Greybeard
Member
It seem that lots of us are snowed/iced inside today with not a lot to do ... 
Battleships move sideways on broadsides?
- Thread starter ZekeLuvs1911
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Leatherneck, I had three interfaces with the NJ during those months.
1) Before missions, we'd be briefed where it was when it was in our AO.
2) The AF controllers would warn me about the areas it was operating in real time if they saw me heading toward them.
3) Listening to its guns firing and the shells exploding when it was working over the area near where we were based on the coast.
Never did have a good idea of how effective its Naval fire was, but it was a "neat" aspect of being there.
1) Before missions, we'd be briefed where it was when it was in our AO.
2) The AF controllers would warn me about the areas it was operating in real time if they saw me heading toward them.
3) Listening to its guns firing and the shells exploding when it was working over the area near where we were based on the coast.
Never did have a good idea of how effective its Naval fire was, but it was a "neat" aspect of being there.
braindead0
Member
Forget about it, Zeno already proved that motion is impossible anyway
Tamara
Senior Member
bountyhunter
member
"The big problem is persuading folks that "little motion" isn't the same as "no motion"."
EXACTLY: I remember taking part in the thread at the 1911 forum where the starter asked: When the battleships fire their guns, do they move in the water: The answer I gave (which is correct) is absolutely YES.
The eventual outcome of the thread was that I was branded a moron and subjected to a littany of ridicule. One noteworthy imbecile told me that I didn't understand that the recoil absorbers convert the recoil energy to heat so it has no effect on the ship. In fact, if the recoil absorbers are bolted to the ship, they are part of it. The assembly still has to "push back" against the recoil force of the gun. Since they are connected to the ship, the energy is still applied to it.
The truth is, the ship absolutely must move in response to the gun firing as required by Newton's law: for every action there must be a reaction. It is entirely possible that because of the ship's enormous mass, the movement of the ship is small enough that people on board don't notice it. However, sensitive instruments like the ones used to detect earth movement would see it easily.
Another point is what type of movement? If the "line of force" of the guns recoil (as determined by where it is pointed) is above the center of mass of the ship, it generates both a lateral acceleration as well as a rotational torque. What provides the "resistance force" against these forces? The water. Put your hand in water without moving and you feel nothing (forces equal on all surfaces). Move your hand through the water and you feel it "pushing" on your hand as the water tries to remain at rest. The enormous surface of the ships hull means it doe not have to move much to generate the required resistance force to balance out the recoil from the gun.... but it does have to move.
EXACTLY: I remember taking part in the thread at the 1911 forum where the starter asked: When the battleships fire their guns, do they move in the water: The answer I gave (which is correct) is absolutely YES.
The eventual outcome of the thread was that I was branded a moron and subjected to a littany of ridicule. One noteworthy imbecile told me that I didn't understand that the recoil absorbers convert the recoil energy to heat so it has no effect on the ship. In fact, if the recoil absorbers are bolted to the ship, they are part of it. The assembly still has to "push back" against the recoil force of the gun. Since they are connected to the ship, the energy is still applied to it.
The truth is, the ship absolutely must move in response to the gun firing as required by Newton's law: for every action there must be a reaction. It is entirely possible that because of the ship's enormous mass, the movement of the ship is small enough that people on board don't notice it. However, sensitive instruments like the ones used to detect earth movement would see it easily.
Another point is what type of movement? If the "line of force" of the guns recoil (as determined by where it is pointed) is above the center of mass of the ship, it generates both a lateral acceleration as well as a rotational torque. What provides the "resistance force" against these forces? The water. Put your hand in water without moving and you feel nothing (forces equal on all surfaces). Move your hand through the water and you feel it "pushing" on your hand as the water tries to remain at rest. The enormous surface of the ships hull means it doe not have to move much to generate the required resistance force to balance out the recoil from the gun.... but it does have to move.
Ebbtide
Member
Bountyhunter,
I read all that mess on the 1911forum. I don't think you are a moron.
However, if I bolt 10/22 to the side of the battleship and fire it, should the battleship move according to newton's law. Is it not possible that the ship absorbs all of the recoil, and therefore does not move (changes it position on the earth) at all?
Just wondering and trying to make all this math stuff make sence.
I read all that mess on the 1911forum. I don't think you are a moron.
However, if I bolt 10/22 to the side of the battleship and fire it, should the battleship move according to newton's law. Is it not possible that the ship absorbs all of the recoil, and therefore does not move (changes it position on the earth) at all?
Just wondering and trying to make all this math stuff make sence.
You are correct that some movement has to occur but it would be on the magnitude of a pissant vs a boxcar when you compare the projo and ejecta with the mass of a USS NJ. 
it is so little it is virtually nil. Not only that, but a ship is continuously moving because the sea is continuously moving. If the movements are synched just right they may cancel each other out. You are perhaps assuming the ship is in a vacuum sealed chamber with no forces working on it except the recoil?
it is so little it is virtually nil. Not only that, but a ship is continuously moving because the sea is continuously moving. If the movements are synched just right they may cancel each other out. You are perhaps assuming the ship is in a vacuum sealed chamber with no forces working on it except the recoil? gun-fucious
Member
being one inclined towards the duct tape and string system of proof
it would seem a military GPS on the ship might tell you if you moved
it would seem a military GPS on the ship might tell you if you moved
Thumper
Member
WOW.
Deja vu all over again.
http://www.thefiringline.com/forums/showthread.php?s=&threadid=102622&highlight=battleships+sideways
Deja vu all over again.
http://www.thefiringline.com/forums/showthread.php?s=&threadid=102622&highlight=battleships+sideways
Robby from Long Island
Member
It seems to me I read somewhere that at a range of 20 miles they could put a 16" shell within 100 yards of their target.
Now that's shooting.
Now that's shooting.
bountyhunter
member
"You are correct that some movement has to occur but it would be on the magnitude of a pissant vs a boxcar when you compare the projo and ejecta with the mass of a USS NJ. it is so little it is virtually nil. Not only that, but a ship is continuously moving because the sea is continuously moving. If the movements are synched just right they may cancel each other out. You are perhaps assuming the ship is in a vacuum sealed chamber with no forces working on it except the recoil? "
No, I'm just not in favor of teaching bad physics or things that are not true. It is a fact the forces in the example are tiny, but sometimes tiny forces are important. In fact, they built the universe we live in. The stars where the elements which make us up were born condensed from scattered clouds of hydrogen molecules whose garvity acting on each other drew them slowly together over billions of years.
It's important to understand a principle: that any force has an equal (and opposite) reactive force. It may be silly to think that firing a pistol affects the speed the earth rotates, but it does. We just can't measure it.
No, I'm just not in favor of teaching bad physics or things that are not true. It is a fact the forces in the example are tiny, but sometimes tiny forces are important. In fact, they built the universe we live in. The stars where the elements which make us up were born condensed from scattered clouds of hydrogen molecules whose garvity acting on each other drew them slowly together over billions of years.
It's important to understand a principle: that any force has an equal (and opposite) reactive force. It may be silly to think that firing a pistol affects the speed the earth rotates, but it does. We just can't measure it.
Zander
member
I suppose that would be so if you don't care where those 2700 lb. shells are going to land when you fire the next string.
We're talking about 787 million foot-lbs. of energy from one broadside. Seem impossible?
Per shell...
(2500x2500/7000) / 64.32 x (2700x7000) = 262,360,075 fpe
If you doubt the formula, here's a more believable example:
For Cor-Bon's lightest .40Auto load...
(1300x1300/7000) / 64.32 x (135) = 506 fpe
Would hundreds of millions of pounds of muzzle energy affect a battleship of 58,000 tons of displacement? Of course it would...enough so that, as mentioned before, the fire-control computers would have to take it into account.
Well, the simple answer is 'yes', but how about a more realistic example?
Have a man sit in a canoe [combined weight of 250 lbs., let's say] floating on a pond and fire a .44Mag carbine broadside three times as quickly as he can. Will the canoe move sideways?
Tamara
Senior Member
787,000,000 ft/lbs, acting on more than 100,000,000 lbs of ship, dissipated through recoil buffers, firing at an angle, and having its horizontal motion slowed by trying to force a 24,000+ sq/ft steel wall through water.
Your argument is convincing, Zander, but the arguments of, you know, actual battleship captains and gunnery officers is even more convincing yet.
Your argument is convincing, Zander, but the arguments of, you know, actual battleship captains and gunnery officers is even more convincing yet.
Zander
member
HEY!
You guys have been cheating...you're just pulling stuff from a previous thread on TFL. C'mon!
At any rate, there's no arguing with the numbers or the physics; Take my man/canoe/pond/carbine example and let's be a little more precise by scaling down the weight and reaction to FPE (ME) in our battleship example.
If the assumption is 58,000 tons at a displacement weight of 2,240 lbs./ton, we're looking at an FPE:weight ratio of a little more than 6:1.
Let's change the weight of the canoe and passenger to the weight of a rowboat [deeper draft] and three people instead of one. How 'bout a total weight of 1,000 pounds?
Using our ratio, let's have a Barrett 82A1 .50BMG semi-auto mounted to the center seat of said rowboat. We'll remove the muzzle brake and adjust the load/velocity of the Barrett to yield a ME of 6,000 ft.lbs. or so. With me?
Now, have one of the three on-board row the boat across the pond [or, what the heck, fire up a 5-horsepower Evinrude] until a decent velocity is attained and have someone else trigger the Barrett, pointed starboard at 90º to the rowboat's heading, at an elevation of...oh, 30º or thereabouts.
Is there any movement to port? Will the occupants notice that the Barrett has been fired?
You guys have been cheating...you're just pulling stuff from a previous thread on TFL.
C'mon! Well, now that I have had the chance to review the TFL thread, I'd say that there was no clear consensus.
At any rate, there's no arguing with the numbers or the physics; Take my man/canoe/pond/carbine example and let's be a little more precise by scaling down the weight and reaction to FPE (ME) in our battleship example.
If the assumption is 58,000 tons at a displacement weight of 2,240 lbs./ton, we're looking at an FPE:weight ratio of a little more than 6:1.
Let's change the weight of the canoe and passenger to the weight of a rowboat [deeper draft] and three people instead of one. How 'bout a total weight of 1,000 pounds?
Using our ratio, let's have a Barrett 82A1 .50BMG semi-auto mounted to the center seat of said rowboat. We'll remove the muzzle brake and adjust the load/velocity of the Barrett to yield a ME of 6,000 ft.lbs. or so. With me?
Now, have one of the three on-board row the boat across the pond [or, what the heck, fire up a 5-horsepower Evinrude] until a decent velocity is attained and have someone else trigger the Barrett, pointed starboard at 90º to the rowboat's heading, at an elevation of...oh, 30º or thereabouts.
Is there any movement to port? Will the occupants notice that the Barrett has been fired?
Tamara
Senior Member
Zander,
Some physicist will be along shortly, no doubt, to tell us that your experiment is off due to some problems with linear scaling of the forces involved.
Nevertheless, I'm game to try. Especially if beer is somehow involved.
"Hey, y'all! Watch this!"
Some physicist will be along shortly, no doubt, to tell us that your experiment is off due to some problems with linear scaling of the forces involved.
Nevertheless, I'm game to try. Especially if beer is somehow involved.
"Hey, y'all! Watch this!"
Zander
member
Ah...then the laws of physics aren't really immutable?
As long as all participants are really good swimmers.
LOL! If only you had a sense of humor...
Tamara
Senior Member
Hey, I'm not kidding...
There's a lake in my front yard, a johnboat in the shed, a boat ramp fifty yards down the road, and beer in the fridge; I'm pretty sure I can scare up the extra passenger (lendringser's usually up for loony stunts in the name of science).
You gotta bring the Barrett, though...
There's a lake in my front yard, a johnboat in the shed, a boat ramp fifty yards down the road, and beer in the fridge; I'm pretty sure I can scare up the extra passenger (lendringser's usually up for loony stunts in the name of science).
You gotta bring the Barrett, though...
Tamara
Senior Member
Drjones,
I live in Tennessee, you live in California; you're just gonna have to trust me on this 'un, h'mkay?
I live in Tennessee, you live in California; you're just gonna have to trust me on this 'un, h'mkay?
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