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Main Forums => The Roundtable => Topic started by: K Frame on July 31, 2019, 09:42:25 AM

Title: Turret Crawl on USS Iowa
Post by: K Frame on July 31, 2019, 09:42:25 AM
This is absolutely fascinating. It shows areas of the turret structure that I've never seen on any other video, and does a really good job of explaining some other things that I've always wondered about.

https://www.youtube.com/watch?v=N0D-ulUrMIo
Title: Re: Turret Crawl on USS Iowa
Post by: Brad Johnson on July 31, 2019, 09:55:46 AM
Cool!

They need image-stabilize the vid. The image jitter is extremely distracting.

Brad
Title: Re: Turret Crawl on USS Iowa
Post by: K Frame on July 31, 2019, 12:45:20 PM
And, a WW II era Navy training film on what goes on in the turret of an Iowa-class battleship. I've never seen this one before, either.

https://www.youtube.com/watch?v=0OmOQs0ziSU
Title: Re: Turret Crawl on USS Iowa
Post by: 230RN on July 31, 2019, 04:35:21 PM
Do any of them show the details of the firing mechanism?  All I can find is a shot of the open breech with the "priming hole" showing.  The rest of then just show the wiper wiping the breech face, then the closing/closed breech and the recoil.

I note they can be fired from the turret or from the ship's control center (which presumes electrically), so what gives?

I'd like to see them loading the firing cartridge and what that mechanism is like.... an old Mauser bolt action :), a falling block mechanism, or what?  You know, details, like, do they just use a screwdriver to extract the fired priming case?  Skipped over details !

Dumb Terry
Title: Re: Turret Crawl on USS Iowa
Post by: Hawkmoon on July 31, 2019, 09:52:50 PM
Do any of them show the details of the firing mechanism?  All I can find is a shot of the open breech with the "priming hole" showing.  The rest of then just show the wiper wiping the breech face, then the closing/closed breech and the recoil.

I note they can be fired from the turret or from the ship's control center (which presumes electrically), so what gives?

I'd like to see them loading the firing cartridge and what that mechanism is like.... an old Mauser bolt action :), a falling block mechanism, or what?  You know, details, like, do they just use a screwdriver to extract the fired priming case?  Skipped over details !

Dumb Terry

Firing was shown in the movie Under Siege, but I don't know how accurate it is:

https://www.youtube.com/watch?v=TxRBP2ZKUZY
Title: Re: Turret Crawl on USS Iowa
Post by: charby on July 31, 2019, 10:55:27 PM
And, a WW II era Navy training film on what goes on in the turret of an Iowa-class battleship. I've never seen this one before, either.

https://www.youtube.com/watch?v=0OmOQs0ziSU

Says 1955 in the beginning, probably from the Iowa was recommissioned from 51-58.
Title: Re: Turret Crawl on USS Iowa
Post by: 230RN on August 01, 2019, 07:55:56 AM
Firing was shown in the movie Under Siege, but I don't know how accurate it is:

https://www.youtube.com/watch?v=TxRBP2ZKUZY

That one still doesn't reveal the details of that priming step I hunger for.  Oh, well.  I guess I'll just have to dismiss it as another mystery of life.   Like where in the turret do they even keep those priming cartridges... in someone's pocket?

My plea sounds kind of dumb, but I expect it will turn out to be one of those, "but just everyone knows that, you dummy !"

You can just barely make out the flash hole in this pic, but that doesn't help.

http://www.navweaps.com/Weapons/WNUS_16-50_mk7_breech_plug_pic.jpg

Here's "stuff" at the back end of some gun, but still not helpful.

http://www.williammaloney.com/Aviation/AberdeenUSArmyOrdinanceMuseum/HeavyArtillery/16InchCoastalDefenseGun/images/07US16InchGunBreech.jpg

Dumb Terry
Title: Re: Turret Crawl on USS Iowa
Post by: K Frame on August 01, 2019, 08:05:30 AM
Do any of them show the details of the firing mechanism?  All I can find is a shot of the open breech with the "priming hole" showing.  The rest of then just show the wiper wiping the breech face, then the closing/closed breech and the recoil.

I note they can be fired from the turret or from the ship's control center (which presumes electrically), so what gives?

I'd like to see them loading the firing cartridge and what that mechanism is like.... an old Mauser bolt action :), a falling block mechanism, or what?  You know, details, like, do they just use a screwdriver to extract the fired priming case?  Skipped over details !

Dumb Terry


The primer was the same type of primer used by the Army in its heavy guns, essentially a rifle-sized brass cartridge that could be fired either electrically or mechanically. These are supposedly pictures of standard primers still in use in the Army for its heavy guns and apparently the same type used in the Iowas and other BBs.

(https://qph.fs.quoracdn.net/main-qimg-fcced62516ba184afab9fd76dadb334f)

Unfortunately, there is precious little that I can find in the way of illustrations of the primer mechanism proper, but I'm pretty sure that there was no real way to consistently fire them mechanically. It's a given that they would be electrically fired, either from a central control station or from the turret officer's position. In the turret of a battleship, with the gun elevated, there simply isn't a lot of room to allow for lanyard firing.

I suppose in an emergency or a unique situation they could lay the at minimal elevation and mechanically fire.

This illustration shows the basics of the DeBange breech mechanism (interrupted screw) that was used on just about every large gun in most navies (German navy excepted).

(https://pwencycl.kgbudge.com/images/G/u/Gun_Specifications__debange_full.jpg)

It doesn't really go into specifics of how the priming mechanism worked, but it gives some ideas. That, I think, shows the general layout for a percussion fired gun, though, not electrically fired.

This is a video of the breech of a 15" naval gun being swung closed. It's British, from one of the WW I era Queen Elizabeths, but if you pause the video about 7 to 8 seconds in you can see some of the apparatus involved in the priming mechanism.

https://www.youtube.com/watch?v=1-qsv5tZm5M

I THINK that the British guns were electrically fired, but because they were side swing breeches, instead of the standard American drop down of the later US ships, they could be mechanically fired a bit more, but there still wasn't a lot of room in any of those turrets.

There are some pictures of the interior of the USS Texas (contemporary and very similar to the QEs) showing how tight the gun rooms were: https://www.modelboatmayhem.co.uk/forum/index.php?topic=14063.0

Note also that at that time the US was employing side swing breeches, not drop downs.


This is the very best picture I've been able to find of an Iowa class gun with the breech closed.

(https://i.pinimg.com/originals/13/d7/4a/13d74ab2639fd7fe1d6a01113b457f5b.jpg)

As you can see, there's not a lot there to suggest that there was any sort of mechanical firing mechanism.

From that picture it would simply appear that there's some sort of cover that's turned over the primer after it's inserted and that creates the electrical connections.


Finally, there are some more illustrations here on this page. Lots of VERY interesting information, some related to the subject at hand, some not, but all very interesting to go over. Some of the illustrations show period illustrations of the Iowa-class breech mechanism.

https://eugeneleeslover.com/USNAVY/GUN-BARL-CONSTRUCTION-1.html


Title: Re: Turret Crawl on USS Iowa
Post by: brimic on August 01, 2019, 08:08:25 AM
Do any of them show the details of the firing mechanism?  All I can find is a shot of the open breech with the "priming hole" showing.  The rest of then just show the wiper wiping the breech face, then the closing/closed breech and the recoil.

I note they can be fired from the turret or from the ship's control center (which presumes electrically), so what gives?

I'd like to see them loading the firing cartridge and what that mechanism is like.... an old Mauser bolt action :), a falling block mechanism, or what?  You know, details, like, do they just use a screwdriver to extract the fired priming case?  Skipped over details !

Dumb Terry

Just from what I can recall ready a Navy manual from the 1940s as a kid that belonged to my great uncle- the guns use an electrical fuse.
There is no cartridge- just various shells plus varying powder charges that get packed behind them.
Title: Re: Turret Crawl on USS Iowa
Post by: K Frame on August 01, 2019, 08:08:35 AM
"Firing was shown in the movie Under Siege, but I don't know how accurate it is:"

From what I can tell, the steps that they were showing were actually fairly accurate.
Title: Re: Turret Crawl on USS Iowa
Post by: K Frame on August 01, 2019, 08:10:50 AM
"Just from what I can recall ready a Navy manual from the 1940s as a kid that belonged to my great uncle- the guns use an electrical fuse.
There is no cartridge- just various shells plus varying powder charges that get packed behind them."

Incorrect. The primer was an actual cartridge such as the one that I showed in my previous post.

There are some videos on Youtube that show Korean-war era Army heavy artillery, and one of the things shown is evidently the priming step. I came across it last night, but I'm having trouble finding it again.
Title: Re: Turret Crawl on USS Iowa
Post by: K Frame on August 01, 2019, 08:13:55 AM
OK, there's some more information here from a Quora thread, including the primer picture I linked in AND a link to the Korean war Army artillery video: https://youtu.be/lPEI6pQc4Sc


Here's the actual Quora discussion: https://www.quora.com/On-the-big-guns-i-e-16-inch-on-battleships-what-ignited-the-powder
Title: Re: Turret Crawl on USS Iowa
Post by: 230RN on August 01, 2019, 08:16:14 AM
...

See next post.  I'm comforted to know I'm not the only one who is curious about those details.
Title: Re: Turret Crawl on USS Iowa
Post by: 230RN on August 01, 2019, 08:17:08 AM
Mike Irwin's and others' replies were very helpful, and many thanks. They're coming in too fast and I have to take some time to go over them, but thanks to all at this point.

("Incorrect. The primer was an actual cartridge such as the one that I showed in my previous post."  I think there was a little terminology mixup here between a "cartridge," meaning a blank cartridge, versus a bulleted cartridge.  For example, the starting "cartridges" for airplane engines and old-time farm tractors were blanks, but still called "cartridges.")
Title: Re: Turret Crawl on USS Iowa
Post by: brimic on August 01, 2019, 08:33:07 AM
"Just from what I can recall ready a Navy manual from the 1940s as a kid that belonged to my great uncle- the guns use an electrical fuse.
There is no cartridge- just various shells plus varying powder charges that get packed behind them."

Incorrect. The primer was an actual cartridge such as the one that I showed in my previous post.

There are some videos on Youtube that show Korean-war era Army heavy artillery, and one of the things shown is evidently the priming step. I came across it last night, but I'm having trouble finding it again.

Yes.
Title: Re: Turret Crawl on USS Iowa
Post by: K Frame on August 01, 2019, 08:56:41 AM
And here's a side view of the actual priming cartridge.

(https://www.practicalmachinist.com/vb/attachments/f24/134870d1427426830-ot-mystery-cartridge-id-m82-primer.jpg)

As far as I know, this has been the standard priming cartridge for heavy guns in the Navy and land forces since before WW II.


This is a pretty good photograph of the rear of the breech of a US WW II era 155mm "Long Tom" artillery rifle. You can see the recess where the primer cartridge goes and also the hammer mechanism that detonates the cap to ignite the primer cartridge.

(https://upload.wikimedia.org/wikipedia/commons/f/fb/M59A2_155mm_Cannon_Breech_20121013a.jpg)
Title: Re: Turret Crawl on USS Iowa
Post by: K Frame on August 01, 2019, 09:32:30 AM
"Like where in the turret do they even keep those priming cartridges... in someone's pocket?"

I'd suspect not. The priming cartridges are about the size of a .45-70 blank, and weigh about as much. I think the brass is a bit thicker, but similar. You'd not be able to fit too many of those in your pockets before the weight got to be a bit much.

That is an interesting question, though... How were the priming cartridges dispensed.

This is speculation, PURE speculation, is that the priming cartridges were generally kept in the powder magazine in packages and are delivered to the primer's position by hand, where they were placed in some sort of ready dispenser, possibly even a block like the old cartridge pouches with the wooden blocks that held individual cartridges.

Again, another pure guess, there would have been some sort of fire/flash proof cover or door over the primers to prevent them from detonating prematurely.


Again, just pure speculation.
Title: Re: Turret Crawl on USS Iowa
Post by: brimic on August 01, 2019, 09:37:40 AM
Quote
The priming cartridges are about the size of a .45-70 blank,
I immediately thought 45-70 when I saw the pic you posted in the post above. :P
Title: Re: Turret Crawl on USS Iowa
Post by: K Frame on August 01, 2019, 09:48:31 AM
Terry,

At 10:23 in the video that I initially linked you get a really good view of the breech of the gun.

If you look closely, you can see that there's an interrupted screw on the outside of the primer cartridge holder (also shown in the DeBange breech illustration).

That means to me that the cover for the primer cartridge holder is NOT in place and is NOT shown in that video. My guess? Possibly removed as part of the deactivation.


Here's a really neat illustration that I just found showing British sailors prepping the guns on the USS Rodney (the only British battlship, along with Nelson, to mount 16" guns).

In the lower right corner the guy is inserting the primer cartridge into the breech mechanism. Again, though, frustratingly vague as to the actual process...

(https://i.redd.it/twoi16hj3u011.jpg)
Title: Re: Turret Crawl on USS Iowa
Post by: Pb on August 01, 2019, 09:56:01 AM
"Just from what I can recall ready a Navy manual from the 1940s as a kid that belonged to my great uncle- the guns use an electrical fuse.
There is no cartridge- just various shells plus varying powder charges that get packed behind them."

Incorrect. The primer was an actual cartridge such as the one that I showed in my previous post.

There are some videos on Youtube that show Korean-war era Army heavy artillery, and one of the things shown is evidently the priming step. I came across it last night, but I'm having trouble finding it again.

Forgive the ignorant question-

So, do these guns use giant cartridges like field artillery, or loose powder, powder in bags or what?
Title: Re: Turret Crawl on USS Iowa
Post by: brimic on August 01, 2019, 10:15:07 AM
Forgive the ignorant question-

So, do these guns use giant cartridges like field artillery, or loose powder, powder in bags or what?

Bagged powder
Title: Re: Turret Crawl on USS Iowa
Post by: brimic on August 01, 2019, 10:15:49 AM
Terry,

At 10:23 in the video that I initially linked you get a really good view of the breech of the gun.

If you look closely, you can see that there's an interrupted screw on the outside of the primer cartridge holder (also shown in the DeBange breech illustration).

That means to me that the cover for the primer cartridge holder is NOT in place and is NOT shown in that video. My guess? Possibly removed as part of the deactivation.


Here's a really neat illustration that I just found showing British sailors prepping the guns on the USS Rodney (the only British battlship, along with Nelson, to mount 16" guns).

In the lower right corner the guy is inserting the primer cartridge into the breech mechanism. Again, though, frustratingly vague as to the actual process...

(https://i.redd.it/twoi16hj3u011.jpg)

The scale of those guns with people in the picture is really something...
Title: Re: Turret Crawl on USS Iowa
Post by: K Frame on August 01, 2019, 11:15:50 AM
"So, do these guns use giant cartridges like field artillery, or loose powder, powder in bags or what?"

Well, multi part answer.

First, there are three ways of doing it, and a lot of it depends on the bore size of the gun.

First, there is the fixed cartridge. Most land and naval guns used fixed cartridges (projectile affixed to the case that contains the powder charge) up to between 4 and 5". That's varied over time. For example, the American 5"/25 gun, developed near the end of WW I and entering service in the 1920s, used fixed ammunition, while the 5"/38 gun didn't.

Speaking of the 5"/25, here's an incredible photo of the mounts on the USS New Mexico. You can see the fixed rounds, nose down, in what I believe is the fuse setting mechanism.

(https://upload.wikimedia.org/wikipedia/commons/thumb/2/25/127mm_gun_battery_aboard_USS_New_Mexico_%28BB-40%29_off_Saipan_on_15_June_1944.jpg/800px-127mm_gun_battery_aboard_USS_New_Mexico_%28BB-40%29_off_Saipan_on_15_June_1944.jpg)

The British 4.5" quick fire dual purpose gun was about the largest gun of WW II that used fixed ammunition. It was chosen in part because it was about the largest fixed case round that would provide adequate performance and which could be easily handled by crew while providing a high rate of fire. Here's a British tar holding one...

(https://upload.wikimedia.org/wikipedia/commons/8/85/QF_4.5_inch_fixed_round_1942_AWM_137528.jpeg)

Next comes the semi-fixed in which the projectile is separate and the propellant is contained in a brass case. The US 5"/38 that was so heavily used during WW II as the primary armament on destroyers and AA cruisers and secondary armament on cruisers, modern (and some refitted older) battleships and carriers used semi-fixed ammo. Rate of fire was about as high as the British 4.5" but could be sustained longer because the crews didn't tire as quickly having to manhandle the whole shell.

Next are the component guns in which the projectile is separate, there isn't a case, and the propellant is in bags. With 1 exception, all navies and armies during WW II used this type of load with guns of about 6" or more.

I'm pretty sure that all US Navy cruisers mounting 6" (light cruiser) and 8" (heavy cruiser) guns used this type of round as did all battleships. The US Army's heavy artillery, 155mm and larger, also used component rounds.


The one exception to the heavy gun rule of thumb was Germany. They never adopted the interrupted screw (DeBange) breech, sticking with the sliding wedge breech system that Krupp developed in the 1870s.

Because of that, all German artillery, even the heaviest (the 15" guns on the Bismarck and Tirpitz as well as their super huge land artillery such as the 42 cm Gamma Morser siege howitzer, used a separate shell with the propellant contained in a brass case. The case was required to seal the breech.

In some cases, such as the 38 cm Seigfried K rail gun,  there were additional propellant bags loaded between the projectile and the brass case.

If you go here: http://www.kaisersbunker.com/cc/

You can see examples of various cases used by German guns during the WW I era with typical era headgear next to them for size comparison. Be sure to click on some of the larger ones. They're impressive.
Title: Re: Turret Crawl on USS Iowa
Post by: K Frame on August 01, 2019, 11:24:12 AM
"The scale of those guns with people in the picture is really something..."

Oddly enough Castle Key and I were talking about this very subject, including the size of the gun breeches, on my last visit down there last week. We were passing one of the Navy weapons stations around Yorktown and got onto a wide ranging discussion, and Dahlgren came up.

Dahlgren, in Maryland, was for many years the storage location for gun tubes. Some years ago they were doing an inventory with the intention of disposing of obsolete stuff (they still had several 18" tubes originally intended to go into the turrets on the Lexington class battle cruisers in the 1920s!) and came across two 14" tubes from the USS Pennsylvania, which had been mounted when the Pennsy was in dry dock at Pearl Harbor on December 7, 1941, but which had been removed and stored in 1945.

The Navy donated the tubes to the Pennsylvania Military Museum in Boalsburg where they are now an outdoor exhibit/memorial. Interesting photos of the process here: https://www.pamilmuseum.org/uss-pennsylvania
Title: Re: Turret Crawl on USS Iowa
Post by: K Frame on August 01, 2019, 11:35:35 AM
Speaking of the USS Pennsylvania, her bell is also at the museum in Boalsburg.

(https://www.republicanherald.com/polopoly_fs/1.672519!/fileImage/httpImage/image.jpg_gen/derivatives/landscape_700/image.jpg)

See that ragged chip in the lip right under 16?

I was there the day that happened.

I was working as an intern for the Pennsylvania State Museum & Historical Commission and one of the things we were doing was transferring artifacts from the main museum in Harrisburg to Boalsburg. A large exhibit of the USS Pennsylvania silver service had just ended, and the bell was going to its new permanent home.

A large group of museum staff drove up to Boalsburg with the bell loaded in the back of a panel van.

When we got there the riggers were getting ready to unload it. It was in its transport frame and on a very heavy pallet, but it needed to be slid to the back of the truck so the skid loader could lift the pallet out of the truck.

They rigged up some ropes to the pallet and the skid loader with the intent of easing the truck forward.

Everything was ready, the guy hopped into the truck, started it up and... floored the *expletive deleted*ing gas. Truck rockets forward, bell and pallet slides out and BONG! drops to the ground. The travel frame collapses, the pallet shatters, and the bell gets that nice big chip on the edge.

The ONLY saving grace of that entire mess is that he pulled forward so damned quickly that it was like a magician pulling the table cloth out from under the dishes. It happened so quickly that the bell didn't have time to tip over and land on its side -- it went straight down, and that's very likely why the bell's lip is only chipped and it didn't end up shattered into a dozen pieces.
Title: Re: Turret Crawl on USS Iowa
Post by: HankB on August 01, 2019, 01:22:47 PM
I found it interesting that the powder bags weighed 110 pounds each, and the video showed individual sailors simply picking them up from the transport elevator and carrying them over to the gun. Seems that could become tiring under those conditions during a long battle.
Title: Re: Turret Crawl on USS Iowa
Post by: K Frame on August 01, 2019, 02:07:01 PM
Oh yeah, definitely could be fatiguing, especially given how hot those spaces could get.
Title: Re: Turret Crawl on USS Iowa
Post by: K Frame on August 02, 2019, 11:09:04 AM
Hey Terry,

I think I have some more information for you, at least on the firing of British heavy guns. This is from the video I posted of the guy closing the breech on a WW I-era 15" naval gun... I've done a bit more research/reading, and I THINK I have the following information correct...

(https://armedpolitesociety.com/proxy.php?request=http%3A%2F%2Fpic80.picturetrail.com%2FVOL856%2F932748%2F20286314%2F414269920.jpg&hash=6b0a2c0ffac0f21081db1cf8e8d8fdb658a30e5e)

I've circled two areas in red.

The circle over the center of the breech shows the primer area. In this case, the full assembly is there and is closed as if the primer is in the mechanism and is ready to shoot.

You note the black cable going to the brass clip on the breech block . As the breech rotates counter clockwise, it meets up with another brass clip on the standing breech (the other red circle), which also has a cable going to it.

I'm about 95% sure that that is the electric firing interlock. When the breech is fully closed that interlock sends a signal back to the fire control center that the gun is ready to fire. When the gunner in the fire control center presses the firing trigger, an electrical current passes back down through the same cables to the primer cartridge and the gun fires.

If the breech block isn't fully closed the firing interlock circuit isn't complete and the gun can't fire.

After losing several battle cruisers during the battle of Jutland, in large part due to grave errors in the handling of the powder bags, including leaving the flash proof doors open, the British REALLY ramped up safety on their post war designs leading into WW II and created a whole series of electrical interlocks that would, were any of them not showing ready, prevent the gun from firing (others would prevent the power hoist from operating, etc.)

The system was complex, but it helped ensure that an accident in the turret couldn't flash down to the powder magazines.

The complexity of the interlocks (as well as other issues) were still being ironed out when the battleship Prince of Wales sortied out to meet the Bismarck and those issues cut PoW's effective rate of fire. Because the issues were ongoing the PoW's captain requested civilian technicians from the Elswick Ordnance Company, which developed and built both the gun and the mounts, to remain on board. I've read varying numbers, but apparently upwards 100 technicians were on board during the battle and actively participated in operations, helping keep PoWs guns firing until one of the quad-mount turrets jammed.
Title: Re: Turret Crawl on USS Iowa
Post by: 230RN on August 02, 2019, 11:47:41 AM
Mike, that was all fascinating.  The loading and closing of the priming breech is shown in your link,

https://youtu.be/lPEI6pQc4Sc

at 26:10ff, where they deal with firing "Atomic Annie" with a conventional shell.  I note the "triggerman's" lanyard is about 30 feet long. :)

Another interesting part of that video is around 3.42 where they deal with acoustic sensors to locate the position of enemy fire way back in Korea.  They refer to the "computers" in the sound van which do the calculation.  What is interesting to me is the current efforts of various police departments to use similar methods to locate gunfire in our cities.  There's a wee bit of phase detection and geometry involved in that.

A great big THANK YOU to Mike Irwin for providing the hard data regarding my dumb question about that priming cartridge/breeching.  Apparently, I'm not the only one who was curious about that.

And also, for providing so much "color" surrounding all types of artillery.

Outstanding !

Muchas Danke,

Terry, 230RN
Title: Re: Turret Crawl on USS Iowa
Post by: K Frame on August 02, 2019, 12:38:21 PM
Not really a dumb question at all. There's a lot about how they fire those big guns that just isn't available readily, but is sort of out there if you know where to dig and have the time to dig deeply.

I knew that the guns were electrically fired, and that they used a primer cartridge, but that was about it. Didn't know much at all about how it worked, didn't know that there was one guy whose job it was specifically to set the primer, etc.
Title: Re: Turret Crawl on USS Iowa
Post by: brimic on August 02, 2019, 12:59:59 PM
Quote
After losing several battle cruisers during the battle of Jutland, in large part due to grave errors in the handling of the powder bags, including leaving the flash proof doors open, the British REALLY ramped up safety on their post war designs leading into WW II and created a whole series of electrical interlocks that would, were any of them not showing ready, prevent the gun from firing (others would prevent the power hoist from operating, etc.)

The system was complex, but it helped ensure that an accident in the turret couldn't flash down to the powder magazines. The complexity of the interlocks (as well as other issues) were still being ironed out when the battleship Prince of Wales sortied out to meet the Bismarck and those issues cut PoW's effective rate of fire. Because the issues were ongoing the PoW's captain requested civilian technicians from the Elswick Ordnance Company, which developed and built both the gun and the mounts, to remain on board. I've read varying numbers, but apparently upwards 100 technicians were on board during the battle and actively participated in operations, helping keep PoWs guns firing until one of the quad-mount turrets jammed.

I saw a show about the USS Forestal just recently. The investigation showed that a few safety interlocks for arming missiles on planes were ignored+ old munitions of unknown cook off time + not enough trained firemen (who were pumping water on jet fuel fires instead of foam) is what killed over 100 men and almost sunk a carrier. Just a bunch of small overlooked/disabled things that stacked together to make a really huge accident.
Title: Re: Turret Crawl on USS Iowa
Post by: 230RN on August 02, 2019, 02:08:24 PM
Murphy has several advanced degrees in engineering from the Malevolent Institute of Technology.
Title: Re: Turret Crawl on USS Iowa
Post by: HeroHog on August 03, 2019, 04:40:28 AM
Some of them used Mercury "Triggers" to make sure the elevation angle was correct at firing. The Main "trigger" was energized and and when the ship rolled to the right angle, the Mercury completed the circuit and the primer was ignited. The Mercury was in a slight "U" shaped tube that had electrical contacts in it and was adjustable for the desired firing elevation.