The Official Star Trek Movie Forum

The Official Star Trek Movie Forum > Star Trek > General Star Trek Discussions > TV Shows > Deep Space Nine > defiant
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Display Modes
  #21  
Old 05-29-2008, 02:09 PM
Gunny1's Avatar
Gunny1 Gunny1 is offline
Lieutenant Commander
 
Join Date: Mar 2008
Posts: 831
Default

Quote:
Originally Posted by Akula2ssn View Post
As opposed to the


...It's almost identical to the Indiana class with the exception of the higher freeboard.)
...and the lack of the bow scrollwork.

...useless, ornate, essentially Victorian... but, hey - I actually kinda liked it!

__________________
XI COUNTDOWN CLOCK:

Reply With Quote
  #22  
Old 05-29-2008, 02:24 PM
Akula2ssn's Avatar
Akula2ssn Akula2ssn is offline
Commander
 
Join Date: Apr 2008
Location: Seattle
Posts: 1,454
Default

Still, it took them a little while to work out the bugs with having centerline turrets. The sheer mass of the guns caused the ship to list to one side exposing the waterline below the armor belt on the other side. They even had problems with the turrets breaking loose from the locking mechanisms in heavy seas and swinging uncontrollably from side to side. Think originally they used hydraulic rams and lead counterweights to balance the turrets. Eventually they finally gave up on the pillbox turret and went for the rectangular box turret.
__________________

"Don't confuse facts with reality."
-Robert D. Ballard

Last edited by Akula2ssn : 05-29-2008 at 02:36 PM.
Reply With Quote
  #23  
Old 05-29-2008, 02:56 PM
Gunny1's Avatar
Gunny1 Gunny1 is offline
Lieutenant Commander
 
Join Date: Mar 2008
Posts: 831
Default

Quote:
Originally Posted by Akula2ssn View Post
Still, it took them a little while to work out the bugs with having centerline turrets....
Turrets - then known as 'barbettes' - experienced many teething troubles; by the same token, the technology was thereby 'tried and true' by the day the H.M.S. Dreadnought - the first 'definitive' battleship - rolled around.

Just for comparison's sake:

(Image I wanted is un-linkable. However, see the picture below; just above the armor-belt you can see the positions that the original plans called for barbettes to be installed in...)

EDIT: Okay, look at theis picture, just above the armor-belt; you'll see the side-mounted turrets; by comparing this Japanese ship to the Texas, you can see where the same class of 'side-guns' were removed from the design...



U.S.S. 'Texas' - the last 'commisioned' Dreadnaught-class capitol ship:



Centerline 'barbettes'/turrets were, in fact almost an 'afterthought'; sailing 'ships of the line' always fired broadsides, with fore/aft armament little more that an embellishment. The weight-distribution problem you refer to comes with the OFF-center mounted turrets - with the weight of the barrel, so far out from the center of gravity, 'swinging out' one broadside without matching the other could cause the axial list you spoke off.

(The counterweights; as a mid-way measure, ships boasting off-axial barbettes had weights installed via capstan/chain. When the barrel was pointed fore/aft, the weight sat above the keel - as the weapon trained out, the chain would drag a matching weight 'off-side' the keel to counter the effect. It worked... but was hideously prone to both battle-damage and just general wear-and-tear, not to mention the havoc it made of regular bething/pasasgeway.)

Center-line was the SOLUTION to this problem. Considered as a percentage, the 'swing' of the barrel was negligible across it's traverse, in terms of center-of-gravity.

Ironically, you could consider the U.S. Navy's history that of 'make do'; just as axial main armament was a 'make do' measure for steam-powered warships; likewise when the Pacific fleet was crippled in 1941, America was forced to become a 'carrier navy', something it had never intended...
__________________
XI COUNTDOWN CLOCK:


Last edited by Gunny1 : 05-29-2008 at 03:10 PM.
Reply With Quote
  #24  
Old 05-29-2008, 03:21 PM
Akula2ssn's Avatar
Akula2ssn Akula2ssn is offline
Commander
 
Join Date: Apr 2008
Location: Seattle
Posts: 1,454
Default

Actually the Indiana class, which were the first centerline turret battleships in the USN had problems with the guns pulling the ships so far to one side that the waterline on the unengaged side was exposed. It also resulted in a reduced elevation arc of 5 degrees for the ships. During the Spanish American War, the Navy actually had to order the ships to return the guns to their underway positions when they were not firing. Eventually 28 tons of lead ballast were placed into the back of the turrets. This is all according to the book, American Battleships 1886-1923: Predreadnought Design and Construction.

I believe the off center design was more stable because while you had one turret on one side, you also had another turret on the other side of the ship. But you could only bring half your main battery to bear on a target.

When the Illinois class came about, the USN finally went away from the pillbox turret and used the "elliptical balanced turret" design that was used on the Royal Navy's Majestic class.
__________________

"Don't confuse facts with reality."
-Robert D. Ballard

Last edited by Akula2ssn : 05-29-2008 at 03:44 PM.
Reply With Quote
  #25  
Old 05-29-2008, 03:45 PM
Gunny1's Avatar
Gunny1 Gunny1 is offline
Lieutenant Commander
 
Join Date: Mar 2008
Posts: 831
Default

Quote:
Originally Posted by Akula2ssn View Post
...This is all according to the book, American Battleships 1886-1923: Predreadnought Design and Construction.
Then I respectfully submit that either you or the author misunderstood something; the key here being 'pre-Dreadnought'.

Dreadnought and post-dreadnought designs are centerline designs; as evidenced by my post regarding the Texas.

Now, look at the Indiana, with it's off-axis turrets. As I am sure you already know, the further from the center of gravity one moves, the greater effect any shift in weight has. This is a simple, unavoidable axiom. As such, centerline turrets cannot have the same effect you are mentioning; yet off-center turrets, by the same token, MUST. This is a basic scientific fact; the very foundational concept of leverage.

(Consider, if you will, a 'pry bar'. A very short one has little effect - you are too close to it's own fulcrum. The longer the bar, the more the effect, even though you are applying the same force/'weight'. On any ship worth speaking of as such, the fulcrum point is at, or very near, the central line - it is axial.)

I would be interested in seeing the original quotation for this position; as I said, it seems, prima facia, against all I know and understand, not just about ship design, but about basic science.
__________________
XI COUNTDOWN CLOCK:

Reply With Quote
  #26  
Old 05-29-2008, 03:58 PM
Akula2ssn's Avatar
Akula2ssn Akula2ssn is offline
Commander
 
Join Date: Apr 2008
Location: Seattle
Posts: 1,454
Default

Well Off-axis battleships like the Texas and Maine, had a turret on each side (port and starboard). So balancing the mass of the guns in relation to the centerline isn't a big problem. Just rotate both guns outward. The problem with the off-axis design was that only half the main battery could be trained on a target. The centerline design solved this problem, but they were still using the old turret designs derived from the old monitors.

With the centerline turrets in the Indiana class, the guns and most of the machinery is located on the forward side of the turret. Remember, these are really wide circular turrets. So when the guns are turned to one side, the mass of all the guns and machinery shift to one side and are no longer centerline. The turrets themselves were mounted on the centerline, but the guns were not. They were actually mounted just forward of the turret's axis of rotation. That's why the elliptical balanced turret design came about, because when the gun is trained to one side, the turret is actually slightly off center to balance out the weight of the guns.
__________________

"Don't confuse facts with reality."
-Robert D. Ballard

Last edited by Akula2ssn : 05-29-2008 at 04:02 PM.
Reply With Quote
  #27  
Old 05-29-2008, 04:09 PM
Gunny1's Avatar
Gunny1 Gunny1 is offline
Lieutenant Commander
 
Join Date: Mar 2008
Posts: 831
Default

Quote:
Originally Posted by Akula2ssn View Post
Well Off-axis battleships like the Texas and Maine, had a turret on each side (port and starboard). So balancing the mass of the guns in relation to the centerline isn't a problem.

AHA! - I see where we had the 'dislocation' here; I was referring to the discrepency in off-axial pre-dreadnought (PD) design: all guns, engaged or not, have to swing out, in order to maintain axial balance. (Prevent listing.) I mistook your own comments in this matter...

(I.e.; PD ships could NOT engage one enemy directly abeam, port, and another well aft, starboard - the starboard guns, in the original designs, HAD to be trained out to close to the same degree as the port ones, or the leverage effect would kick in.)

Now that we are 'on the same page', so to speak; you are referring to turret offset itself - in that, in the case of each individual turret, the guns project a certain distance 'forward', (if the turret is trained forward/aft.) There then, of course, must be a matching counterweight IN THAT TURRET at the rear; something the original barbette turrets did not have..

As example the turret-mount, itself, is still circular; but as a shot of a model shows, there is a large rear 'overhang' to match the weight of the gun-barrels themselves.



Again, Akula, I apologize for misunderstanding what you were (quite very correctly!) trying to point out. I thought you were referring to position-of-turret in overall ship design when, in fact, you were correctly describing problems in the actual 'pillbox' turret design, itself.
__________________
XI COUNTDOWN CLOCK:


Last edited by Gunny1 : 05-29-2008 at 04:12 PM.
Reply With Quote
  #28  
Old 05-29-2008, 04:15 PM
Akula2ssn's Avatar
Akula2ssn Akula2ssn is offline
Commander
 
Join Date: Apr 2008
Location: Seattle
Posts: 1,454
Default

Quote:
Originally Posted by Gunny1 View Post
As example the turret-mount, itself, is still circular; but as a shot of a model shows, there is a large rear 'overhang' to match the weight of the gun-barrels themselves.
Exactly. The problem with the first of the American centerline battleships is that the turrets were also circular just like the mounts and didn't have that overhang. They were literally just enlarged versions of the original Monitor turret. That's why the Indiana class listed so much to one side when their main batteries were trained on one side. It wasn't until the Illinois class that the USN adopted the elliptical balanced turret design which was the first turret design to incorporate that overhang.

Normally I would post schematics, which I do have. That would make describing things easier than just text. I just have no working scanner at the moment.
__________________

"Don't confuse facts with reality."
-Robert D. Ballard
Reply With Quote
  #29  
Old 05-29-2008, 04:35 PM
Gunny1's Avatar
Gunny1 Gunny1 is offline
Lieutenant Commander
 
Join Date: Mar 2008
Posts: 831
Default

Quote:
Originally Posted by Akula2ssn View Post
...That would make describing things easier than just text.

Well, here it is in text:

Imagine you are sitting in a canoe. Hold an oar 'tucked under' one arm-pit at about the halfway point. Turn left and right. This is a simulation of a modern, counterbalanced-turret design.

Next, take the same oar and hold it so that the... haft (can't use the right word, it gets asterisked out...) is against your chest. Turn right and left. This is an 'unbalanced' centerline design.

Next, hold an oar in each hand, right at the haft, oars aligned facing fore-and-aft; this is a simulation for an off-axial battleship; of course, they, being older, ALSO used 'unbalanced' guns. Now, with you holding them fore-and-aft, there's no problem.

Next, twist your wrists so that BOTH 'guns'(oars) train out at roughly the same time. Still, no real problem - the left 'gun' acts as a counter to the right 'gun'.

(BTW - this little example shows WHY, when they first went to axial turrets, it didn't occur to them to counter-balance the guns...)

Now, here's the kicker, that shows WHY axial design superseded off-axial.

Do the same thing, one oar held by the haft in each hand, facing fore and aft... now train out just ONE 'gun'...

The 'pillbox' design had an inherent flaw - but the same flaw was in both equidistant guns, and so could cancel each other out. The 'problem' with the first axial battleships was, ironically enough, the LACK of the countering flaw... (*Grin*)

With counter-balanced axial turrets, you could have Turret 1 firing fore, Turret 2 firing to port, and Turret 3 firing port-to-starboard to track a ship crossing your wake... yet, aside from the not-insignificant recoil, still maintain relative 'balance'.

So - as I missed the first time around - the 'argument' wasn't about POSITION of turret, but STYLE (balance) of the individual turrets.
__________________
XI COUNTDOWN CLOCK:

Reply With Quote
  #30  
Old 05-29-2008, 04:41 PM
Akula2ssn's Avatar
Akula2ssn Akula2ssn is offline
Commander
 
Join Date: Apr 2008
Location: Seattle
Posts: 1,454
Default

I'd have to check on this, but I think the real kicker about using the pillbox design was that it was more a result of the aesthetic tastes of the USN brass. I'll check on that again, but it wouldn't be the first time the USN chose something bad for purely stupid reasons.
__________________

"Don't confuse facts with reality."
-Robert D. Ballard
Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -8. The time now is 10:31 AM.


Forum theme courtesy of Mark Lambert
Powered by vBulletin® Version 3.6.8
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright © 2009 by Paramount Pictures. STAR TREK and all related
marks and logos are trademarks of CBS Studios Inc. All Rights Reserved.