Deck Gun Removal Mod for GW [MOD RELEASE]

[VonHelsching]

Deck Gun Removal Mod v1 *UPDATED*

by VonHelsching


It is 1943. The hunt is not as it was used to be. The Pauckenschlag (Drumbeat) operations are over. No more shelling tankers near U.S public beaches during daytime.

The deck gun is hardly used anymore. Almost all merchant ships can retaliate. They are lousy shots, but cannot risk it, Herr Kaleun. Your U-boat needs just 1-2 shells to prevent you from diving, or even worse to send you to the bottom.
Airplanes are a menace. Training and false alarms are carried out every day to squeeze every single second that can be deducted from your dive and crash dive times. Even a few seconds can make the difference...

DDs are even smarter now. It seems this Walker is actually a virus that spreads and multiplies. No dumb DDs anymore. The less agile long range boats with their poor turn radius and less underwater speed suffer the most. Even a few meters of tighter turn or a fraction of a knot can save your life...

You are one of the last Kaleuns that were allowed to keep their deck gun. From most U-boats it is removed by BdU directive; no questions asked. The time has come for you too to remove your precious auxilliary weapon...Everyone remembers your gunner, Werner Rumeninge, and his hits @ 4.500 m. that disabled a Flower Corvette with two direct hits; one in the guns and one on the captain's deck. Now, he is transferred to the BdU HQ, to be replaced with a new petty officer that can hardly load with ammo the new 3,7 cm AA Flak...

This marks the change of an era...
.......................................

Fellow Kaleuns,

I have the previlege to present you the Deck Gun Removal Mod (AKA Your Gunning Days are Over Mod). The stock game does not distinguish a u-boat with or withour deck gun, performance-wise. This mod does.

Now you can trade your deck gun with something that might contribute to saving your and your crew's life. Your u-boat becomes a little faster underwater and more agile.

The figures used are not a product of research; let me re-phrase it: It is a product of much web research and zero results, ie values were conservatively guesstimated. I am waiting for your feedback in order for this mod to become more accurate and realistic.


http://img221.imageshack.us/my.php?image=sh3img23420062132182340ss.jpg

So, without your deck gun you now have:

For the VII series (VIIB, VIIC, VIIC/41 and VIIC/42) you have:

Dive time: 2 seconds less
Turn Radius (R): 123,5 m , ie 4%-5% less than with DG
Underwater speed: + 0,4 kn

(negligable variations between VIIB and the rest +/- 1-2 meters in
turn radius, fractions of a second in dive times)


For the IX series (IXB, IXC., IXC/40)

Dive time: 2 seconds less
Turn Radius (R): 140,6 m , ie 5% less than with DG
Underwater speed: + 0,3 kn

For Typ IXD/2

Dive time: 2 seconds less
Turn Radius (R): 151,0 m , ie 4% less than with DG
Underwater speed: + 0,3 kn

This mod should be aplied only if you remove your deck gun using the SH3 Commander option (or any other means / mod I don't know). No cheating will be tolerated by the BdU. The mod is JSGME compatible. Just unzip "here" with 7zip in your MODS forler and enable via JSGME.

If you upgrade to a newer u-boat Typ, and your brand new u-boat has a DG, you should disable the mod (unload via JSGME).

This modlet / fix includes the Real Battery Life Mod for GW fix (plus XXI batery fix), and should be always applied after them. The template used was GW, but this mod may be used for the stock game without problems. Just don't install in the middle of a mission.


*Caveats*

As they say, beware of Greeks bearing gifts so:

1) Surface turn radius is also affeced by this mod. But this is useful only in evading DDs submerged. The change is so subtle, so that you will not notice it anyway. I just might save your life!

2) This is not by any means an attempt to model a 1,000 or more "features" of the game regarding the mofified physics of the u-boat once a component is added or removed from it. Changes regarding dive time turn radius and speed that would probably had resulted from changing conning towers, # of flaks, weight (related to torpedos fired), weight from remaining fuel etc.are *not* modelled. Feel free to dive into this mess.
3) Dive to periscope "P" settings tested, not crash dive. May be revised in the next version

*UPDATE* New Values

For the VII series (VIIB, VIIC, VIIC/41 and VIIC/42):

Dive time: <0,5 second less
Turn Radius (R): ~126 m , ie ~3% less than with DG
Underwater speed: + 0,3 kn

For the IX series (IXB, IXC., IXC/40)

Dive time: <0,5 second less
Turn Radius (R): ~144 m , ie 3% less than with DG
Underwater speed: + 0,2 kn

For Typ IXD/2

Dive time: <0,5 second less
Turn Radius (R): ~147 m , ie 3% less than with DG
Underwater speed: + 0,2 kn

Download link:

http://rapidshare.de/files/27702588/Deck_Gun_Removal_Mod_for_GW_v1.7z.html

I will also provide a link in my webspace for the users having problems with rapidshare.

Have fun without the DG!

Von Helsching

[U-Schultz]

Very cool!!

I will certainly give it a shot. I am glad to see that you attempted to reflect the "reduced drag" from not having a deck gun.

One question though...I did not know SH3 Commander had a feature to remove the deck gun? Where is this located in the program?

[JScones]

One question though...I did not know SH3 Commander had a feature to remove the deck gun? Where is this located in the program?
Click on the U-boat type, then select Remove|Deck gun.

[VonHelsching]

One question though...I did not know SH3 Commander had a feature to remove the deck gun? Where is this located in the program?
Click on the U-boat type, then select Remove|Deck gun.

JS,

This option is kind of hidden...Can you consider of moving it the "options" screen with a checkbox? (p l e a s e)

VH

[U-Schultz]

For me (if we are talking about the same part of the program) the submarine type, the hull number, and the patrol grid are "greyed out" and not accessible. I am refering to the screen where the Captains picture is.

[don1reed]

I'm with U-Schultz, it doesn't show up on my copy either.(v2.5.0.86)

[Observer]

Since you asked for feedback...

I'd like to first point out that I don't have any data to prove or disprove this mod, so on to my points and questions:

1. German U-boats (Type II, VII, and IX) were not generally optimized for underwater travel from a hydrodynamic point of view. The hull shape, very similar to that of conventional surface ships, was optimized instead for surface travel (obviously with an eye towards surfaced and submerged stability). It wasn't until later when submarine designers tried to optimize hulls for underwater travel (for example, but not limited to, albacore shaped hulls).

These optimized types of hulls do suffer from changes in flow across the hull that result in performance changes. A classic example is the 688 high speed turn behavior, or the loss in speed due to hull fouling (such as the "grass skirt" for those boats deployed to warm water areas such as the Med.). This type of fouling can have a significant impact on the boats performance. Also included in this optimization is the screw design.

2. How, exactly, does deck gun removal shorten the time it takes to submerge the boat? Do the ballast tanks flood faster? Does the change in buoyancy and center of gravity somehow cause the boat to submerge faster?

3. How, exactly, does the deck gun removal impact rudder efficiency and improve U-boat turn radius?

4. The increase in submerged speed you suggest is apparently due to the improvement in hull efficiency from the removal of the deck gun. While this may seem reasonable, it's probably not very likely for a number of reasons. First, U-boat hulls tend to have quite a few projections that will induce drag, items such as railings, flak guns, hand wheels on hatches, and so on. The loss of the deck gun and the subsequent improvement in hull efficiency is probably small when compared to all the other drag causing items attached to the hull. The most significant, and overlooked item is the sail. It has a much bigger impact on stability and drag than any other component. By the nature of its shape size and location, the U-boat sail is completely unoptimized from underwater travel (no smooth fairings, many projections and so on).

5. I suspect you can't find any information about the improvement in boat handling characteristics because it is negligible at best. Any improvement is speed is most likely too small to measure.

Just some thoughts with no U-boat data to substantiate...

[VonHelsching]

Since you asked for feedback...

I'd like to first point out that I don't have any data to prove or disprove this mod, so on to my points and questions:

1. German U-boats (Type II, VII, and IX) were not generally optimized for underwater travel from a hydrodynamic point of view. The hull shape, very similar to that of conventional surface ships, was optimized instead for surface travel (obviously with an eye towards surfaced and submerged stability). It wasn't until later when submarine designers tried to optimize hulls for underwater travel (for example, but not limited to, albacore shaped hulls).

These optimized types of hulls do suffer from changes in flow across the hull that result in performance changes. A classic example is the 688 high speed turn behavior, or the loss in speed due to hull fouling (such as the "grass skirt" for those boats deployed to warm water areas such as the Med.). This type of fouling can have a significant impact on the boats performance. Also included in this optimization is the screw design.

2. How, exactly, does deck gun removal shorten the time it takes to submerge the boat? Do the ballast tanks flood faster? Does the change in buoyancy and center of gravity somehow cause the boat to submerge faster?

3. How, exactly, does the deck gun removal impact rudder efficiency and improve U-boat turn radius?

4. The increase in submerged speed you suggest is apparently due to the improvement in hull efficiency from the removal of the deck gun. While this may seem reasonable, it's probably not very likely for a number of reasons. First, U-boat hulls tend to have quite a few projections that will induce drag, items such as railings, flak guns, hand wheels on hatches, and so on. The loss of the deck gun and the subsequent improvement in hull efficiency is probably small when compared to all the other drag causing items attached to the hull. The most significant, and overlooked item is the sail. It has a much bigger impact on stability and drag than any other component. By the nature of its shape size and location, the U-boat sail is completely unoptimized from underwater travel (no smooth fairings, many projections and so on).

5. I suspect you can't find any information about the improvement in boat handling characteristics because it is negligible at best. Any improvement is speed is most likely too small to measure.

Just some thoughts with no U-boat data to substantiate...

Thanks, Observer. As I said I have no data either. I have read *somewhere* that when the deck gun was removed the u-boat was faster underwater and more agile.

About the dive time: Removal of the DG equals removal of *some* drag both in the horizontal and the vertical axis. Plaing drag for the horizontal plane and *some* turbulence *should* be created between the back of the DG and the conning tower and undter the DG (between DG and hull). Just guessing. You could be right though.

These calculations require a mechanical engineering hydrodynamic study. I just don't know how much is the reduction of drag. It could be 0,1 seconds, could be 2. Just asking for feedback. It doesn't matter for me if it is 0,2 seconds; it's the psychological effect to the player.

About the turn radius: Removal of drag on the horizontal plane. 5% seems *logical*. Cannot prove it, though.

About the speed. Let's say that I've read this more times than about the agility, so the change (gain) should be greater than 0,2 knots.

If I don't get any more feedback from someone else, I am thinking of reducing the effects a little bit: Dive time 1 sec or 0 sec, Turn radius probably cannot be tuned lower than 5%, unless the .sim files accept 4 digit decimals. Speed: 0,2-0,3

Thanks for the input! :up:

[JScones]

For me (if we are talking about the same part of the program) the submarine type, the hull number, and the patrol grid are "greyed out" and not accessible. I am refering to the screen where the Captains picture is.
Are you mid patrol? Retired? Dead? If so, don't expect to be able to edit your details for obvious reasons. You can only "tinker" when in base.

[JScones]

5. I suspect you can't find any information about the improvement in boat handling characteristics because it is negligible at best. Any improvement is speed is most likely too small to measure.

Just some thoughts with no U-boat data to substantiate...
I must admit, I agree with Observer. I was surprised to see the level of change you included. BUT, I say this based on absolutely no fact, so it's just gut feeling. For example, the change in dive time is 2 seconds. This is nearly the difference between a VIIB and VIIC's default dive time. If this was the case, I would instinctively think that there'd be documentation around stating that "Kaleuns in VIIB's could get VIIC dive times by simply removing their deck gun", but I've never read such a statement.

[U-Schultz]

"Are you mid patrol? Retired? Dead? If so, don't expect to be able to edit your details for obvious reasons. You can only "tinker" when in base."

That explains it then...Thx.

[VonHelsching]

5. I suspect you can't find any information about the improvement in boat handling characteristics because it is negligible at best. Any improvement is speed is most likely too small to measure.

Just some thoughts with no U-boat data to substantiate...
I must admit, I agree with Observer. I was surprised to see the level of change you included. BUT, I say this based on absolutely no fact, so it's just gut feeling. For example, the change in dive time is 2 seconds. This is nearly the difference between a VIIB and VIIC's default dive time. If this was the case, I would instinctively think that there'd be documentation around stating that "Kaleuns in VIIB's could get VIIC dive times by simply removing their deck gun", but I've never read such a statement.

JS,

Bear in mind that the 2 seconds are for the "P" / normal dive function, as indicated in the readme. In crash dive mode, it should be less (0,5-1) sec. Havn't tested it though.

The important thing with this modlet is not the values per se, but the feeling that *something* has changed as opposed to nothing. Even if the changes in values are minute, it is an incentive.

The closest information I could get for this was from the US GUPPY submarine upgrade program. This included streamlining, removal of Deck Gun plus other upgrades. I've read this resulted in 6 knots addidional underwater speed. From these 6 knots, couldn't 0,2 be attributed to the removal of the DG? Who knows...

Any references, data is welcome. Anyone?

[JScones]

The important thing with this modlet is not the values per se, but the feeling that *something* has changed as opposed to nothing. Even if the changes in values are minute, it is an incentive.
:-? If removing the deck gun did have an effect on the submarine, then the changes should, nay must, be modelled into SH3.

However, if we're just guessing, or if the effects were essentially nil, then I don't agree with making changes just as an "incentive".

BUT:
a) I am a realism player and would rather play with no changes than guessed changes;
b) I have absolutely no idea on what impact removing the deck gun did have, apart from a view that logically it would have had some kind of impact (it's not just the weight of the gun that goes, it's the 14kg *per round* of ammunition that goes with it);
c) I am not the voice of the forum.

I did a search of the internet and found absolutely nothing. BUT I did find in one of my books details of U-553's changes to its Flak guns which created adverse handling effects. Of note is that the specs for this boat, which did not have a deck gun, were exactly the same as an equivalent VII with a deck gun. May be deliberate, may be oversight, may be a coincidental net effect. But I've got a few other books which I'll look through...

In the meantime though...can anyone with an extensive u-boat book library PLEASE help us all out here????

[VonHelsching]

b) I have absolutely no idea on what impact removing the deck gun did have, apart from a view that logically it would have had some kind of impact (it's not just the weight of the gun that goes, it's the 14kg *per round* of ammunition that goes with it);


JS,

Actually, the weight, if put in the middle of the boat would be the less affecting factor. If the weight was withing specs, would probably only affect dive time (slightly IMHO) but neither turn radius, nor the max speed. Maybe the acceleration of the boat, but this is not what I was trying to model.

*BUT* if we are comparing a IX full of torpedos in the front section and an empty IX, they should be quite different in dive time these two: Remember that in crash dive, everyone's rushing in fron for obvious reasons; to change the vertical balance! A fully loaded IX should have been quite faster in diving time. But this is also not what I was trying to model, and certainly not within the allowances of the SH3 engine.

Any submariner reading? Does GUPPY sound familiar to anyone? Guys, we need data here! Heeeeeelp!

[Observer]

b) I have absolutely no idea on what impact removing the deck gun did have, apart from a view that logically it would have had some kind of impact (it's not just the weight of the gun that goes, it's the 14kg *per round* of ammunition that goes with it);


JS,

Actually, the weight, if put in the middle of the boat would be the less affecting factor. If the weight was withing specs, would probably only affect dive time (slightly IMHO) but neither turn radius, nor the max speed. Maybe the acceleration of the boat, but this is not what I was trying to model.

*BUT* if we are comparing a IX full of torpedos in the front section and an empty IX, they should be quite different in dive time these two: Remember that in crash dive, everyone's rushing in fron for obvious reasons; to change the vertical balance! A fully loaded IX should have been quite faster in diving time. But this is also not what I was trying to model, and certainly not within the allowances of the SH3 engine.

Removal of the deck gun will have zero impact on the boat's ballast. In order to correct changes in center of buoyancy and center of gravity, lead ballast would be added and/or moved around to compensate. To summarize my feelings on this mod, deck gun removal would:

1. Have absolutely no impact on dive time, either a normal dive or a crash dive.

2. Will have absolutely no impact on turn radius, surfaced or submerged.

3. Will have such a small impact on submerged speed as to be negligible. The sail is a more significant source of underwater drag than the deck gun.

Any submariner reading?

I've already answered, though others are welcome to chime in.

[VonHelsching]

Bump * UPDATE *

After a useful discussion in the uboat.net forums (not conclusive though), I am:

a) Updating the mod with new, more conservative values. See first post.

b) Creating a "mirror" / alter ego mod (of the DG Removal) which models the additional drag caused by an upgrade to the conning tower, or ultimately the U-Flak configuration. Since I consider the U-Flak the queen of the U-boats, I will call the mod U-Flak Queen Drag :-j .

Have Fun!

VonHelsching

[Pablo]

Bump * UPDATE *

After a useful discussion in the uboat.net forums (not conclusive though), I am:

a) Updating the mod with new, more conservative values. See first post.

b) Creating a "mirror" / alter ego mod (of the DG Removal) which models the additional drag caused by an upgrade to the conning tower, or ultimately the U-Flak configuration. Since I consider the U-Flak the queen of the U-boats, I will call the mod U-Flak Queen Drag :-j .

Have Fun!

VonHelsching
Hi!

Do you have any data or hydrodynamic simulations showing the effect of drag due to deck gun, conning tower, and/or changes in flak configuration? Any source that I have found states the guns were removed to obtain a "modest" reduction in drag, but fails to mention how much this affected the u-boat's underwater speed, or the extent to which it may have offset the increased drag due to the proliferation of anti-aircraft weapons and supporting superstructure.

This seems like an good idea; unfortunately, I have found no data either on line or in books to back up any change in the way the game models a u-boats underwater performance.

Pablo

[booger2005]

What about underwater range, I haven't seen that mentioned.

I think people here are forgetting that drag increases with speed. You can't really say "hey, removing the deck gun should gain you x speed" Physics doesn't work that way. If you can get the boat to go fast enough, at some point the drag reduction will be noticed. The question is: is this point within the top speed of the boat? I would bet that at slow speed, the removal would have almost no impact. At flank ahead (7 knots), I'm not sure, but you would defanetly be more likely to see the impact. Anyway, I don't think the game engine allows you to model the impact of variable speed differences well, does it?

[VonHelsching]

Do you have any data or hydrodynamic simulations showing the effect of drag due to deck gun, conning tower, and/or changes in flak configuration? Any source that I have found states the guns were removed to obtain a "modest" reduction in drag, but fails to mention how much this affected the u-boat's underwater speed, or the extent to which it may have offset the increased drag due to the proliferation of anti-aircraft weapons and supporting superstructure.


I wish I had some data. The figures I used are common sense guesstimates. I have also been told about subtle but noticable figures and I translate this as a figure between 2% and 5%. For this version I chose 3% at least for the turn radius and for speed less than 5%.

The general idea here is not the values per se, but the psychological / gameplay effect to the player that *something* has changed, even if this is a minute change, as opposed to the stock game, where *nothing* changes.

[VonHelsching]

What about underwater range, I haven't seen that mentioned.

I think people here are forgetting that drag increases with speed. You can't really say "hey, removing the deck gun should gain you x speed" Physics doesn't work that way. If you can get the boat to go fast enough, at some point the drag reduction will be noticed. The question is: is this point within the top speed of the boat? I would bet that at slow speed, the removal would have almost no impact. At flank ahead (7 knots), I'm not sure, but you would defanetly be more likely to see the impact. Anyway, I don't think the game engine allows you to model the impact of variable speed differences well, does it?

I've done some systems engineering graduate courses some years ago, but not being of a science / engineering backgroung didn't help much apart from a gerneral "feeling" about systems. But, from what I remember, you must be right. At normal speed this should have no impact whatsoever; the effect only being visible at max speed.

The game does allow fine tuning the % of max speed per gear (speeds 1-slow to 5-flank) and this is can be easily modded. I just thought that it wasn't worth it. I mean, in speed 2-halbe vahrt the additional speed should be less than 0,1 on an IX type. The effect of fatigue of your engine room crew probably is a more significant factor in speed (or the variability of it), than this mod. Anyway, good point.

Regarding underwater range, I wish I had some more data. Would be more than happy to incorporate them.

[Mr.Fleck]

I just read in the book "Unterseebootbau" (Connstruction of U-Boats) by Ulrich Gabler that the drag of a streamlined U-Boat with a submerged displacement of 500 tons is increased by 30% if the periscope is fully extended. The drag increase was measured at 4 knots.
He doesn't mention it clearly but he must be talking about post war U-Boats with a very well designed hull, surely a submarine and not a 'Tauchboot' like the U-Boats in the second world war (except Type XXI).
Unfortunately there is not more info on this special topic in the book.

For the U-Boats we are talking about 30% would be way to much because these U-Boats are far less streamlined than modern U-Boats. But I think (just a feeling) a drag penalty for the deck gun of 3-5% seems ok for me, so the speed increase should be ok.

Cheers
Mr. Fleck