Coastal Defense Guns

TomD

TomD

e publius unum
This is pretty cool, it is one of only a couple of coastal defense shield guns still in existence. The gun is located at Fort Pickens National Park, an area continuously used as a coastal defense location from 1830 until after WWII. Shield guns guns date from the WWII era with this gun a 6 inch caliber (X aprox 40) with a range of 27,000 yards. There are 2 mounts like this with the other being about 50 yards away. Each gun had a crew of 25, housed and equipped in a reinforced concrete bunker below the mound visible in the background on the right of the bottom picture.

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I've seen some of the 14" guns that were taken off of outdated Battleships that were used for coastal defense, very few of them left and none in their actual location that I know of. People in the USA don't really think of coastal defense anymore.

Beautiful pictures as normal...thanks

Hovis
 
16" naval rifle - repurposed by the US Army. One was shipped to Aberdeen Proving Grounds for ballistic testing, and is now in the museum there.
http://www.navweaps.com/Weapons/WNUS_16-50_mk2_pics.htm
http://en.wikipedia.org/wiki/16_inch_Coast_Gun_M1919

Some photos of a WW2 German 15" naval rifle, used as a coast defense weapon: http://www.navweaps.com/Weapons/WNGER_15-52_skc34_pics.htm

Article about "Battery Arizona". Ever wonder where the USS Arizona's after turrets went? Now you know. http://www.eugeneleeslover.com/ENGINEERING/BATTERY-ARIZONA.pdf

Some pages about Fort Drum (the one in the Phillipines):
http://concretebattleship.vcwsg.org/
http://concretebattleship.org/
http://www.pacificwrecks.com/gun/philippines/fort_drum/index.html
http://en.wikipedia.org/wiki/Fort_Drum_(El_Fraile_Island)
 
Seen the one at Aberdeen. That is a good museum of equipment. The Anzio gun is there, the U.S. Atomic cannon is there. The stealth Tank (that's a funny one). And a lot of prototypes. I was thinking that gun was a 14" also at Aberdeen but it was back 1992 that last time I was there.

Hovis
 
TomD said:
How did the breech mechanism work? I'm aware of only two breech types used for large guns, interrupted screw and something very similar to a falling block and this doesn't seem to use either.
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From the companion page for the German 15" gun http://www.navweaps.com/Weapons/WNGER_15-52_skc34.htm :
Constructed of loose liner, A tube with four rings shrunk over it for about two-thirds of the length from the breech, a jacket shrunk over about two-thirds of the ring layer and a breech end-piece, breech block supporting piece and a horizontal sliding breech block.
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NOTE: The Germans made extensive use of the sliding breech block in heavy artillery - from the companion page, there is the following:
These guns, like most large caliber German guns, used a "fore charge" which was propellant in a silk bag, and a "main charge" which was propellant in a brass case. The brass case helped to seal the breech of the gun.
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Hope this helps.

Asa
 
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Asa Yam said:
From the companion page for the German 15" gun http://www.navweaps.com/Weapons/WNGER_15-52_skc34.htm :


NOTE: The Germans made extensive use of the sliding breech block in heavy artillery - from the companion page, there is the following:


Hope this helps.

Asa
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Thanks, that's what I meant when I said similar to a falling block, just like an old Sharps, but much bigger.

Like the breech mechanism in the picture below that I took of 120mm the main gun in a M1 tank. The breech is recessed to the bottom and would slide up to fire. Interestingly the main M1 gun is made by Rheinmetall and is a linear descendant of the famous WWII German 88. The gun photoed below is a little dusty but the tank had just been unloaded after being returned from Iraq.

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One of my dear departed " pop old dude ! " buddies [ Tom, Bob was another of these ] was a DD or DE sailor in WWII and always got a gleam in his eye when he talked about the 5"38's. I just decided to see what the heck the 38 stands for and found that Wiki has a great page on them.

http://en.wikipedia.org/wiki/5"/38_caliber_gun
 
I was a Gunners Mate Guns when in the Navy. To find the length on the barrel on a naval gun take the designation times itself. 5 inch 38 = 5X38 = 190 inches in length. 16 inch 50 = 800 inches in length.
 
FBecigneul said:
As was the case with the Maginot Line, these guns did not rotate 360 degrees.
The enemy is within.
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This one sure didn't rotate 360

Below that the USS Alabama just bristles with twin 5" X 38 mounts...

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I have never seen the guns, but I have heard Delaware used to be a huge artillery trap set for the German fleets before the first World War and that the gun emplacements were improved for the Second World War. Supposedly the German surface fleet was to be lured into range to attack the DuPont factories and then huge guns would pop up and blast them to smithereens. It never worked out that way, but it was said the guns were still there, and operational, for years. Does anyone know if there is any truth to this story, or was it made up by former coast watchers? I know the watch towers are all up and down the Delaware coast, those I have seen.
 
This is a q for the sailors. In Tom's last pic, is the upper most structure the gun director and range finder ??
 
crb said:
This is a q for the sailors. In Tom's last pic, is the upper most structure the gun director and range finder ??
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I don't know from where the ranging, bearing and corrections for the main guns was done but logically it would have been the highest point of the ship. In 1937, when the South Dakota class BB was designed, it would have been all optical. Later, in the early days of radar, don't know if the radar would plot shell splashes for corrections.

Here is a closer look at the superstructure.

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For range finding I think there were widely spaced optics in each side of horizontal rectangular sections. It looks like that is another range finder behind the stack.
 
I know this is strange but I was never on a ship. However, I do know that the earlier 16 inch mounts had an opical range finder in each turrent. Is that what is sticking out of each side of the 5 inch 38 mounts near the top? A backup in case the radar failed?
 
kansasvet said:
I know this is strange but I was never on a ship. However, I do know that the earlier 16 inch mounts had an optical range finder in each turret. Is that what is sticking out of each side of the 5 inch 38 mounts near the top? A backup in case the radar failed?
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You're talking about this feature on a triple 16" turret on the North Carolina. Obviously it's a sight but at the ranges with which these guns worked, getting high would be a big advantage.

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TomD said:
I don't know from where the ranging, bearing and corrections for the main guns was done but logically it would have been the highest point of the ship. In 1937, when the South Dakota class BB was designed, it would have been all optical. Later, in the early days of radar, don't know if the radar would plot shell splashes for corrections.

Here is a closer look at the superstructure.

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In the picture above, five rangefinder units are visible. On the top of the forward superstructure is a main battery director, composed of an optical rangefinder topped with a rangefinding radar. A similar director sits atop the aft superstructure. Additionally, three boxes topped by radars are also rangefinders - again, they contain an optical and a radar rangefinder. (There's a 4th unit on the starboard side of the forward superstructure which isn't visible.) The smaller units were intended for use with the 5" guns, but data from them could be fed into the main gunfire computer.

IIRC, US gunfire radars were used for spotting shellfire (from battleships) starting in mid-1942. By 1944, US fire control systems were sophisticated enough to allow first salvo straddles of targets at distances of 35,000 yards. (Source for the latter: http://www.combinedfleet.com/katori_t.htm .)

For some data on battleship fire control systems, see http://www.combinedfleet.com/b_fire.htm

Turret mounted rangefinders were usually installed as backup units to the main (superstructure mounted) units. Note that many navies usually removed optical rangefinders in the lower main turret(s) later in the war. In part, this was a weight savings measure, but another reason was the reduced effectivity of a rangefinder mounted at a lower height.
 
Asa Yam said:
In the picture above, five rangefinder units are visible. On the top of the forward superstructure is a main battery director, composed of an optical rangefinder topped with a rangefinding radar. A similar director sits atop the aft superstructure. Additionally, three boxes topped by radars are also rangefinders - again, they contain an optical and a radar rangefinder. (There's a 4th unit on the starboard side of the forward superstructure which isn't visible.) The smaller units were intended for use with the 5" guns, but data from them could be fed into the main gunfire computer.

IIRC, US gunfire radars were used for spotting shellfire (from battleships) starting in mid-1942. By 1944, US fire control systems were sophisticated enough to allow first salvo straddles of targets at distances of 35,000 yards. (Source for the latter: http://www.combinedfleet.com/katori_t.htm .)

For some data on battleship fire control systems, see http://www.combinedfleet.com/b_fire.htm

Turret mounted rangefinders were usually installed as backup units to the main (superstructure mounted) units. Note that many navies usually removed optical rangefinders in the lower main turret(s) later in the war. In part, this was a weight savings measure, but another reason was the reduced effectivity of a rangefinder mounted at a lower height.
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Thanks for your link. Sounds impressive even today though a Java App would possibly do it. But to maintain an over-the-horizon firing solution while in a 360 degree 27 knot turn while including corrections for sea state just impresses the hell out of me. It is exactly like shooting benchrest at a moving target at 20 miles out of the back of a pickup truck over a rough road while cutting donuts. Can you even begin to imagine?
From the link:

"The final adjusted rating also reflects the fact that American FC systems employed by far the most advanced stable vertical elements in the world. In practical terms, this meant that American vessels could keep a solution on a target even when performing radical maneuvers. In 1945 test, an American battleship (the North Carolina) was able to maintain a constant solution even when performing back to back high-speed 450-degree turns, followed by back-to-back 100-degree turns.7 This was a much better performance than other contemporary systems, and gave U.S. battleships a major tactical advantage, in that they could both shoot and maneuver, whereas their opponents could only do one or the other."
 
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