Naval gun rifling cutter photo's

[Brians356]

I have read where the big naval guns use a progressive, or gain twist.

As shells got heavier, due to the shear inertia to start the shell twisting, the twist had to gradual.

Otherwise the torque could capsize the ship. Sooooo ...
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[Brians356]

Consider the analogous problems associated with precision turning and trepanning (hollowing) of the gigantic forged propulsion driveshafts in aircraft carriers. (The long trepanning lathe bed in the aerial photo. The cutting head advances 45 in/hr. Puget Sound Naval Shipyard 1958)





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[Brians356]

I'm not sure that cutting bit is as large as 16 inches, but there's no reference for scale.

This has about all I really need to know about naval guns:

Naval Gun Barrel Construction

a very complete manual of Naval Gun Barrels and interior balistics

www.eugeneleeslover.com

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[Dusty Stevens]

Watch how much bullseye powder they put in there

 

[Brians356]

Those powder bags used to be made of silk. Mind your fingers, lads! Yikes.
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[jelenko]

Watch how much bullseye powder they put in there

Looks like more than 110lbs. Each of those bags looks to be at least 30 lbs.

I read in a Wikipedia article that their dispersion was 220 yards - presumably at max effective range. At 20 miles, this would be .216 MOA.

 

[rayporter]

those 2 guys filming are the only ones on deck, i bet they thought the guns had muzzle brakes on.

 

[rayporter]

soooo, joe
how many grains can you pack into a grain or shall we call it a kernel?

did you ever weigh one?

 

[jelenko]

those 2 guys filming are the only ones on deck, i bet they thought the guns had muzzle brakes on.

Right. What is the overpressure? Gotta be non trivial.

 

[STS]

Those powder bags used to be made of silk. Mind your fingers, lads! Yikes.
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My mother sewed those powder bags together during WW2. She was pissed at the Japanese till she died at age 92.

 

[Brians356]

I think only a relatively narrow brass drive band incorporated into the body takes much engraving.

The article I linked to (previously) refers to copper driving bands, and copper fouling. It also mentions gain twist, but also tapered (ever widening) lands to maintain gas seal to the muzzle.
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[Brians356]

The way I understand it is the steel casing rides the lands. The band is there to engrave in the grooves and rotate the shell.

Added: so the band doesn't really support the weight of the shell. It's just there to turn it.

And for a gas seal, probably just as important as twist. The lands widen toward the muzzle to maintain gas seal.
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[joshb]

 

[jackieschmidt]

The bags are silk to avoid static electricity.
Also, I was under the impression that no one could be on deck in the vicinity of the big guns when fired due to the concussion.

 

[muleman69]

The bags are silk to avoid static electricity.
Also, I was under the impression that no one could be on deck in the vicinity of the big guns when fired due to the concussion.

I could not imagine anyone being on deck when they went off. I remember the 8" ones we had on tracks in Nam,huh,huh nothing wrong with my hearing honey....lol

 

[Dusty Stevens]

I could not imagine anyone being on deck when they went off. I remember the 8" ones we had on tracks in Nam,huh,huh nothing wrong with my hearing honey....lol

I seen somewhere that the ship moves sideways 7’ when they go off

 

[jackieschmidt]

I seen somewhere that the ship moves sideways 7’ when they go off

Dusty, it would seem so, but in truth, it does not. The ship weighs over 50,000 tons, the guns have a recoil system that absorbs the vast majority of the energy.
In theory, since there is always a reaction to an action, it possibly moves a non measurable amount.

Do Battleships move sideways when they fire? - NavWeaps

www.navweaps.com

 

[muleman69]

Dusty, it would seem so, but in truth, it does not. The ship weighs over 50,000 tons, the guns have a recoil system that absorbs the vast majority of the energy.
In theory, since there is always a reaction to an action, it possibly moves a non measurable amount.

Do Battleships move sideways when they fire? - NavWeaps

www.navweaps.com

Good read, can't believe the weight of those projectiles and what velocity. (16" Creedmores)

 

[sandwarrior]

Those powder bags used to be made of silk. Mind your fingers, lads! Yikes.
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Interesting factoid. The guy that invented the Momsen Lung for submarine rescue, also got the Navy to mandate that the bags the powder was stored in was AA cotton. Which doesn't give off static electricity like silk.

 

[sandwarrior]

Dusty, it would seem so, but in truth, it does not. The ship weighs over 50,000 tons, the guns have a recoil system that absorbs the vast majority of the energy.
In theory, since there is always a reaction to an action, it possibly moves a non measurable amount.

Do Battleships move sideways when they fire? - NavWeaps

www.navweaps.com

Reading the insert, I read that the battleship Missouri moves 6" sideways on a full broadside. That is a LOT of water moving sideways on the backside which in turn is going to create one hell of a trailing wake on the front side of the broadside. Somebody talks about ice. Ice is assuming the surface is frictionless. In a frictionless situation, the ship won't stop moving sideways. That is until something stops it. Water stops the ship.

The opinion created in the insert, and I'm not saying you are wrong jackieschmidt, say's to me that more mathematicians need to go out and get some REAL WORLD EXPERIENCE. I have seen dozens of pictures of Battleships doing a broadside to see a short trailing wake on the broadside. And most anyone who's been in a boat knows the difference between a wake and surface disturbance that the blast would create.

Again, think about 6" of water on the backside being moved by a 50,000 ton, 887'long, 30' deep surface. According to Bernouli, that would make a wave and leave a wake.