How Do Small Waves Capsize Ships?
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- Опубліковано 27 тра 2024
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✩ABOUT THIS VIDEO✩
In this video, we investigate how Parametric and Synchronous Rolling means that small waves can easily capsize massive ships. We look at the causes, and the action that you need to take to counter it.
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No thanks, I already get my data stolen for free
30 minutes ago
The surfshark ad is... aggressively misleading. Your ISP and whatnot cannot see the content of traffic as long as the website is using HTTPS, which is almost every website in existence that people use. Your traffic is already encrypted. The only thing your ISP can see is DNS requests (i.e what website you're on, but NOT what you are doing *on* that website). Using a VPN service just changes who can see your dns requests from your ISP to the VPN provider. Tom Scott has an excellent video on the topic if anyone wants to learn more!
Everybody needs a slimy VPN salespitch in the middle of a short video...
VPN's are LEGALLY REQUIRED to store logs, EVERY SINGLE QUERY IS BEING STORED.
If you want privacy, self-host instead.
The physics that vessels deal with every day is fascinating
FALSE - Dwight Schrute
And make them uniquely dangerous. I love boats, I've only owned very small ones, with sails or oars.
@@capt.bart.roberts4975so a _small_ trireme?😊
I'm a pilot and the similarities in physics between boats and planes is so very fascinating.
@@wormyboot as an avgeek, I agree! Furthermore, there are some great similarities between aviation and F1 in terms of physics
I am about to graduate for my degree in Naval Architecture and Marine Engineering this year.
I now finally understand how parametric rolling work, and I was having a hard time understanding about it since I could not fully visualize how it works until I started watching this video. Thank you
Edit: I just graduated a week ago
3 weeks late but congratulations :)
Poggers. 👏👏
Congratulations mate
In one word: resonance. Which is almost always the answer in physics when the question is _"why does small thing make big thing happen?"_
Yup.
And we always have Unintended Consequences with our Resonance Cascade.
To be fair, very often the answer is also time.
Seeing even concrete buildings in sandy areas being ground through in relatively short amount of time due to sand particles being blown up for example.
My takeaway from Casual Navigations videos are it's best to just stay away from both ships and water.
Unfortunately, that doesn't work if you have to get stuff over water and it's too big to put on a plane (or would cost too much even if you could).
I agree
You can deep dive pretty much every mode of transportation and would have many risks, even when you're just walking. Best bet to stay safe is lying on your bed and don't ever move.
@@bltzcstrnx Bed sores . . . .
@@bltzcstrnx Unfortunately, there's a problem with that
I just took a final exam about a week ago involving periodic exitation and resulting oscillations of physical systems, it was interesting to learn about this particular real world case.
Great vid. Reminds me of running survey lines off Senegal.
6 weeks of 5m waves on the beam. As the height and period varied slightly the ship would move between comfortably rising up and down to rolling terribly.
We realised it was some sort of resonance and could be so bad that hull mounted survey equipment couldn't be used.
I've noticed this on a small scale before just on the lakes. We were usually tooling around in a small fishing canoe and when you get hit with a lot of small wake, you actually splash around a lot more than larger wakes from bigger boats. You can see it on the shoreline too, same effect. Large wakes just wash up and clap gently on the shore, but smaller wakes will splash very violently against anything fallen in the water close to shore, or any little eroded cubbies below the shoreline. Always makes a fun little clap sound lol.
Yay, back to the old format, thank you! Short but sweet
Nice video! The funny thing is, I am watching this right after passing an exam for Dynamic Response of vessels, second last before I get my Naval Engineering degree. Feels good man
I could listen to this guy talking about anything for hours and hours
I don't care what anyone else thinks. I really like the little ship animations in this video. Also, the information is presented in a way even I can understand...
I don't see anyone complaining about the graphics which I think are excellent.
You answer all the questions that used to flood my brains touring the rocks with my uncle, and his old bosun. The size of the shops was astounding, at the age of five. Uncle Arthur was in The Wavy Navy (Royal Naval Volunteer Reserve) pre war. He ended up being made a Commodore, we went to his promotion beano, at The Queens House in Greenwich Park. Phil the Greek was there, they kept my gob a long way away from him!
Does this also apply to sailboats? I imagine it is quite unlikely to hit the resonating frequency with a sailboat as the wind also heels and also to some extend rolls the boat?
I know on small boats, at least, the wind has a much greater effect on the potential to roll than the waves. but it may be that the force of the wind may make an asymmetrical rolling rate, which would make it harder for the resonance to develop.
The same physics apply to all boats. The change in stability of a kayak is quite noticeable when the wave length is just right, and the waves are sufficiently large that it lifts the center out of the water.
With a sail boat though, you have the advantage of a huge sail, which dampens most roll oscillations quite effectively, so this shouldn't be an issue as long as the sails are up.
No, not really.
When the sails are full they have a massive stabilising effect on sailboats. This is why you typically try to keep a storm sail up even in extremely adverse weather.
Additionally, the keel weight of a sailboat has a self righting effect. A full keel can upright a sailboat that has completely capsized. Assuming you haven't filled your sails with water.
@@joestevenson5568you're not comprehending the physics at play here. The only thing that matters here is the wave frequency matching the natural role frequency. With canvas aloft you simply slow down that frequency. The exact same physics are in play in either scenario.
Would installing a tuned mass damper (like in skyscrapers) help to counteract the rolling motion?
It would help, but the weight added would be pretty impractical, it could help with passenger comfort, but it won't eliminate roll. To eliminate roll, the damper would be ridiculously heavy.
it could. however it will take up a lot of space cargo could go into.
@@sirBrouwer That's the solution, then: put the cargo on a swing!
For damping to be effective, the damping has to be at least on the same order of magnitude as the forcing. The periodic component of wind on a skyscraper is presumably small relative to the overall force, but the periodic component of waves on a hull is basically the entire force.
Maybe, but just deploying some tiny flaps to make the ship roll slower naturally also works perfectly, so why bother? You can't deploy flaps to increase the air resistance of a skyscraper like you can the water resistance of a ship
I have searched many times & read many articles to understand parametric rolling but never did. but today I did thanks to you.
Thank you for your content. It is extremely informative!
thank-you, you channel has been so interesting to me. I see ships in the bay outside on a regular basis & I wanted to know more about navigation/ships and stuff. You explain things so nicely that I understand most of it...I finally see why graphs were important to learn in math class!
@5:45- "Or they could deploy stabilizers"
Wow! I just learned something new with this video! I didn't even know big ships had stabilizing fins to help with anti-capsizing. Cool!
Used on cruise ships frequently to reduce rolling. People get sick easily
Fantastic explanation of complex physics! Thanks a lot for taking the time to make these videos and share them with us!
What a nice explaination @CasualNavigation ! I always find it difficult to explain this effect to my fellow officers. Hopefully they will know what to do now, so I can also sleep during their watches.
Awesome vid as always mate, and it feels much more natural with letting the animations and subject take the lead and not your face. It's a fine face but when learning about something like this the subject being taught should be the focus and interrupting the animations with shots of you (again, it is a fine face and it's nice to put a face to the voice) interrupts the flow, at least just for me, so take it with a grain of salt. And please know I say it with all kindness and intent of being constructively critical. Keep these vids coming. I had no idea I was so interested in this stuff!
Very interesting. It makes me wonder how many of those mysterious ship disappearances throughout history were caused by this. Maybe the Bermuda Triangle just has waves that tend to mimic these resonance frequencies.
That doesn't explain airplane issues there.
>Maybe the Bermuda Triangle just has waves that tend to mimic these resonance frequencies.
It's pretty much just because it ruins an INCREIDBLY helpful (if not critical in some cases) piece of navigation.
If your main means of determining which direction you're going starts spinning wildly, you may end up just going in circles or running aground on something and such. Same for planes, but running out of fuel instead
Been watching your videos for a while now. I have genuinely enjoyed them. All but this one has been one of the most fascinating you have had. Excellent job with your graphs and images to make this easy to visualize and understand!
I didn't understand a word of this but it left me with a greater sense of loathing for the sea than I already had.
taking the issue to the next step is considering what happens if the ship does NOT have proper stability to begin with, or slowly looses stability over time due to changes in loading possibly from slow flooding. IME as Commander of a Coast Guard Cutter this situation was one stressed during our stability refresher training in Prospective Commanding Officer School as a result of a 'mishap' with loss of life when a vessel under tow suddenly rolled over slowly and sank taking some folks with it. In very simple words if the ship's 'natural roll period' changes to very slow & deeper rolls it means 'something is changing' and one is best advised to find out WHAT. In this example the vessel had continued to flood slowly and the slow rolls were 'saying this' but the fact was missed. The incident was captured on VIDEO and after the fact analysis was pretty clear as to what happened. Later in my career I was involved with a similar situation where a vessel suddenly rolled over and sank in very calm waters. There was significant loss of life. The vessel had been intercepted with MANY economic migrants on board - dangerously over loaded - and the decision to off load the 'cargo' was made. During the 'offload' everyone was moved UP to the weather deck whereas most had been 'below'. This weight shift significantly changed the vessel's stability (questionable to begin with) and again VIDEO of the evolution showed how the roll had significantly SLOWED and DEEPEND until such time the vessel simple did a slow roll and 'dipped the gunnel' and sank much to the surprise of on scene folks at the time but is later analysis EASY to see .... SLOW rolls can be very deceiving ..... if the 'depth' of the roll is increasing one is advised to ask "why" .... when change happens very slowly it is easy to miss what's really a big change! Slow deep rolls don't FEEL like danger . . .
You are irreplaceable in making me realise just how deep seafaring skills are. I never understood that, I just automatically assumed that you hop on board and watch for the sails to carry you (I was more into sailing than any other propellant as a fan of pirates, never went to sea in my life tho). I never assumed there is so much to consider even when sailing smoothly, not to mention manouvering in ports, rivers and so on. You have to understand water physics near perfectly (as well as we as humankind know it) to be a captain I would assume.
Great video. In The Confusion a group tries to sink a ship by putting cargo on it with the same frequency as the waves at the harbour entrance.
I did the math, in the scene at 1:50 with the three ships at different speeds, our friends up too are doing ~370 knots. A solid clip I’d say.
The nuclear cargo ships of the future
Your channel is awesome! The graphics are amazing and I have learned so much watching your videos! Thank you for posting!
I have a neighbor that raises cattle and hays fields for the cattle.
We talked occasionally, and I quickly realized the many little things that can directly change his profit margins. For example, cows must be within 200 lbs of a target goal; if not, the price per pound goes down 20%. And yes, this is why they are all the same size when you go to the store to buy meat.
Anyways, in this story about waves, they are so minor but can be significant.
Your explanations are amazing
5:21 now I would say cheeking the sea(head sea at a partial degree from head on coruse) I find helps smoothen the ride, with minimal pitching or bucking(3+m) but a fallowing sea sucks unless your wide,
If your narrow, the swells can redirect your course and give you a free ride in the way you could not want, autopilot is good, but nothing beats r Al wh el time in a fallowing sea
Seems it ought to be possible to design hulls so that their rolling resonant period changes as the amplitude of the roll increases, so that if the hull started rolling do to a synchronous input, as it developed, it would quit being synchronous.
Do modern ships have some sort of automatic detection system to deploy these flaps or display some sort of warning? A computer could probably detect the synchronous roll starting significantly before a human could, altho maybe it's not enough of an issue to warrant a dedicated system like that?
1:57
Now this is normally true, but in my little 28' boat if I was stuck beam to the sea, and if I pinned it, the haul would suck down and giv me increased stability with increased speed
But only worked to a certain hight of a ays 1.5m is normally the max eye would try this in
This stuff is bloody amazing. Especially to an idiot such as I am. I find anything relating to oceans and ocean travel fascinating, but I know little and understand less.
How on EARTH did people figure this stuff out! Thank goodness there are people out there with proper brains.
So this is why it's so hard to stay on the boat when I can't see the water moving
Excellent video as always 👏
Amazing information, when ya said about i figured what will be the problem, but before did not even think about this!
Hoping someone would be able to answer, why wouldn't ships keep the stabilisers deployed all the time rather than only when absolutely necessary, is there a significant downside other than the added drag and wear?
I suspect you just answered your own question.
OK, quick question, how exactly should one deal with a ship that is naturally stern heavy? I.e. a ocean liner built on the hull of a cargo vessel, in which the boilers, sternward dining hall, and rear promenade seem to cause the ship to have a serious problem with stern heaviness. I’m asking, as I’ve built a Lego Ocean Liner on the unitary hull of the massive cargo ship that was included in the first ever Lego city harbor, set 7994. Sadly, she’s really stern heavy, and already sits low in the water, due to her 2,000+, soon to be 2,500+, piece count. Granted a lot of those upcoming pieces are small, but still.
Rockatoa, Brickticks out!
At the end, you gotta do one on the "Small" boats if the Atlantic fishing fleet of USA and eastern Canada
I could tell it would be harmonics and almost clicked away. Glad I stayed for the parametric part. That was unexpected, but makes sense
Don’t know how or why you came up on my recommended.. but patiently now I’m patiently waiting on an Oceangate video 😢
Thank you very much.
Great stuff as normal. Thankyou!
LOL - I experienced this in my sailboat anchored in a marina one night. It was a long and annoying night.
Kedge over the stern and heave her around 30°? (tough in a marina to be sure) but mollified things a little in a bay.
It seems as though ships should be designed so that the resonant frequency would vary with amplitude, so that waves matching the resonant frequency can initiate a roll but then will no longer match when the roll gets severe enough to pose a risk of causing the ship to capsize.
Resonant frequency is constant in a harmonic oscillator, where the restoring force is proportional to the displacement, but not if the relation isn't linear. Imagine a perfectly elastic billiard ball on a loose (and massless) spring, between two perfectly elastic bumpers. If you move it over to the wall and let go, the spring will make it keep rolling back and forth, with constant period as the amplitude decays. If you nudge the table in time with that period, the ball will resonate: its period will stay the same and its amplitude will increase until it hits the walls. But if you throw it at the walls a thousand times as fast as it moved in the first example, it will bounce back and forth between the bumpers as though the spring weren't there, with a period equal to the time it takes to make a round trip -- that is, its period is determined by its speed. The same effect happens, to a lesser degree, whenever the restoring force increases with the magnitude of oscillation.
4:30 There's probably a specific reason there are two radars/dishes (?) on the right side and one on the left. Anyone care to explain?
I've heard that on passenger ships and yachts, eg "vain" ships that care about their looks, only one casing houses an actual radar device, the others are for symmetry, or looking more expensive and better equipped, thereby safer. Speaking of safety, maybe some ships actually have radar redundancy built in, in case one fails. But that's speculation on my part.
The satellite antennas (the domes) are usually put wherever convenient. They usually try to get them as far outboard and up as practical to avoid the main mast blocking the signal.
The radars (bar shaped antenna) are usually close to the centerline and high up. Having them centered helps reduce small errors in getting positions and such. Two radars are REQUIRED but some ships carry a third in case one fails. Only having one radar could result in the ship not being able to leave port until it is fixed.
6:30 "modern ships are no less safe than their older counterparts" while showing a picture of the Titanic lol.
Hey casual navigation, wondering if your reference to the wavelengths and frequency of the ships rolling points with crest and peak could also be substituted with crest and trough
Glad to see you got the titanic right! One stack smoke free!
Wow thats fascinating. I had no idea. How common would you say this is? Or is it just one of those freak things like Rouge waves?
This is of course exactly the same principle as a pendulum or a park swing and principal of small pushes in time with the swing or the small pushes from the escarpment on the pendulum to keep it swinging
Im on a ship now! Im more scared- this ship rolled quite a lot one time
Can you do a Video discussing how ships handle very large seas? Eg do they ever go with the waves or always into the waves?
This is very interesting, I’ll probably never use this knowledge, but it’s interesting
You got the physics right about constructive interference, but I think the animations are wrong: Constructive interference always happens at 180 ° phase shift, i.e. when the ship is leaning furthest to one side, the wave crest will be exactly at that side. This way the force pushing back will be highest, putting maximum energy into the system.
Ah, stupid, now I got it wrong, too. Constructive interference of course happens best at 0 ° phase shift. But we're not talking about constructive interference here, but instead it's catastrophic resonance. And that happens at 180 ° phase shift. So the animation is still wrong, but unfortunately the physics isn't quite right, either. It is not constructive interference but catastrophic resonance.
Amazing!
Great Video. Does anyone know the song during the surfshark ad?
Ships have resonance frequencies. That’s cool
Are there examples of actual ships that have capsized in either scenario?
You never explained if small waves are worse than big waves, you just explained how small waves can be bad too
Interesting parallels with earthquake resilience in tall buildings. Are there any ships with active mass dampers, or systems that move cargo to change the resonant frequency?
I don't think stabilizers change the frequency of roll. They act more like dampers taking energy out of the roll causing the amplitude to decrease.
Is stuff like this part of why there’s specific shipping lanes or paths that are followed, or are those more informed by pure dollar efficiency?
Hmm, that part abt the shape of a bow and how ocean liners compare to ther ships had me thinking: how would a ship with a tumblehome hull react to these conditions?
I know you just recently moved to show your face in the last videos. I appreciate that, but actually prefer this classic kind of video. I like the animations. They support the explanation by constantly visualizing the topic. The camera has it's use cases for some segments and video types, but in the last videos it was actually too much for my taste. Animations as a default is fine.
parametric rolling has some similarities with steering wobble on motorbike
Question: “Can a ship stay float without docking in ports and fuel supplies for more than 30 days?”
I would hope a ship can stay afloat indefinitely. The crew might have an unpleasant experience without food and weather would become much more dangerous once the fuel runs out. But why would the vessel just sink?
SS Baychimo stayed afloat and abandoned for decades.
Cool but I really wanted to know how fast the countermeasures need to be taken. Also, examples of ships that sunk due to this phenomenon.
Wow, that s interesting, I didn't Knie about anything of this!
It's like when you're riding a motorcycle and it starts wobbling at speed and keeps getting worse until you speed up.
So, as someone who finds this interesting, yet doesn’t work on or around shipping, is this something that happens all the time, and pilots/captains are working to correct this? Or is it something that would occur rarely and then everyone needs to hit ‘action stations’ to correct it?
I really want to see that ship flip over! Thanks for the video.
Resonance Frequency brought down the Tacoma Narrows Bridge.
I read the title before watching and immediately thought it was frequency.
I didn't understand why small waves are now more dangerous than big ones, because all I understood from this video was: Resonance. Why can't big waves cause it? Why are small waves (small amplitude) better at this, are they more often in typical resonant frequencies?
Can you make a Video about the RCGS Resolute?
How to fix the problem: wide boat
Yikes. This issues feels like a math test with a timer that you can't prepare for.
No studio shots anymore? It was nice to see you for a few vids though. You have a great channel!
Well, this does mean modern ships require more education, which has a limited supply.
New fear unlocked.. 😮
Are there automated systems to measure and identify roll synchronization?
That kind of knowledge you learn just to say you know it
What about the Tootsie Roll?
Is there actual examples of this capsizing a decent sized vessel?
There's no mention of righting levers and GZ + GM etc.
Could the Waratah have had this problem?
Is it really important to know the difference? In both cases, a course change changes the frequency and solves your problem.
are there any videos of this happening? i wanna see this so bad fr
My god, isn’t there any safe direction? How could anyone dare setting their feet on a ship when this is reality?
Can’t you put the containers that can float easier at the bottom and put the ones that would sink faster on the top
Syncronos rolling is dangerous af, that, and parametric rolling, usualy ud deal with them by altering course
What about rushing the engine! Could end with engine stop.
how do hydraulic capstans work
Cool
It's nice that you don't have a real-world tragedy that illustrates this phenomenon.
THANK YOU for not distracting me by showing your face. Save that for live Question and Answer videos. Thank you!
Small waves have much larger 'curvatures...' that is why