Can somebody explain what "flash" is?

[DeepSix]

Well, actually, I know that flash is a specific type of fire, but I was wondering if somebody out there who's familiar with surface ship gunnery could break it down for me and explain to me in layman's terms how the phenomenon works?

Thanks in advance!

[lesrae]

Not quite sure what you mean mate, what's the context? The only flash fire I know of is the liquid/gas/dust type, not any sort of artillery/gunnery fire.

[DeepSix]

Sure; I should have been more clear. The context in which I'm reading about it is Jutland. I'm reading Keegan's Price of Admiralty and he assumes a certain knowledge of terminology on the part of the reader. Part of his contention is that the British ships were more susceptible to flash. For example:

...British crews, in their determination to achieve the highest possible rates of fire in gunnery competitions, had removed anti-flash devices from the magazine trunks without realising that cordite flash in the turret labyrinth was the gravest danger to which battle exposed dreadnoughts.

He also mentions that victims of the flash that occurred on H.M.S. Lion were not burned. Clearly a battleship turret/magazine complex would be extremely vulnerable to fire, and if the protective doors to the magazines are open or missing, fire can reach the magazine and obliterate the ship; what I'm curious to know is how flash is different from a "normal" fire. Is it more lethal, perhaps, because it occurrs in a sealed environment? What are the things that trigger it? How does a battleship's turret help it spread? That sort of thing.

[Oberon]

I would have thought that a flash fire is a fire that suddenly occurs within a concealed environment...like perhaps a galley fire, or fire caused by an exploding shell within the turret. I think the whole 'flash' part of it refers to the speed in which it appears and gathers strength, like flash floods.

[TteFAboB]

Here it is:



Of course victims aren't burned, it is completely harmless, though it could lead to temporary blindness.

The trigger is the desire for information, curiosity. A photographer will ask to take pictures of a ship's turret, and if he reaches the magazine, he might accidentaly ignite the gun powder when discarding the flash bulb (I suppose we're talking about the old-school flash, which generated dangerous sparks and heat), and the photographer's clothes will start burning on fire, then all the photographer has to do is run in panic through-out the turret and the rest of the ship and there you have it.

[DeepSix]

Originally Posted by Oberon

I would have thought that a flash fire is a fire that suddenly occurs within a concealed environment...like perhaps a galley fire, or fire caused by an exploding shell within the turret. I think the whole 'flash' part of it refers to the speed in which it appears and gathers strength, like flash floods.

Thanks, Oberon, that's what I suspect; I'm hoping that somebody can either confirm or correct it and perhaps tell me some more details about it.

[Subnuts]

According to Castles of Steel, British warships during WWI had the anti-flash scuttles removed from their ammunition hoists to speed up the reloading of the big guns. Unfortunately, this meant that if an armor-piercing shell penetrated a turret, the heat flash from the exploding shell might start a fire in the powder magazine with predictable results.

[DeepSix]

Oooh, so it was the heat that touched off the fires, then.:hmm: That makes sense.... Tell me more!

[Subnuts]

Originally Posted by DeepSix

Oooh, so it was the heat that touched off the fires, then.:hmm: That makes sense.... Tell me more!

I'll quote from Page 667 of Castles of Steel:

Not all - or even most - of the blame for British losses at Jutland should be placed on thinner armor. There is no evidence that Indefatigable, Queen Mary, and Invincible blew up because German 11-inch or 12-inch shells penetrated their armored hulls and burst inside their magazines. Rather, the almost certain cause of these cataclysmic explosions was that the turret systems of British battle cruisers lacked adequate flashtight arrangements and that, in each of these ships, a shell bursting inside the upper turret had ignited powder waiting to be loaded into the guns, sending a bolt of flame flashing unimpeded down the sixty-foot hoist into the powder magazines. Assuming this to be true, blame lay not with the design of the British ships but with the deliberate decision by captains and gunnery officers to discard the flashproof scuttles originally built into the British dreadnoughts. The Royal Navy made a cult of gunnery. To win peacetime gunnery competitions, gun crews were encouraged to fire as rapidly as possible. Quick loading and firing required a constant supply of ammunition at the breech of the gun, and thus a continuous flow of powder bags moving out of the magazines and up the hoists to the guns. Safety became secondary; gunnery officers began leaving magazine doors and scuttles open to facilitate movement; eventually, in some ships, these cumbersome barriers were removed. But for this weakness none of the three battle cruisers might have been lost.

On the other hand, the battlecruiser Seydlitz at the battle of Dogger Bank took a hit in her aftermost turret, which caused powder in the turret to ignite, which started a catastrophic fire that killed everyone in the two after turrets. The ship survived after the powder magazines were flooded, and after that accident, the Germans started putting anti-flash scuttles on all their ships.

[DeepSix]

Originally Posted by Subnuts

Thank you very much; so it does indeed seem to be "flash fire" is loosely like "flash flood" - also interesting about the emphasis on gunnery competition; something the U.S. Navy overemphasized also.

[Subnuts]

Thank you very much; so it does indeed seem to be "flash fire" is loosely like "flash flood" - also interesting about the emphasis on gunnery competition; something the U.S. Navy overemphasized also.

Ever see that film taken during the 1950s of houses being destroyed in nuclear tests? If you look closely you'll notice the paint on the houses igniting seconds before the blast wave destroys them. I think that's what they mean by flash. Basically, a sudden intense pulse of heat. When the shell explodes, the sudden heat pulse would ignite everything flammable in the turret, including the powder.

[lesrae]

I was looking around for a technical description on the anti-flash system and came across this loosely related article on the USS Iowa: http://www.combie.net/webharbor/museum/bb61-2.html

[DeepSix]

Great find! I had forgotten about the accident on Iowa and never have seen the explanation for it. I think it must be a situation similar to flash - although slightly different since the article refers to it as a "cold barrel" explosion.

I've got to read it again and see if I can piece together how overramming the charge (which would mean improper seating of the bag) would ignite a turret fire.

Thanks!

[donut]

Overramming the charge,ignited powder bags with friction,& heat of compression.Reff:A.I.DuPont Comp.

[DeepSix]

Aha, gotcha. And the fact that the breech was still open allowed an ample supply of oxygen to reach the ignition?