How much windage at 20,000 yards?

TomD

TomD

e publius unum
I took this picture a few hours ago at Fort Pickens, on the Florida coast. This is a WWII era 6" shore battery called a shielded canon. Most of the batteries at the fort are behind masonry or concrete revetments. There are a number of batteries from different eras from the Civil War to WWII preserved there.

I wonder how many clicks of windage at 20,000 yards with a 30 mph crosswind?

3560244941_a0929c20a4_b.jpg
 
1/4 minute clicks would be about 4 feet per click at 20k yards (running the numbers in my head, not a calculator).
What size is the X-ring?
How high above ground level would you have to be to see the target at 12 mi?
I'd guess at least a 2 hour sight-in period.
 
What !
No sights ?
Have your spotter walk the rounds in then get outta dodge, the incoming is gonna be hell.

Chuck.
 
Google search for shore batterys of santa rosa island.

Interesting.

Chuck
 
Jay said:
What size is the X-ring?
Click to expand...

The X ring could potentially have been as large as many hundred feet long, steel armored and moving at 30 knots, though the most probable target would have been a U-Boat.

Lets see, 20,000 yards is 200 times 100 yards so a MOA would be 16 and change feet, so your off-the-top-of-your-head estimate of 4 feet for a 1/4 min click is about spot on.
 
chuck furniss said:
What !
No sights ?
Have your spotter walk the rounds in then get outta dodge, the incoming is gonna be hell.

Chuck.
Click to expand...

These guns were given bearing and elevation date from remote sites where the info could be found optically or, later in the war, from radar. There are two related observation sites with close to a three mile baseline, located east and west or this battery, where they would get a relative bearing on the target. Given that data, probably accurate to within a couple of arc seconds, triangulation would rapidly give firing data to the guns. Wouldn't need need sights on the guns for most work but I'll bet they had a backup sight system for a close direct fire situation.
 
Surprisingly, exterior ballistics of the big guns is not much different than that of a rifle and a 30mph cross wind would have a similar effect as the same wind on an average rifle bullet. 3000 fps is 3000 fps whether the bullet is 200grains or 200 pounds. And 1 MOA is still 1 MOA. You just need to think big.:cool:

Ray
 
Tom,
One of my old, dear departed, buds was in the Navy in the Pacific in WWII. He said that shooting the 5"38's was a lot of fun [ as long as you were not being shot back at ].
 
Back when I was an apprentice gun bunny there were firing tables for field artillery with corrections for rotation of the earth while the projectile was in the air, for deflection due to rifling twist, and other stuff I can't remember. Armed with the range and firing tables the fire direction center could call reasonably accurate fire onto a target. Fire enough projectiles and you might hit what you were shooting at. I'm sure these guys used the same sort of thing.

Or there's the old fire on long, one short, divide the difference and pray method, or bracketing.

Now they use computers though.
 
I think even WAY back they had some sort of mechanism to allow for the roll of the ship. At least on a land based gun you don't have to allow for that.
 
I think that the first real computers were developed for naval gunfire. Navy had a female Commodore who was some sort of computer whiz. Never met her, but i saw her once.
 
I just found out that there are only 4 shield guns left in the world. Here is a link to some info on the guns.
 
Larry Elliott said:
Back when I was an apprentice gun bunny there were firing tables for field artillery with corrections for rotation of the earth while the projectile was in the air, for deflection due to rifling twist, and other stuff I can't remember. Armed with the range and firing tables the fire direction center could call reasonably accurate fire onto a target. Fire enough projectiles and you might hit what you were shooting at. I'm sure these guys used the same sort of thing.

Or there's the old fire on long, one short, divide the difference and pray method, or bracketing.

Now they use computers though.
Click to expand...
__________________________________________________________________________________________________________________________________

In WW 2 my father worked on the computers that were used to create the firing tables for artillary and later for IBM. He passed on in 1953 but I remember him taking me to work with him around 1948 and saw one of these machines.
Thousands of vacum tubes floor to ceiling in a room about 10x20 feet.
Data was punched out on cards in another room. Today a pocket calculater has more computing power.
My later reserch showed that each big gun had its own fireing table unique to that piece. Because of heat buildup these machines could only run for very short periods.

Chuck
 
papapaul said:
I think that the first real computers were developed for naval gunfire. Navy had a female Commodore who was some sort of computer whiz. Never met her, but i saw her once.
Click to expand...

I belive her name was Grace Hooper.
Chuck
 
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Let me operate the canon...

:D
First I need a diopter...set correctly on the tube, no wiggle etc .:D Then I need a dozen of hearing protections.:D then I might need a bigger space/room...and a box of soft drink :eek: And I'd need to pee before ignite that superduperloudenboomerearsplitchzen...or maybe I even need a dozen layer of diaper!...:D:D:D

In that era, the operator should be a marksman, or must be a type of "shoot and shoot again" man....I doubt if one shot hit could be done "regularly"...? You know the distance, V/BC/SD/ES of the "bullit", angle/cos you have to adjust etc, but you don't/can't know the "average" wind velocity between the muzzle and target, still many "swirls" out there etc,...and no windflags! (LOL)
Phew...:D - but interesting.
seb.
 
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