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Topic: Plunging Fire?

Ok I have a new question.

How was it determined if a gun and do plunging fire?

My vision of plunging fire is shells being shot so high they actually come down vertically onto the target. 

I imagined that this was only possible at longe range with the ships big guns.

But when I look at the gun data I find just the opposite. It the secondary and the light guns that can do plunging fire. 

For example the on the SMs Seydlitz her 11" guns cannot perform plunging fire, but her 6" and light guns can. :shock:

Is it elevation that determines this cabaility?  In which case I would be surpised the casemate guns could to this over the turret guns.

Is this a typo?

How is this so, I don't understand please help?  :?

thanks

  • From: Denver, CO
  • Registered: 2005-03-27
  • Posts: 3,578

Re: Plunging Fire?

Louie N wrote:

How was it determined if a gun and do plunging fire?
[...]
Is it elevation that determines this cabaility?  In which case I would be surpised the casemate guns could to this over the turret guns.

Is this a typo?

How is this so, I don't understand please help?  :?

Nope, no typo (as far as I'm aware).

Indeed, the gun's elevation was used as the determining factor in whether or not plunging fire was possible. However, I have lost the original data, and all I have now is the resulting "Yes/No" list for which guns can plunge and which cannot.

However, I believe the breakpoint was 30-degrees; i.e., any gun which was capable of elevating to 30 degrees or more was given the plunging fire capability.

Daniel Kast
Majestic Twelve Games
cricket@mj12games.com

mj12games's Website

  • From: Denver, CO
  • Registered: 2005-03-27
  • Posts: 3,578

Re: Plunging Fire?

cricket wrote:

However, I believe the breakpoint was 30-degrees; i.e., any gun which was capable of elevating to 30 degrees or more was given the plunging fire capability.

It's also important to remember that plunging fire was not a tactical decision on the part of a gunnery officer (i.e., No one said, "Hey-- let's do plunging fire on that target!").

Rather, plunging was the natural result of long-ranged fire... as the shells had to be lobbed higher into the air in order to cross the distance, they would come down at an oblique angle; thus the restriction that plunging fire only happens at long range.

It is theoretically possible for a gun to elevate so that its shells plunge even at point-blank range... but I don't think this was ever done... smile

Daniel Kast
Majestic Twelve Games
cricket@mj12games.com

mj12games's Website

4 Reply by Guest

  • Guest
  • Guest

Re: Plunging Fire?

Well thanks for the fast reply.  It's greatly appreciated.

So plunging fire is what I imagined it to be, so I'm not crazy. much anyway  big_smile

Did you get the guns stats from here?  I found this following the links in the back of the book.

http://www.navweaps.com/

I got my first ship painted the HMS New Zealand

  • Registered: 2005-04-02
  • Posts: 34

Re: Plunging Fire?

For example the on the SMs Seydlitz her 11" guns cannot perform plunging fire, but her 6" and light guns can. 

Is it elevation that determines this cabaility? In which case I would be surpised the casemate guns could to this over the turret guns.

While one can easily imagine the heavy guns being mounted to enable high-angle fire, the problem in WWI was fire control.  If one isn't all that sure about the range, there is a much better chance of hitting a target with a low-trajectory high-velocity shell, than by trying drop a high-trajectory shell down onto it. 

Of course, as rangefinding got better, it started to make sense to give heavy guns a greater elevation.

  • From: Denver, CO
  • Registered: 2005-03-27
  • Posts: 3,578

Re: Plunging Fire?

Louie N wrote:

Did you get the guns stats from here?  I found this following the links in the back of the book.

http://www.navweaps.com/

Yes, indeedy. Best site I've found regarding historical gun data.

Daniel Kast
Majestic Twelve Games
cricket@mj12games.com

mj12games's Website

  • From: Denver, CO
  • Registered: 2005-03-27
  • Posts: 3,578

Re: Plunging Fire?

Kevin Smith wrote:

> Did you get the guns stats from here?  I found this following
> the links in the back of the book.
> http://www.navweaps.com/
> +++
> Yes, indeedy. Best site I've found regarding historical gun data.
> ==========
>
> Really?
> Huh...
> I thought we just kinda of made all that stuff up.
> That's what I did for all the ship data anyway.
> smile

Heh... smile

Daniel Kast
Majestic Twelve Games
cricket@mj12games.com

mj12games's Website

  • Registered: 2006-01-17
  • Posts: 740

Re: Plunging Fire?

Hello everyone,

     The subject of plunging fire has been discussed.  The heavy guns on most World War One battleships had only a maximum elevation of only up to 20 degrees.  This was because if they could elevate up to 45 degrees for maximum range, they would fire so far over the horizon that spotting would be impossible even from the tops of the masts.  Thus there was no ability to use, and no need for, this extra range.  The six inch guns had a shorter overall maximum range and were able to elevate to over 30 degrees for maximum range and this inadvertently gave them "plunging fire".  That they had plunging fire was not as important to the navies of the time.  What was more important was their ability to fire as far as possible to keep hostile torpedo boats & destroyers at bay. 
     During the 1920s and 1930s when WW1 battleships were modernized, they were fitted with spotter seaplanes and their heavy guns maximum elevation was increased to up to 45 degrees for max range.  The spotter planes would radio back the fall-of-shells from the big guns when they fired way over the horizon...

Steven  Gilchrist, former US Navy Gunners Mate, Jacksonville, Fla, USA

  • From: Denver, CO
  • Registered: 2005-03-27
  • Posts: 3,578

Re: Plunging Fire?

BeowulfJB wrote:

The subject of plunging fire has been discussed.  The heavy guns on most World War One battleships had only a maximum elevation of only up to 20 degrees.

Thanks for the info!

However, elevation data is available for all guns listed in the Grand Fleets rulebook, and was used to determine whether the gun was or was not capable of plunging fire.

Obviously, we can't be completely accurate without test-firing every weapon at range (which would be fun... smile), but I am confident that we have accounted for the facts you present...

Daniel Kast
Majestic Twelve Games
cricket@mj12games.com

mj12games's Website

  • Registered: 2005-04-02
  • Posts: 34

Re: Plunging Fire?

The heavy guns on most World War One battleships had only a maximum elevation of only up to 20 degrees.  This was because if they could elevate up to 45 degrees for maximum range, they would fire so far over the horizon that spotting would be impossible even from the tops of the masts. Thus there was no ability to use, and no need for, this extra range.

This sort of leaves open the question of why the guns would be designed like that.  I mean, why not back off on the muzzle velocity, reduce wear on the barrels, fire to the horizon at an elevation of 45 degrees or so, and punch through the thin deck armor?  And in case anyone is as puzzled about this as I used to be, I'll be tacky enough to answer my own question:

While one can easily imagine the heavy guns being mounted to enable high-angle fire, the problem in WWI was fire control. If one isn't all that sure about the range, there is a much better chance of hitting a target with a low-trajectory high-velocity shell, than by trying drop a high-trajectory shell down onto it.

  • Registered: 2005-04-02
  • Posts: 34

Re: Plunging Fire?

And a year later, a fresh look at

It's also important to remember that plunging fire was not a tactical decision on the part of a gunnery officer (i.e., No one said, "Hey-- let's do plunging fire on that target!").

makes me agree that while it certainly isn't a decision a gunnery officer would make, I think it is a decision a ship (or squadron, etc.) commander would make.  If the enemy was your gun's "immune zone", you'd need to either open or close the range for your fire to be effective.  If you chose to open the range, effectively you would be saying, "Hey-- let's do plunging fire on that target!"

This is rarely an issue in Grand Fleets because it is primarily WWI and there are only three range bands.  On the other hand, using Grand Fleets' armor and penetration formulas, I think KGV(ii) is immune to Bismarck's main guns at medium range (as long as KGV(ii) isn't fool enough to turn end-on).  So, Bismarck trying to keep the range long would be a game example of saying, "Hey-- let's do plunging fire on that target!"