My dad had a 38 foot sport fisherman boat when I was 10 years old. I remember sitting on the boat’s side deck and making it rock by pushing on the dock with my feet. It took a while… I would push every few seconds, and then the boat would eventually start rocking after a minute or two. I was always amazed that I could get a 14 ton yacht to rock simply pushing on it.
So today I got to thinking… could I get a really big boat to rock back-and-forth by simply pushing on it for a while? I understand it might take quite a bit of time, but could I, for example, get the Queen Mary to noticeably rock using my muscle power alone?
I believe this is a real story, it was reported as such with fairly reasonable support.
The Captain of the USS Enterprise CVN-65, ran her onto a sandbar. He decided similar to your example to get every spare man onto the flight deck and have them run back and forth to rock the boat of the sandbar.
The Crew of the Big “E” is around 5000 sailors. They mustered around 3000 for this exercise and tried it with no results. The Big “E” weighs around 93,500 tons. 3000 sailors weigh around 300 tons (3000*200 /2000).
I see no conceivable way, one person could ever have an effect on the Queen Mary*.
It’s all a question of torque–can you exert such a certain foot-pound force on the keel to rock it back and forth? Besides explosives onboard your vessel, you ain’t gonna move it much. Most “capital” ships have their machinery (boilers, engines, motors, etc) designed around the centerline to prevent such a torque on the keel. Cite?
IIRC, there’s historical evidence with the P-51 Mustang–the damned engine produced so much torque, they had to manufacture trims into the wings to counteract the propeller.
Tripler
“I wanna rock!” ROCK! Dah danna dah nah! Nah nannah nah nah . . .
Well, you can’t just run back and forth willy-nilly. Unless you time your runs to the frequency at which the ship would naturally rock, you’re just wasting energy.
I do not know the details, but that is exactly what they tried and it failed to help. Trying to get 3000 men to run side to side on the flight deck, does not seem to me, like it could make much of a difference.
I don’t have the details as I said, however, I meant they were not doing it “willy-nilly” and were trying to use the normal rocking speed of the Carrier. A carrier lists or rocks about 1° or less under normal conditions. I think this was the approximate speed they were trying to achieve.
It is far easier on a sail boat. When I ran onto a sandbar, we had two people get off the boat and we swung the boom out and had one person go out on the boom to use it as a large lever to rock the boat. A carrier obviously has no equivalent.
I was a Snipe, for the life of me, I don’t remember where the mainsail halyard was on the carrier. If we had one, it would have to be on the tower. I suspect we did not have one as it would be potential FOD.
The principle of adding energy in tune to the resonant frequency would certainly work on the Queen Mary–in a frictionless environment, if you had the patience. My from-the-hip guess is that the energy you would add in each jump would be completely eaten up by friction within the deck, water, and in the air so that you could never build any kinetic energy up.
If she’s aground she’s not floating, in which case whether the men couldn’t rock her because of considerations relevant to the OP or due to her being aground and therefore not free floating and rock-able is moot.
No, she weighs 81,961 tonnes, according to Wiki. She is of 81,237 gross tons, but that doesn’t have any direct relationship to what she weighs, as I’m sure you know.
As to the OP, I’m with CookingWithGas. Theoretically, you could make a whole continent rock if it were balanced on a frictionless pivot. However, in the real world there is going to be friction caused by having to displace water (outside and in) to move the vessel. That friction is going to damp whatever you do. So while the QM will alter trim and rock when a fly lands on the starboard side, that’s going to damp out PDQ. So I think the answer is going to be "yes, kinda, in theory, but don’t bother trying to measure it.
I assume that you’re referring to the 1983 incident in San Francisco Bay; Enterprise was at the end of an 8-month mission that had taken her 46,500 miles at sea, and she was less than one mile from her destination - - her home port of Alameda – when the sandbar attacked.
Nothing there about running back and forth: the implication in the article is that it was a static weight shift. So, no resonant frequency would be involved, and as Princhester points out, being aground is not the same as floating.
The idea of moving the crew from on side of a ship to the other is an onld one and was used to free ships that had grounded, but it was only limited in effectiveness.
For more stubborn groundings, an anchor would be transported out to some location and dragged until it held. Then the capstan, or winches would be used to pull against it and hopefully off the ledge.
The closest event I can recall where moving the crew around like this happened to HMS Bristol.
HMS Bristol was a type 82 destroyer and she had a combination of steam turbines and gas turbines. She had a major fire in the boiler room, this was so intense that it buckled the plates above the boiler room, even though these were uder several inches of seawater - this had been put down to reduce the chances of fire spreading by conduction.
Its normal practice in ships to keep the outer bulkehads around a fire zone constanly cooled with water and this is called ‘boundary cooling’.
The problem was that the hoses were left on, instead of being turned on and off as needed and this caused a build up of water inside Bristol above the waterline.
This weight slopped Bristol over to one side and there was a danger she would capsize.
The crew not directly involved in fire fighting were ordered on to the upper deck, partly so that if Bristol capsized they had a chance of escape, but mainly so they were placed to counter the direction that Bristol had lolled to one side.
I’m not saying it prevented HMS Bristol capsizing, I was not there and I can’t find a report online, and stories like this become exagerrated, but it certainly helped the situation remain under control.
I’m afraid I’m going to have to join the chorus saying that the Enterprise incident that What Exit? is talking about isn’t analogous.
I’ll also point out that human body weight can have an effect on the attitude of ships. Now, with a target*, the bouyancy and mass distribution all combine to create a tendency to return the vessel to vertical alignment, in the absence of any other competing conditions. When submerged, however, a submarine really lacks the same natural tendency to return to a vertical alignment. To counteract this submarine crews will pay a lot more attention to trim ballasting than surface ship will - that is they will transfer fluids between tanks within the hull to make sure that the boat remains on an even keel.
I can’t speak from direct experience, I’d never served on a sub, but because of my training I worked with a lot of bubbleheads. I’d heard more than one talking about having “trim parties,” where off duty crew would get together to run through the boat, for the express purpose of taking the boat off an even keel - simply because of the effect of concentrations of bodies in extreme positiongs inside the sub. (The way I’d heard the call, it would be something like: “Hey, so-and-so has the watch, now! Let’s fuck with him by having a trim party!”)
To get back to the OP - I think that, in an ideal situation, yes, a single person could set up a rocking motion on the QM. Given the length of the ship, just how far out of the water she is, and other real world considerations, I doubt that it would be possible to arrange things so that there would be no other forces acting on the ship but that of the OP’s efforts.
*According to sub crews ships that are supposed to stay on top of the water are targets.
The point of shifting the center of mass when slightly stuck, is to move the center of mass over deeper water in the hopes that it will float. You couldn’t use the muscle force of a human to ever move the Queen Mary. A human couldn’t energize a feed back loop to cause the rocking. The buoyancy, gravity,waves, and friction will stop your efforts from ever seceding. Ships are designed not to role. By keeping the center of mass well below the water line, the ships use the water buoyancy to resist leaning from side to side in waves. Correct design will dampen the side to side motion, way beyond what a human can do to rock the Queen Mary. Until you find Paul Bunyan, Pacos Bill, or my brother Sylveste from ireland, you can’t rock the Queen.
He was in charge of the Boot Camp in Great Lakes when I was in Boot Camp and by report, never got another command at sea. Effectively stalling his career.
Antonius Block, that is exactly the correct timing for the incident, I went to Great Lakes in January 1985. Reports are, he tried to use the crew to rock the boat off the sand bar. Your article may not have mentioned this or the story may have grown in the retelling.
Right. Even the weight of one person causes the ship to list toward the side that person is on. If you could just time your runs from side to side to correspond with the natural roll frequency you could get it going pretty good. Just like pumping up a swing.
Of course you probably would need to be the only person on board. Otherwise I think the movement of all those others would disturb the natural roll frequency enough to defeat your efforts. Also, it would seem that a choppy sea might interfere. If the system is pefectly linear supperposition would apply and your roll input would simply add to any roll from the sea. However I don’t think the system, essentially a pendulum, is that linear.
When the Ile de France on which I was going overseas made landfall in the Channel and started up the coast of England, a big crowd went to the rail to look. The ship took on a big list and it would appear that the inclinometer on the bridge got close to some limit. In any case we were told over the PA system to not gather at the rail like that.
