165m.

Anyone throw a light on the discrepency ? :-?

Max depth and crush depth I believe are different?
I am using the SH3Commander specs for Crush Depth:

IIA=NSS_Uboat2A|175
IID=NSS_Uboat2D|200
IXB=NSS_Uboat9b|275
IXC=NSS_Uboat9c|275
IXC/40=NSS_Uboat9c|275
IXD2=NSS_Uboat9d2|275
VIIB=NSS_Uboat7b|250
VIIC=NSS_Uboat7c|300
VIIC/41=NSS_Uboat7c|350
VIIC/42=NSS_Uboat7c|450
XXI=NSS_Uboat21|350

[PappyCain]

"Depth ratings are primary design parameters and measures of a submarine (http://en.wikipedia.org/wiki/Submarine)'s ability to operate underwater. The depths to which submarines can dive are limited by the strengths of their hulls. As a first order approximation (http://en.wikipedia.org/wiki/First_order_approximation), each 10 meters (33 feet) of depth puts another atmosphere (1 bar, 14.7 psi, 100 kPa) of pressure on the hull, so at 300 meters (1,000 feet), the hull is supporting thirty atmospheres (30 bar, 441 psi, 3,000 kPa) of water pressure. (Note: The one atmosphere of air pressure at sea level is balanced by the roughly one atmosphere maintained inside the sub, so it does not normally strain the hull).

Design depth is the nominal depth listed in the submarine's specifications. From it the designers calculate the thickness of the hull metal, the boat's displacement (http://en.wikipedia.org/wiki/Ship_displacement), and many other related factors. Since the designers incorporate margins of error (http://en.wikipedia.org/wiki/Margin_of_error) in their calculations, crush depth of an actual vessel should be slightly deeper than its design depth.

Test depth is the maximum depth at which a submarine is permitted to operate under normal peacetime circumstances, and is tested during sea trials (http://en.wikipedia.org/wiki/Sea_trial). The test depth is set at two-thirds of the design depth for United States Navy (http://en.wikipedia.org/wiki/United_States_Navy) submarines, while the Royal Navy (http://en.wikipedia.org/wiki/Royal_Navy) sets test depth slightly deeper than half (4/7ths) of the design depth, and the German Navy (http://en.wikipedia.org/wiki/German_Navy) sets it at exactly one-half of design depth.


The maximum operating depth (popularly called the never-exceed depth) is the maximum depth at which a submarine is allowed to operate under any (e.g. battle) conditions.

Crush depth, officially called collapse depth, is the submerged depth at which a submarine's hull will collapse due to pressure. This is normally calculated; however, it is not always accurate. Submarines from many nations in World War II (http://en.wikipedia.org/wiki/World_War_II) reported being forced through crush depth, due to flooding or mechanical failure, only to have the water pumped out, or the failure repaired, and succeed in surfacing again. One of the most popular stories of this occurring was the story of U-96 (http://en.wikipedia.org/wiki/German_submarine_U-96_(1940)), in the movie Das Boot (http://en.wikipedia.org/wiki/Das_Boot). Note that these reports are not necessarily verifiable, and popular misunderstanding of the difference between test depth and collapse depth can confuse the discussion. (Planesman error sometimes causes submarines to exceed test depth by a few feet or meters during trials; note that a one-degree up-bubble on an Ohio-class boat indicates that the stern is some ten feet or three meters deeper than the bow.)

World War II German U-boats (http://en.wikipedia.org/wiki/U-boat) generally had collapse depths in the range of 200 to 280 meters (660 to 920 feet)."

source: wikipedia

[prowler3]

Pappy Cain, I play the same way as you describe in your sig line. This means I don't take silly chances that you can run in a game knowing you can reload. I like the pucker factor.

As to running deep, I find it impossible to run deep and silent at only one knot. At two knots or faster, I have read here that the escorts have an easier time tracking you. When I start to sink I have to goose the engines to arrest it.

As I related, I've found that you can run 2 knots and Silent and maintain depth...as long as you didn't do a Crash Dive. Again, I don't know if the CD boogered up because I increased my depth to 200m during the crash dive?

Default speed for Silent is 2 knots...but I could not maintain depth at 2 knots after the above Crash Dive. Doing the crash dive myself (Flank speed, set depth 200m) resulted in no problems maintaining 200m at 2 knots.

[prowler3]

"Depth ratings are primary design parameters and measures of a submarine (http://en.wikipedia.org/wiki/Submarine)'s ability to operate underwater. The depths to which submarines can dive are limited by the strengths of their hulls. As a first order approximation (http://en.wikipedia.org/wiki/First_order_approximation), each 10 meters (33 feet) of depth puts another atmosphere (1 bar, 14.7 psi, 100 kPa) of pressure on the hull, so at 300 meters (1,000 feet), the hull is supporting thirty atmospheres (30 bar, 441 psi, 3,000 kPa) of water pressure. (Note: The one atmosphere of air pressure at sea level is balanced by the roughly one atmosphere maintained inside the sub, so it does not normally strain the hull).

Design depth is the nominal depth listed in the submarine's specifications. From it the designers calculate the thickness of the hull metal, the boat's displacement (http://en.wikipedia.org/wiki/Ship_displacement), and many other related factors. Since the designers incorporate margins of error (http://en.wikipedia.org/wiki/Margin_of_error) in their calculations, crush depth of an actual vessel should be slightly deeper than its design depth.

Test depth is the maximum depth at which a submarine is permitted to operate under normal peacetime circumstances, and is tested during sea trials (http://en.wikipedia.org/wiki/Sea_trial). The test depth is set at two-thirds of the design depth for United States Navy (http://en.wikipedia.org/wiki/United_States_Navy) submarines, while the Royal Navy (http://en.wikipedia.org/wiki/Royal_Navy) sets test depth slightly deeper than half (4/7ths) of the design depth, and the German Navy (http://en.wikipedia.org/wiki/German_Navy) sets it at exactly one-half of design depth.


The maximum operating depth (popularly called the never-exceed depth) is the maximum depth at which a submarine is allowed to operate under any (e.g. battle) conditions.

Crush depth, officially called collapse depth, is the submerged depth at which a submarine's hull will collapse due to pressure. This is normally calculated; however, it is not always accurate. Submarines from many nations in World War II (http://en.wikipedia.org/wiki/World_War_II) reported being forced through crush depth, due to flooding or mechanical failure, only to have the water pumped out, or the failure repaired, and succeed in surfacing again. One of the most popular stories of this occurring was the story of U-96 (http://en.wikipedia.org/wiki/German_submarine_U-96_(1940)), in the movie Das Boot (http://en.wikipedia.org/wiki/Das_Boot). Note that these reports are not necessarily verifiable, and popular misunderstanding of the difference between test depth and collapse depth can confuse the discussion. (Planesman error sometimes causes submarines to exceed test depth by a few feet or meters during trials; note that a one-degree up-bubble on an Ohio-class boat indicates that the stern is some ten feet or three meters deeper than the bow.)

World War II German U-boats (http://en.wikipedia.org/wiki/U-boat) generally had collapse depths in the range of 200 to 280 meters (660 to 920 feet)."

source: wikipedia


Thanks for that Pappy Cain!

[Kapt Z]

To: BdU
From: Flotilla Commander, 1st Flot., Brest
Date: 15/11/41
Subject: Results of depth control test for type VIIC submarine

U-455, under command of Oblt. Dollein, left Brest enroute to grid BF 54 to conduct submerged depth control tests.

Dollein reported excellent depth control at slow speed and silent running at various depths down to 230 meters. Tests were commenced at the following depths 93, 131, 178 and 230 meters at both 100 rpms and 75 rpms. At each depth mentioned boat was easily maintained at requested depth for a period of two hours.

Tests were suspended and U-455 returned to Brest.


(Sorry guys. I tried to, but just could not replicate the 'sinking' problem you mention while at silent running/under 100 rpm. If your boats are undamaged and it's not the 'crash dive bug' I'm out of ideas as to what is causing it.)

[Twin Screws]

Thanks for the info Pappy & Kapt Z, that will help next time I need to get out of a fix. :DL

[PappyCain]

(Sorry guys. I tried to, but just could not replicate the 'sinking' problem you mention while at silent running/under 100 rpm. If your boats are undamaged and it's not the 'crash dive bug' I'm out of ideas as to what is causing it.)

Obviously your 'heads' (can, toilets) do not leak LOL. My boat at maximum operating depth may have had some minor hull damage with water intake, a small amount that was not fully pumped prior to going silent and deep. I do not recall the exact issue BUT with that said, Captain Immersion (moi) is sticking to his story! When at extreme depth, and pressurea leak can be dangerous to the point where one cannot continue at silent running and you must fire up the pumps (which I do believe are shut off when rigged for silent running).

:salute::yeah::03:

Some factoids for fun:

"It has long been known that air has weight. The weight of the atmosphere exerts a pressure of 14.7 pounds per square inch of force at sea level. This is to say that a 1 inch column of air as tall as the atmosphere, would weigh 14.7 pounds. We commonly call this 1 Atmosphere of pressure, or 1 ATM.

Water weighs considerably more than air does, so it can exert much more pressure. It only takes a 1 inch column of sea water 33 feet tall to weigh 14.7 pounds. This means that at a depth of 33 feet deep in the ocean, there is a total pressure of 29.4 pounds per square inch (psi). This would be 2 ATMs of pressure. One ATM from the air, + one ATM from the water. We call this the ambient pressure or absolute pressure.

Every additional 33 feet of sea water, will add another 14.7 pounds of pressure, or another ATM. At 66 feet we have two ATMs of water pressure plus our 1 ATM of air pressure for an absolute pressure of 3 ATM. At 99 feet our pressure is 4 ATMs etc.

Absolute pressure differs from gauge pressure. Gauge pressure would be the pressure that would show up on a gauge at this depth. A pressure gauge would start at 0 at the surface and show 14.7 psi at our depth of 33 feet. Gauge pressure would ignore the 14.7 psi of atmospheric pressure.

With a little math, we can determine the ambient pressure at any given depth. Knowing that 33 feet of sea water exerts a pressure of 14.7 lbs, it is simply a matter of dividing 14.7 by 33 to determine that sea water exerts a pressure of .445 lbs per foot of depth. Fresh water being slightly lighter, requires a depth of 34 feet to equal 1 ATM, so fresh water exerts a pressure of 14.7 divided by 34, or .432 lbs per foot of depth.

Let's then find out the absolute pressure for a depth of 50 feet of sea water. To solve this, we multiply the depth, 50, times the pressure per foot, .445. This gives us an answer of 22.25. This however would be the gauge pressure at a depth of 50 feet. To find the absolute pressure, we must add in the 14.7 psi of atmospheric pressure. 22.25 + 14.7 = 36.95 Thus the pressure for a depth of 50 feet in sea water is 36.95 pounds per square inch absolute. It is common to refer to this as "PSIA", pounds per square inch absolute."

Try to figure out the per sq. inch pressure at your crush depth for the type boat you are sailing. Make sure your intake pipe, valves, scope, antennae, bearings, hull fittings for your planes and 'head' do not leak. Do not accept a boat built on a Monday or Friday.

:yeah: LOL

[prowler3]

To: BdU
From: Flotilla Commander, 1st Flot., Brest
Date: 15/11/41
Subject: Results of depth control test for type VIIC submarine

U-455, under command of Oblt. Dollein, left Brest enroute to grid BF 54 to conduct submerged depth control tests.

Dollein reported excellent depth control at slow speed and silent running at various depths down to 230 meters. Tests were commenced at the following depths 93, 131, 178 and 230 meters at both 100 rpms and 75 rpms. At each depth mentioned boat was easily maintained at requested depth for a period of two hours.

Tests were suspended and U-455 returned to Brest.


(Sorry guys. I tried to, but just could not replicate the 'sinking' problem you mention while at silent running/under 100 rpm. If your boats are undamaged and it's not the 'crash dive bug' I'm out of ideas as to what is causing it.)

I believe my problem is the Crash Dive Bug. But...if I let it go to 70m without changing my ordered depth during the dive...will it still exhibit the bug? I will have to try that. In the original mission I ordered a crash dive then changed the depth to 200m before the CD was finished.

Anyway...thank you all for the exxcellent info!

[Kapt Z]

I believe my problem is the Crash Dive Bug. But...if I let it go to 70m without changing my ordered depth during the dive...will it still exhibit the bug? I will have to try that. In the original mission I ordered a crash dive then changed the depth to 200m before the CD was finished.

Anyway...thank you all for the exxcellent info!

If you do not interrupt the crash dive order with a new depth order you should be alright. I only order crash dive when on the surface and diving away from aircraft. Submerged I just order the depth I want and set a higher e-motor speed to get there quicker.

[Fish In The Water]

If you do not interrupt the crash dive order with a new depth order you should be alright.

This has been my experience as well, so (barring some unforeseen circumstance :03:) you should be okay.

[Gargamel]

(Hi guys!)

I have found that if I wait till i let the crash dive start to level off (around 60-65m on a 70m dive), then I don't encounter the depth control issue.

But I too only crash dive from the surface, and only set the depth on the meter, never using the 'd' key'.

Also, as to the OP, I believe the random depth option on CMD is for randomizing crush depth, and not for depth control. I think it just takes the hard number in the game and changes it to within (guess) +-5%, so you can never be truly sure how deep you can go.

[prowler3]

(Hi guys!)

I have found that if I wait till i let the crash dive start to level off (around 60-65m on a 70m dive), then I don't encounter the depth control issue.

But I too only crash dive from the surface, and only set the depth on the meter, never using the 'd' key'.

Also, as to the OP, I believe the random depth option on CMD is for randomizing crush depth, and not for depth control. I think it just takes the hard number in the game and changes it to within (guess) +-5%, so you can never be truly sure how deep you can go.

Yes, that's correct RE SH3CMD depth numbers...but 220m in a VIIC is well outside the crush depth upper randomization (in an undamaged boat, of course!).

[Gargamel]

I usually start taking damage around 220 in the VIIb im running now.

[prowler3]

I usually start taking damage around 220 in the VIIb im running now.

If you are using SH3Commander your depth in a type VIIB is 250 meters...+/- the randomization factor. I do not know what "vanilla" SH3 has for crush depths.

[Gargamel]

If you are using SH3Commander your depth in a type VIIB is 250 meters...+/- the randomization factor. I do not know what "vanilla" SH3 has for crush depths.

Yup. Started a new career tonight after my last was corrupted by spies. Went to 255 tonight.

[shr84]

(THIS IS FOR SILENT HUNTER 5)I posted it allready in an other thread but i think it fits better in this one.To hold a specific depth push strg/contr. and choose 0 m (or feet dont know i play german version)Now your boat holds the depth nearly constant.It takes a lot of time to sink.To change to a higher speed than 1 is not an option if you play with a.i. mod like me.But i know the only if you dont now better,i tried to play the same way but impossible because destroyers spot you again and again.Hope this helps in my case it works great.(This is for silent hunter 5)