In terms of the laws of buoyancy, no. Until you hit the volume of the entire ocean, displacement will continue to operate the same.
There's definitely a point where the physics surrounding our current shipbuilding technology will fail. Bulk carriers already have a problem with breaking in half from the force of the waves if they're not taken care of properly. There's a point where something becomes so big that modern materials cannot handle the stresses imposed by moving through the sea.
>Bulk carriers already have a problem with breaking in half from the force of the waves if they're not taken care of properly
https://m.youtube.com/watch?v=3m5qxZm_JqM
Check out the novel Guards! Guards! by Terry Pratchett. Not only is that phrase from it, but the entire Discworld series is loaded with insightful commentary and humor.
It could suck up years of your life in a great way.
Here's a 3 minute video with Pratchett! https://www.youtube.com/watch?v=jDF4AHZFQdw
I like how million to one chances crop up several times in the Discworld series. With an acknowledgement by all involved that its a guarantee of success
Cello. As in cellophane.
Sellotape is a British brand of cello tape. Don't know whether it is sold in Australia.
In America, one typically calls it Scotch tape, even though that's also a brand name for 3M's version of cellophane j tape. The short form cello tattooed is not used in America.
Much safer.
I once convinced a friend that due to it's cheapness and durability duct tape is used to help heat shield spacecraft on re entry. I said it as a throwaway joke, didn't really think he'd believe me, but I must have been convincingly deadpan because the next day *his* best friend came and found me and relayed this amazing fact they'd just learned about spacecraft.
I was at a music college for rock and pop bands, there was a lot of Spinal Tap-esque characters. When I think about that incident charitably I tell myself that they were probably stoned.
several of those concrete ships became piers, I loved to visit the one in Santa Cruz, CA, I vaguely remember being able to go the whole length of the ship (Bow to Stern) I believe it finally broke up in around 2001
http://localsantacruz.com/history/history-seacliff-beach-cement-ship/
Funny story, when Japan released the (fake) public figures of the Mogami-class cruiser, the Director of Naval Intelligence reportedly said "they're either building their ships out of cardboard, or they're lying."
It turned out both were partially true in a sense; the Japanese had lied shamelessly about the true displacement, while the ships themselves were notorious for flexing and being too lightly built.
For those who don't know, Japan wasn't lying and saying the ships were bigger, but actually smaller than what they really were. This was in an attempt to skirt global naval treaty limits which limited the size and armaments of warships.
This vessel in particular was:
- built for river/lake transport, but operating on the black sea
- almost 50 years old
- inspected and found lacking and barely seaworthy 2 years earlier
7 crewmembers were killed.
I loved this but im so confused
I feel like it must be a skit , just the way they go back and forth, however, i feel like if it is a skit, its referring to something?
Please help
https://www.snopes.com/fact-check/the-front-fell-off/
> the parts of the politician and interviewer being played by Australian television comedy duo John Clarke and Brian Dawe as **they discuss an oil spill that occurred in 1991 when the Greek tanker Kirki lost its bow off the coast of Western Australia**.
tbh I had always thought that just the "front fell off" guy was an actor and the interviewer was a real interviewer who was taken hilariously out of context.
Those two were doing saterical interviews in that format for almost a decade before John Clarke passed away in 2017.
If you haven't already, search YouTube for "Clarke and Dawe", there's a huge collection of their old videos. Their commentary on Quantative Easing from the GFC is a particular hilight.
> Those two were doing saterical interviews in that format for almost a decade before John Clarke passed away in 2017.
_______
>as they discuss an oil spill that occurred in 1991
Sounds like quite a bit longer than "almost a decade"...
You're right. [According to wikipedia](https://en.wikipedia.org/wiki/Clarke_and_Dawe), what I meant to say was "for the better part of three decades"
> Clarke and Dawe (also stylized as Clarke & Dawe) is an Australian news satire television program that originally aired on the Nine Network from 1989 to 1996 and later on ABC TV from 2000 until 2017.
I can imagine this as a Monty Python sketch. I can’t decide who should play either of the two roles.
Chapman, Cleese, Idle, and Palin could have pulled off either role.
I can’t really see Terry Jones, though.
Waves would probably be less of a problem on a huge ship with significant draft. If the wave height is negligible compared to the draft and roughly the same volume stays submerged all the time, there won't be as much shear stress on the hull.
Of course if the size and draft are too big then the question is what you would actually use such a ship for, because you either have to design ports to accommodate that huge ship. Or just never dock anywhere at all.
it's not the wave height that's the issue, it's the wave length.
What makes the container ships break apart is from 'hogging' and 'sagging'. If wave tops are at the front and end of ship and the wave trough is in the middle, it causes ship to bend down/sag. Likewise if wave troughs are at port/stern of boat and wave peak is in the middle. It causes repeated stresses that eventually break the ship apart.
My cruiser steamed through a class 4 typhoon because the captain was an idiot. Most frightening night of any of our lives. Lost guns, antennas, hatches, the ship's bell. Pictures from the bridge of the bow just... gone; fully submerged. Their were definitely moments where the ship righting itself wasn't assured. The Captain got reamed by an admiral over the primary radio channel, which is completely unheard of.
Yes. In World War 2, Admiral Halsey sailed the Fifth Fleet into not one, but two Typhoons. Several destroyers were lost, because he had refused first to allow them to refuel early because he thought the Typhoon would pass by, and then when he realized too late that the storm was going to hit the fleet directly, the destroyers lacked the fuel to maneuver how they would need to in order to ride out the storm. At the same time, the fuel in destroyers of the day was ballast that gave the ships stability. Without that fuel, they were top heavy and prone to rolling over in heavy seas.
Several destroyers and hundreds of men died.
There was another even where a US Navy cruiser that had been damaged in battle foundered and sank on the way back to the US for repairs in a heavy storm. One of the risks that they had to take then was sailing all the way back to the US or Hawaii because there just wasn’t enough infrastructure in the South Pacific to repair battle damaged ship. Even Australia lacked the necessary shipyards to do more than temporary patching, which didn’t always hold up to rough seas.
Re: that first one, they also nearly lost a carrier and a certain officer named Gerald Ford in the process. That certainly wouldn't have had any major ramifications in politics later.
Or or or how about his one. You don't even have to open it just read the link.
https://www.businessinsider.com/how-george-hw-bush-avoided-being-eaten-by-cannibals-in-world-war-ii-2017-12
With modern weather forecasting, they simply avoid it.
Heck, they don't even like them in port for big storms.
Norfolk, VA it's a thing there when a hurricane is coming towards them to go watch the parade as every Navy ship that can put to sea puts to sea in order to get out of the way of hurricane -- and that's from Hampton Roads, one of the world's best protected harbors.
https://www.youtube.com/watch?v=CMlgNjqSHHo
A quick Google search found a Thai naval vessel that sank last year. It was 40+ years old. Cause was due to heavy weather, water entered the air intake for the power generation and shut down all the engines. Once those are gone, it is just a matter of time before a vessel sinks due to not being able to maneuver.
In the run up to WW2, Japan knew they were never going to win numerically, so decided to try and compete on quality of ships. At the same time, they tried to at least have the veneer of adhering to international naval treaties.
This led to ships that were very top heavy due to their heavy armament, and with hulls buult with new electric welding techniques to save weight.
During an exercise, their 4th fleet was caught in a typhoon. By the end, two destroyers had lost their bows entirely, nearly all destroyers suffered damage to their superstructure, two of their new heavy cruisers developed serious hull cracks, and two of their light carriers suffered damage to their flight decks.
Same, been in waves that were 30', but spaced really far apart. It just rocked us to sleep. But also in 15' waves across the beam and high winds, shook as all around and everyone was seasick.
If the draft depth is substantially deeper than the tallest wave, it won't matter (because even if there are two peaks at opposite ends of the ship, with a trough in the middle, a "peak" barely lifts with any force).
I mean, if you take that logic far enough, you begin to describe a submarine. So sure, but suffice it to say they have their own engineering challenges :D
My point was if the draft is significantly larger than the wave height then the effects you're describing become negligible. The hull will remain significantly underwater and will not experience much bending or sagging.
There's a funny thing about drag and the length of a ship, though. Generally the longer a ship is the faster it's able to move because of a reduction in drag. Look up "hull speed".
Ok, new plan, giant cargo carrier that uses normal cargo ships to ferry things into and out of ports. Impractical? Yes. And environmental catastrophe in the offing? Absolutely. But can one really put a price tag on having a ship so large that the far end is below the horizon?
Sounds good. But best I can do is [a shitty tunnel full of Teslas.](https://archive.curbed.com/2020/7/23/21334351/elon-musk-boring-company-las-vegas-tunnel)
Yours,
-Elon
Technically speaking, all the ships in the ocean cause the sea level to go up a tiny bit right? Or is it so negligible that it basically doesn't change?
Yes, and yes.
It's estimated that the global maritime fleet is roughly 2.2 billion tons, or 2,200,000,000 tons. The oceans of the world are roughly 1,450,000,000,000,000,000 tons. So, the mass of every ship in the world is roughly 0.000000015 percent of the mass of the ocean.
Using the above estimates, we divide 2.2 billion tons of ships by the density of water (15974.36 drams per cubic foot) to find that ships displace 405,098,901,000,000 teaspoons of water globally.
We then divide the volume of water displaced by 430,566,400,000,000 square yards (the surface area of the ocean).
As a final result, we get that the oceans are raised by precisely 0.000218356783 inches.
> Bulk carriers already have a problem with breaking in half from the force of the waves if they're not taken care of properly. There's a point where something becomes so big that modern materials cannot handle the stresses imposed by moving through the sea.
This isn’t really accurate. Large bulk carriers and tankers operate just fine. A tiny handful of failures have occurred that make the headlines but there is no generalised problem with stresses on very large cargo vessels. Further, the problems that have occurred have been due to design failures in the early days of building such large ships, and certain unwise cost savings made in construction.
We haven’t even begun to approach the maximum theoretical design strength of steel in shipbuilding design.
The reasons ships aren’t made bigger are economic and practical, not structural
The largest cruise ships are still only at about 362 meters, compared to the, by now, standard for megamax container vessels of 400 meters... So yes, they can get bigger, but you also need to make sure you have a business for that many people
Many places are starting to limit the size of calling cruise ships, ie the Galapagos only allow ships with 100 or less passengers if I remember correctly
For container vessels it would probably be something like the Suez canal that limits it, but I think the next advance in that field will be one or two more rows. Currently they are at 24 rows, dubbed megamax-24. I have heard a rumor that a gigamax-25 has been pre approved by a classification society. The largest cranes can theoretically take 27 rows
For tankers (and dry bulk) it would probably be the depth somewhere that limits them. But as the biggest usually are build for a very specific trade you can get around a lot of the most notorious limitations if you want ie Malaga Strait
It would for most not be the buoyancy that is the limit, but the stress factors (Share Force, Bending Moment and Torsion) and keeping a legal, positive GM (distance from center of Gravity to Metacenter height, a number for the ability to upright itself) for the cruiseship and the empty tankers
Hope this answered a few things
Source: second officer on a merchant vessel
It depends. If we are talking hypothetically, no, as you could hypothetically put a ship on a perfectly flat plane of water with no disturbances, and it would be fine.
In reality, things like waves, the load of the ship, moving the ship, and the structural materials the ship is made out of all limit the size.
Buoyancy doesn’t have a limit, all you really need is to displace water to force the ship to float.
And yet, the mega ships we're building today would've been thought impossible mere decades ago, but here we are.
If there's a limit, it'd be return on investment.
One major limitation is the dock facilities. Massive cruise ships require huge docks that can accommodate their length and draft, and it’ can be expensive and inconvenient to continue expanding existing docks.
Yeah. Eventually we won’t be able to produce a material which can handle any more stress, but at that point it would be better to just make more little ships, or make a “raft train.”
well, just adding a lot of steel frames and reinforcements where needed works, especially with the help of computers to simulate stresses.
Engines become more efficient the larger they get, and larger ships have relatively fewer crew. I'm sure there's a limit though, but theoretically, no.
the limit we had on size when I worked at Mærsk was the capacity of the docks to be able to load/unload from the ship. If the crane can't reach because the ship is to large on any given axis or if the draft is too deep? then you have a problem...
Yep.
And there will always be a few ports that are able to handle them, like Rotterdam for instance, we're among the first to have the new generation of cranes for the new mega carriers, and was one of the few ports in the world that could handle the vale super ore carriers.
But they're mega investments, hence the limit on ship sizes is a ROI one.
Also you must be a Dane, using the correct spelling of maersk, apart from having worked there of course.
Theoretical, the sphere of the earth would be your only real limiting factor, unless you made a ship that acounted for the curved shape of the earth, then your limiting factor would be the length of the sea.
or build lot of small ships, we'll call them 'rail cars', all connected end-to-end, being propelled by a large Engine car in the front, and a caboose in the back.
Sooner or later you're just going to be splitting hairs on the difference between "Really long ship that stretches from New York to Ireland" and "Really long pontoon bridge"
Not really. All of those factors get easier to design around the bigger you get. The biggest factor limiting ship size is harbor depth and dock size (as well as canal size depending on route). If the infrastructure and demand supported it, ships would be big enough to match.
Edit: I forgot shipyard/dry dock size as a limiting factor.
Boyancy isn't an issue as it is related to the "hollow" volume inside the ship and the Archimedes principle https://youtu.be/bKToF_t5LAU
The major issue as you get much larger is shearing stress on the metal frame where the hull could potentially fracture and let the water in.
I was thinking something similar - like a train of smaller hulls underneath, but on top was a large platform that supported the living/cargo section of the ship
Mostly just practical limits. *Seawise Giant* was too big to navigate the English Channel or the Suez or Panama Canals. There's just not many reasons to make a ship that big.
As many others pointed out "Sea Worthy" and "will it float" are not the same thing. Also at some point you start to strain the idea of calling it a ship.
The ocean is not flat, it moves around a lot. At some point you run into mechanical limits of a rigid structure, if you had a "ship" that was 10 miles long and the front end encountered a storm that blew it violently in one direction while the back end was still like an hour away, if your vessel as rigid or even semi-rigid, it would tear in half.
But if you don't limit yourself to what we normally think of as a "ship" you could, at least in theory, do all kinds of crazy large scale things. For example you could create a series of large floating "nodes" connected by flexible pathways and spooling/retracting cables that allow it to bend and move and change shape with the ocean conditions. If it could very very slowly move around the oceans using some combination of sails and motors, a kind of large floating migratory city, that could become enormous. But is that really a "ship" at that point? And of course even if you could do it, is it feasible?
If it were still long like a ship, I can't imagine it wouldn't coil up like a snake. Might have to be approximately circular, in which case it's really not going to want to move against currents and would probably wind up crashing on shore.
What a weird thought experiment.
ELI5 - MONEY, ECONOMICS, EFFICIENCY, INFRASTRUCTURE, STABULITY restrict how big they can get.
Not a naval architect but used to work in the merchant navy on container ships.
To my understanding, there's no real theoretical limit, they can keep getting bigger and bigger on paper. I worked on MV Erving, which was 366m long (~1200ft) and could hold 16000 containers.
Back when it was built it was about getting as much cargo from one place to another as fast as possible. It had a huge engine (2 stroke diesel that created 75000kw of power) cause back in those days that is what the goal was. Now it's all about economics and saving money. Most high streets still need the demand of things getting from one country to another as fast as possible, but it isn't money efficient and its better for shipping companies to take a little longer but in the meantime save on fuel. My ships was spending roughly $2.5m every 2 months to refuel.
Money aside, there are other major infrastructures to be majorly aware of, such as the Suez and Panama canal. They save the shipping companies a lot of time and therefore money on fuel, and allow shipping companies to make more money by being able to deliver their cargo and get new things in the shop a lot quicker than going round the capes of South America and South Africa. Ships are often restricted to the dimensions of these canals and ships are even named after this such as PANAMX containers, meaning the maximum size of a ship to fit through the Panama canal.
Another issue with making bigger ships that a lot of people aren't aware of is the depth of water around ports. The ship I worked on was so big that we were restricted into what ports we could enter due to fear of grounding so if ships were made bigger, they would have a greater draft and therefor would run higher risks.
While larger ships can potentially carry more cargo or passengers, there are limits to the efficiency gains. Beyond a certain size, the economies of scale may diminish, and other factors such as loading and unloading times, port infrastructure, and operational complexity may offset the benefits of increased size.
Lastly is overall stability, even the ship I was on, when it was fully loaded, and we had some bad weather, it would roll like crazy. Like most things made from metal, they are designed so that they bend and flex. I imagine there comes a limit to this, longer something is, the more it can bend/flex but yeah, within limits for it to still remain safe.
Unfortunately I don't know much about cruise ships, personally I think they are unnecessary and would advise people to read up on how much they pollute, but yeah hopefully that helps give a bit of insight for you!
The size of the biggest ships is usually limited by the route they are traveling. For example, if they have to fit the locks in the Panamacanal. These are called 'Panamax ships' and they are amongst the biggest they build.
Panamax are actually among the smaller classes of ships. Post-Panamax and Capemax ships that transit around the Horn/Cape of Good Hope instead of through one of the canals are much larger, and there's plenty of ships that just go between continents without needing to hit a canal and are larger than Panamax.
Adding to your post: This is exactly why ships are called stuff like panamax, suezmax, supramax and several more \*max.
They are made to fit within specific limiting parameters.
On the open sea, they are only limited by what can be safely built within a budget.
The limit would be the structural strength of the materials used to build the boat. (As well as the size limit for being able to fit in ports)
There is no "buoyancy" limit, being able to float simply depends on displacing enough water to match the weight of the boat.
To be useful in the Northern Hemisphere a ship needs to fit through the Panama Canal. Recently upgraded locks allow for ships up to 51.25m/168 feet wide and 366m/1201 feet long.
There is not really any limit to how big a ship can be. If there were a biggest ship hull that was possible you could just take two of these hulls and connect them together to make one twice as large. So there can not be a largest theoretical ship size.
In fact the current largest ship are kind of doing this. It have the hull of a super container ship but have two hulls connected together with big cranes mounted on top of it.
The only limit would be the physical resistance of materials. But if you manage to build something like a very large plate, for instance, with high borders, you can make it an insanely large ship. You merely have to get materials which will resist the huge torsion forces from having parts dangling, while other are pushed by waves, the parts in question changing with the underlying waves.
So, the current sizes are determined both by the sizes of the bodies of water / harbors (because, if you need 150m underwater and 800m abreast to be able to navigate, it *might* cause a few problems to reach a harbor, or to use channels, etc.), and by the economical use. If you plan to take 10k passengers, a ship maybe 20 or 30% larger than what we currently have will be enough. If you want to take 250k passengers, you'll build larger.
Same for cargo: If you need to take 100 times the number of "boxes" a very big container transport does today, then yep, maybe you'll build larger. But, then again, you'll need facilities which can accommodate such a giant ship. And unless several ports invest in order to be able to do so, you won't be able to use your ship, in practice. Considering the cost of a ship, you don't want to build a giant you cannot use.
So, the limits are more because of economical and practical constraints, than physical ones.
Us navy veteran here. I suspect the practical limiting factor would be not the ship itself but port facilities. Ships need to tie up pier side and on Occasion get serviced. If there is a big enough space that’s a problem.
Oh. Also insurance. Ships must have insurance. For a mega gigantic ship the insurance rates might be prohibitive.
For cargo ships, the practical limit is the size of the Panama and Suez canals. Ignoring those factors, you need to worry about waves and wind and the depth of the ocean where you want to make port. There's nothing about floating that gives us a limit though.
The biggest issue for ship size is where you put them. Shipping ports are constantly upgrading to allow larger and larger ship. But if there are currently no points that can handle your ship, you can't do anything with it.
Other considerations are ports large and deep enough. Height would be limited to any bridges it would need to navigate beneath - or canals it needs to traverse.
Couple of things… since I’ve been tangentially involved with several of Royal’s new builds…
If you’re talking about *Icon of the Seas*, they didn’t “just give the go-ahead”, that ship is less than 3 months from completion and will enter service in January. They take about 3 years to build following another 4-5 years to design and do the engineering on (which is why when they design one, they usually build at least 3 of them. Designing a ship is expensive af).
In terms of size, Icon Class is only a few feet longer than their existing Oasis Class ships, and a few feet narrower (called “beam”). In terms of overall size, it’s comparable to some of the very large container ships.
The only real constraints to size are needing a dry dock big enough to accommodate the construction (and later, repair and maintenance), and you have to be able to get it from the yard to the sea - Icon is being built at the Meyer yard in Turku, Finland, and getting from the Baltic to the ocean involves getting under a bridge on the west side of Denmark that has a maximum clearance (also called “air draft”) of 57m. Ships built in other yards don’t have that limitation.
The ships also have to be able to put into the various ports of call, where the channels need to be deep enough to accommodate the approximately 9 metres of ship that is below the water line (called “draft”) and be able to maneuver the ship in those conditions.
For some ships, they also have to be able to fit in the locks of the Panama Canal.
When you see a measurement like “Gross Tons”, that’s not a measure of weight, but rather one of *volume* (of the enclosed portions of the ship). This is more of an administrative metric that guides things like number of lifeboats, passenger capacity, minimum crew, taxation, and so forth.
The actual weight of a ship is considerably less since most of the enclosed space of the ship is just empty space filled with air. A surprising amount of that space is actually dedicated to air handling and ventilation throughout the ship.
A ship the size of Icon probably has an actual mass of a little over 100,000 tons.
Ships that size have been traversing the seas for years. [Ultra Large Crude Carriers](https://www.wikipedia.org/wiki/TI-class_supertanker) carry around 400,000 tons of oil and are around 1200 ft long. They are so large that they are effectively at sea their entire lives and can only moor to pipeline piers further out.
Main limits are port depths, dock sizes, and shipyard sizes. And at least with passenger/ cruise ships, they've mostly grown taller and wider over the years. Just compare Titanic to Queen Mary II. QMII is less than 200 feet longer than Titanic but about 1.5x as wide and 1.5x as tall (from the keel to the top deck not counting the funnels) iirc. Cruise ships are even bigger than QMII because they're leisurely cruising around calm(ish) seas wheras QMII and Titanic were designed to get across the North Atlantic quickly, no matter the weather.
You have to take other factors into consideration as well, such as the free surface effect, the draft, the risk of wear and tear on the spots that sustain the most stress, so on and so forth. You can google the largest vessel and see just how big they are. The last couple of ports I’ve been in, the limiting factor of who can enter the zone is draft. More than a few boats had to wait for high tide before they berth because they would run aground otherwise
I'm not a physicist, but this post just brought back a question someone asked our physics teacher when I was at school. We were discussing the (then) largest ship that had ever been built, think it was the QE2 or something, and someone asked if it was long enough would it snap in two because of the curve of the earth?
If I remember right his answer was that the ship would have to be heavier as you get towards the middle so that the buoyancy line (I've just discovered it's known as the plimsole line) would be deeper there and allow either end of the ship to still touch the water. Buoyancy isn't affected by depth so as long as the entire length of the ship is supported by water then there is theoretically no limit to the length a ship can be.
An extra note is that while we may be physically able to build larger ships, many ships are built to standards like "Panamax", in order to use infrastructure like the Panama Canal, Suez Canal, etc.
In terms of the laws of buoyancy, no. Until you hit the volume of the entire ocean, displacement will continue to operate the same. There's definitely a point where the physics surrounding our current shipbuilding technology will fail. Bulk carriers already have a problem with breaking in half from the force of the waves if they're not taken care of properly. There's a point where something becomes so big that modern materials cannot handle the stresses imposed by moving through the sea.
>Bulk carriers already have a problem with breaking in half from the force of the waves if they're not taken care of properly https://m.youtube.com/watch?v=3m5qxZm_JqM
That's not very typical.
I didn't even have to click the link to have a suspicion what it was, but thanks for confirming that.
I didn't even have to click the link to hear every single line in that video, it is ingrained into my mind
At sea?! Chance in a million…
Million to one chances crop up 9 times out of 10.
I like this.
Check out the novel Guards! Guards! by Terry Pratchett. Not only is that phrase from it, but the entire Discworld series is loaded with insightful commentary and humor. It could suck up years of your life in a great way. Here's a 3 minute video with Pratchett! https://www.youtube.com/watch?v=jDF4AHZFQdw
I like how million to one chances crop up several times in the Discworld series. With an acknowledgement by all involved that its a guarantee of success
If there are a million ships on the sea every day, then a one in a million chance is an everyday occurrence.
Which million? Well. Microseconds, mostly.
Can't make it out of cardboard now can you?
Cardboard derivatives always gets me
"All there is is sea and birds and fish... and 20,000 tons of crude oil. And a fire" is always my favourite
_But it's been towed out of the environment!_
Is that common? Oh heavens no. Most boats are engineered so the front doesn’t fall off
"A wave hit it." "A chance in a million!"
personally i like "what's the minimum crew?" " well, one, i suppose"
No paper, no string, no sellotape.
Cello. As in cellophane. Sellotape is a British brand of cello tape. Don't know whether it is sold in Australia. In America, one typically calls it Scotch tape, even though that's also a brand name for 3M's version of cellophane j tape. The short form cello tattooed is not used in America.
Well you’ve guessed where I’m from then, and yes we did export sellotape to the colonies apparently.
Cello tape. Ludicrous. What next, violin tape? Tuba toothpaste? Steam kettle drums? Sod off.
Who orchestrated that?
Pretty sure I've bought a tuba toothpaste before.
Cello No, you thinking of the string instrument. Voila.
No, that’s French for “there it is”. You’re thinking of a Ukraine.
No, that's the breadbasket of Europe You're thinking of a Chicharron
Whoop, voilà!
In America we use duct tape for ship building.
Much safer. I once convinced a friend that due to it's cheapness and durability duct tape is used to help heat shield spacecraft on re entry. I said it as a throwaway joke, didn't really think he'd believe me, but I must have been convincingly deadpan because the next day *his* best friend came and found me and relayed this amazing fact they'd just learned about spacecraft. I was at a music college for rock and pop bands, there was a lot of Spinal Tap-esque characters. When I think about that incident charitably I tell myself that they were probably stoned.
Tbh they’ve made boats out of ice before :)
Pykrete! The material of the future!
Habbakuk!
Also concrete. Google concrete ships of ww2.
several of those concrete ships became piers, I loved to visit the one in Santa Cruz, CA, I vaguely remember being able to go the whole length of the ship (Bow to Stern) I believe it finally broke up in around 2001 http://localsantacruz.com/history/history-seacliff-beach-cement-ship/
Funny story, when Japan released the (fake) public figures of the Mogami-class cruiser, the Director of Naval Intelligence reportedly said "they're either building their ships out of cardboard, or they're lying." It turned out both were partially true in a sense; the Japanese had lied shamelessly about the true displacement, while the ships themselves were notorious for flexing and being too lightly built.
For those who don't know, Japan wasn't lying and saying the ships were bigger, but actually smaller than what they really were. This was in an attempt to skirt global naval treaty limits which limited the size and armaments of warships.
Love you, it was a joke from the video,I'm not even close to OG.
Or cardboard derivatives.
Cardboard's out
Not with that attitude!
What's the minimal crew?
Oh, one I suppose.
Well what happened in this case?
Well, the front fell off
No sir front usually does not fall off
How is it untypical?
Guys! r/silveredFlame is not joking. They really can crack in half... https://youtu.be/gaZhnNlutuQ
Absolutely ludicrous, these are very very strong vessels.
This vessel in particular was: - built for river/lake transport, but operating on the black sea - almost 50 years old - inspected and found lacking and barely seaworthy 2 years earlier 7 crewmembers were killed.
So what do you do to protect the environment in cases like this?
You tow it out of the environment, of course.
Into another environment?
No, it's been towed beyond the environment. There's nothing out there.
WTF did I just watch.
The front fell off
Yeah, but how did it break?
A wave hit it.
Is that unusual?
Oh yes, definitely. 1 in a million.
At sea?!
I just don’t want people thinking that tankers arnt safe..
You’re one of [today’s 10,000](https://xkcd.com/1053).
Welcome to the internet. May I introduce you to goatse next?
Welcome to The Internet! Have a look around.
I loved this but im so confused I feel like it must be a skit , just the way they go back and forth, however, i feel like if it is a skit, its referring to something? Please help
https://www.snopes.com/fact-check/the-front-fell-off/ > the parts of the politician and interviewer being played by Australian television comedy duo John Clarke and Brian Dawe as **they discuss an oil spill that occurred in 1991 when the Greek tanker Kirki lost its bow off the coast of Western Australia**. tbh I had always thought that just the "front fell off" guy was an actor and the interviewer was a real interviewer who was taken hilariously out of context.
Those two were doing saterical interviews in that format for almost a decade before John Clarke passed away in 2017. If you haven't already, search YouTube for "Clarke and Dawe", there's a huge collection of their old videos. Their commentary on Quantative Easing from the GFC is a particular hilight.
> Those two were doing saterical interviews in that format for almost a decade before John Clarke passed away in 2017. _______ >as they discuss an oil spill that occurred in 1991 Sounds like quite a bit longer than "almost a decade"...
You're right. [According to wikipedia](https://en.wikipedia.org/wiki/Clarke_and_Dawe), what I meant to say was "for the better part of three decades" > Clarke and Dawe (also stylized as Clarke & Dawe) is an Australian news satire television program that originally aired on the Nine Network from 1989 to 1996 and later on ABC TV from 2000 until 2017.
Good thing they met the minimum crew requirements! One of my favorite bits ever!
I've never seen this before, so good!
This is hysterical. What a treat.
I can imagine this as a Monty Python sketch. I can’t decide who should play either of the two roles. Chapman, Cleese, Idle, and Palin could have pulled off either role. I can’t really see Terry Jones, though.
Yes, Minister/Yes, Prime Minister is definitely a similar vibe too, if you want a whole series of this type of thing
[Utopia](https://youtu.be/MTCqXlDjx18) is bloody hilarious too, and more modern
I’m so glad this link was to that video
r/thefrontfelloff
Absolute gold! I miss John, love Fred Daggs!
Oh, I was hoping that would be a link to that video!
I can’t tell if that’s real or not lol funny nonetheless.
It's a comedy sketch about a real incident.
Didn’t even have to click the link to know EXACTLY what video it was haha 😂 Perfect.
Fully prepared for this to be "the front fell off"
I love him LMAO. The environment just ends, suddenly, on the way to the middle of the ocean.
I could swear I just recently watched a video of a us politician doing the same circular logic but for real
That clip never ever gets old! Very apt.
Excellent response. I have served aboard Aircraft Carriers and they have expansion joints built in, to allow the ship to flex.
Waves would probably be less of a problem on a huge ship with significant draft. If the wave height is negligible compared to the draft and roughly the same volume stays submerged all the time, there won't be as much shear stress on the hull. Of course if the size and draft are too big then the question is what you would actually use such a ship for, because you either have to design ports to accommodate that huge ship. Or just never dock anywhere at all.
it's not the wave height that's the issue, it's the wave length. What makes the container ships break apart is from 'hogging' and 'sagging'. If wave tops are at the front and end of ship and the wave trough is in the middle, it causes ship to bend down/sag. Likewise if wave troughs are at port/stern of boat and wave peak is in the middle. It causes repeated stresses that eventually break the ship apart.
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My cruiser steamed through a class 4 typhoon because the captain was an idiot. Most frightening night of any of our lives. Lost guns, antennas, hatches, the ship's bell. Pictures from the bridge of the bow just... gone; fully submerged. Their were definitely moments where the ship righting itself wasn't assured. The Captain got reamed by an admiral over the primary radio channel, which is completely unheard of.
How does that happen in the modern era? Can you have a surprise typhoon? Can a vessel sneak off on an unapproved cruise?
Lazy captains are usually the reason for this sort of thing.
I guess the captain was thinking: "Class 4 typhoon? Pfft. She can take it!" And I suppose he was right.
That sounds terrifying as hell, but it also sounds like the super cool experience you tell your grandkids about.
Wow that sounds scary. Do you know of any instances of modern military ships being lost at sea from violent storms?
Yes. In World War 2, Admiral Halsey sailed the Fifth Fleet into not one, but two Typhoons. Several destroyers were lost, because he had refused first to allow them to refuel early because he thought the Typhoon would pass by, and then when he realized too late that the storm was going to hit the fleet directly, the destroyers lacked the fuel to maneuver how they would need to in order to ride out the storm. At the same time, the fuel in destroyers of the day was ballast that gave the ships stability. Without that fuel, they were top heavy and prone to rolling over in heavy seas. Several destroyers and hundreds of men died. There was another even where a US Navy cruiser that had been damaged in battle foundered and sank on the way back to the US for repairs in a heavy storm. One of the risks that they had to take then was sailing all the way back to the US or Hawaii because there just wasn’t enough infrastructure in the South Pacific to repair battle damaged ship. Even Australia lacked the necessary shipyards to do more than temporary patching, which didn’t always hold up to rough seas.
Re: that first one, they also nearly lost a carrier and a certain officer named Gerald Ford in the process. That certainly wouldn't have had any major ramifications in politics later.
Nah, that sounds like the car guy. Henry Ford was the president, I'm sure of it
Or or or how about his one. You don't even have to open it just read the link. https://www.businessinsider.com/how-george-hw-bush-avoided-being-eaten-by-cannibals-in-world-war-ii-2017-12
Halsey acted stupidly.
With modern weather forecasting, they simply avoid it. Heck, they don't even like them in port for big storms. Norfolk, VA it's a thing there when a hurricane is coming towards them to go watch the parade as every Navy ship that can put to sea puts to sea in order to get out of the way of hurricane -- and that's from Hampton Roads, one of the world's best protected harbors. https://www.youtube.com/watch?v=CMlgNjqSHHo
will they blow the ship horn like truckers do if you wave at them
A quick Google search found a Thai naval vessel that sank last year. It was 40+ years old. Cause was due to heavy weather, water entered the air intake for the power generation and shut down all the engines. Once those are gone, it is just a matter of time before a vessel sinks due to not being able to maneuver.
In the run up to WW2, Japan knew they were never going to win numerically, so decided to try and compete on quality of ships. At the same time, they tried to at least have the veneer of adhering to international naval treaties. This led to ships that were very top heavy due to their heavy armament, and with hulls buult with new electric welding techniques to save weight. During an exercise, their 4th fleet was caught in a typhoon. By the end, two destroyers had lost their bows entirely, nearly all destroyers suffered damage to their superstructure, two of their new heavy cruisers developed serious hull cracks, and two of their light carriers suffered damage to their flight decks.
Same, been in waves that were 30', but spaced really far apart. It just rocked us to sleep. But also in 15' waves across the beam and high winds, shook as all around and everyone was seasick.
If the draft depth is substantially deeper than the tallest wave, it won't matter (because even if there are two peaks at opposite ends of the ship, with a trough in the middle, a "peak" barely lifts with any force).
I mean, if you take that logic far enough, you begin to describe a submarine. So sure, but suffice it to say they have their own engineering challenges :D
My point was if the draft is significantly larger than the wave height then the effects you're describing become negligible. The hull will remain significantly underwater and will not experience much bending or sagging.
Sure, but that would have to be a ludicrous size, as waves can get absolutely massive in the deep ocean.
Is that not the point of the conversation though?
Allow me to introduce you to my friends "drag" and "fuel economy"
There's a funny thing about drag and the length of a ship, though. Generally the longer a ship is the faster it's able to move because of a reduction in drag. Look up "hull speed".
What is draft? How low the ship sits in the water?
I believe it means how much of the ship is below water, or like how deep under the surface of the water the keel of the ship is typically meant to be.
Just make it a submarine. Your waves have no power here.
Checks out, this person has solved it.
Yes
Ok, new plan, giant cargo carrier that uses normal cargo ships to ferry things into and out of ports. Impractical? Yes. And environmental catastrophe in the offing? Absolutely. But can one really put a price tag on having a ship so large that the far end is below the horizon?
How about we just build a network of giant dry canals in the ocean and drive trains on the sea floor? THIS IS MY IDEA ELON DONT STEAL!
Sounds good. But best I can do is [a shitty tunnel full of Teslas.](https://archive.curbed.com/2020/7/23/21334351/elon-musk-boring-company-las-vegas-tunnel) Yours, -Elon
We will call it a hydroloop! -E
Soooo a shipberg? That’s quite an image.
So, the mass of every ship in the world is roughly 0.000000015 percent of the mass of the ocean.
Have you ever seen waterworld??
Technically speaking, all the ships in the ocean cause the sea level to go up a tiny bit right? Or is it so negligible that it basically doesn't change?
Yes, and yes. It's estimated that the global maritime fleet is roughly 2.2 billion tons, or 2,200,000,000 tons. The oceans of the world are roughly 1,450,000,000,000,000,000 tons. So, the mass of every ship in the world is roughly 0.000000015 percent of the mass of the ocean.
But we wanted an answer in decimal inches. ;)
football stadia x hertz
Using the above estimates, we divide 2.2 billion tons of ships by the density of water (15974.36 drams per cubic foot) to find that ships displace 405,098,901,000,000 teaspoons of water globally. We then divide the volume of water displaced by 430,566,400,000,000 square yards (the surface area of the ocean). As a final result, we get that the oceans are raised by precisely 0.000218356783 inches.
...but it only counts if it's in bananas or half giraffes.
Some giraffes can grow up to 18 feet but most only have 4.
This guy giraffes!
I believe half giraffes are industry standard. But don't quote me.
I was gonna say 0.000000015 is more than I expected, but then realised it's like 15 trillionths.
[https://what-if.xkcd.com/33/](https://what-if.xkcd.com/33/) answers your question :)
If nobody got me I know xkcd got me 💪😤
> Bulk carriers already have a problem with breaking in half from the force of the waves if they're not taken care of properly. There's a point where something becomes so big that modern materials cannot handle the stresses imposed by moving through the sea. This isn’t really accurate. Large bulk carriers and tankers operate just fine. A tiny handful of failures have occurred that make the headlines but there is no generalised problem with stresses on very large cargo vessels. Further, the problems that have occurred have been due to design failures in the early days of building such large ships, and certain unwise cost savings made in construction. We haven’t even begun to approach the maximum theoretical design strength of steel in shipbuilding design. The reasons ships aren’t made bigger are economic and practical, not structural
The largest cruise ships are still only at about 362 meters, compared to the, by now, standard for megamax container vessels of 400 meters... So yes, they can get bigger, but you also need to make sure you have a business for that many people Many places are starting to limit the size of calling cruise ships, ie the Galapagos only allow ships with 100 or less passengers if I remember correctly For container vessels it would probably be something like the Suez canal that limits it, but I think the next advance in that field will be one or two more rows. Currently they are at 24 rows, dubbed megamax-24. I have heard a rumor that a gigamax-25 has been pre approved by a classification society. The largest cranes can theoretically take 27 rows For tankers (and dry bulk) it would probably be the depth somewhere that limits them. But as the biggest usually are build for a very specific trade you can get around a lot of the most notorious limitations if you want ie Malaga Strait It would for most not be the buoyancy that is the limit, but the stress factors (Share Force, Bending Moment and Torsion) and keeping a legal, positive GM (distance from center of Gravity to Metacenter height, a number for the ability to upright itself) for the cruiseship and the empty tankers Hope this answered a few things Source: second officer on a merchant vessel
Where is the Malaga strait?
I believe he mistyped Strait of Malacca, just as he wrote “share force” instead of shear force.
This... Is what happens when you type it out in 5 minutes on the toilet and not looking any thing up...
One of the more informative poops I've heard of so thanks for the effort
It depends. If we are talking hypothetically, no, as you could hypothetically put a ship on a perfectly flat plane of water with no disturbances, and it would be fine. In reality, things like waves, the load of the ship, moving the ship, and the structural materials the ship is made out of all limit the size. Buoyancy doesn’t have a limit, all you really need is to displace water to force the ship to float.
And yet, the mega ships we're building today would've been thought impossible mere decades ago, but here we are. If there's a limit, it'd be return on investment.
One major limitation is the dock facilities. Massive cruise ships require huge docks that can accommodate their length and draft, and it’ can be expensive and inconvenient to continue expanding existing docks.
And depth of ports - deeper drafts to account for larger displacements will block access to many potential ports of call (I’m looking at you, VLCCs).
Yeah. Eventually we won’t be able to produce a material which can handle any more stress, but at that point it would be better to just make more little ships, or make a “raft train.”
People round the world, join hands, start a raft train, raft train
well, just adding a lot of steel frames and reinforcements where needed works, especially with the help of computers to simulate stresses. Engines become more efficient the larger they get, and larger ships have relatively fewer crew. I'm sure there's a limit though, but theoretically, no.
But that’s added weight, which needs a bigger hull, which needs more supports, so the cycle continues until something snaps.
the limit we had on size when I worked at Mærsk was the capacity of the docks to be able to load/unload from the ship. If the crane can't reach because the ship is to large on any given axis or if the draft is too deep? then you have a problem...
Yep. And there will always be a few ports that are able to handle them, like Rotterdam for instance, we're among the first to have the new generation of cranes for the new mega carriers, and was one of the few ports in the world that could handle the vale super ore carriers. But they're mega investments, hence the limit on ship sizes is a ROI one. Also you must be a Dane, using the correct spelling of maersk, apart from having worked there of course.
Theoretical, the sphere of the earth would be your only real limiting factor, unless you made a ship that acounted for the curved shape of the earth, then your limiting factor would be the length of the sea.
The longest distance between two landmasses would be the theoretical limit at which a ship becomes a bridge.
Or we make a ship that bends (like an S shape) to take up more room, but that would be stupidly impractical.
or build lot of small ships, we'll call them 'rail cars', all connected end-to-end, being propelled by a large Engine car in the front, and a caboose in the back.
Now you're just being crazy.
Sooner or later you're just going to be splitting hairs on the difference between "Really long ship that stretches from New York to Ireland" and "Really long pontoon bridge"
Yeah. That’s why I said hypothetically, because it’s possible that we create/find a planet which is massive, and has only water on the surface.
Flat Earthers disliked this
Then the limit to the size of the ship is the edge of the world. Either way, you run out of Earth.
Not really. All of those factors get easier to design around the bigger you get. The biggest factor limiting ship size is harbor depth and dock size (as well as canal size depending on route). If the infrastructure and demand supported it, ships would be big enough to match. Edit: I forgot shipyard/dry dock size as a limiting factor.
I think at some point the literal curvature of the earth (or whatever planet you are on for the pendants) becomes a limiting factor.
Boyancy isn't an issue as it is related to the "hollow" volume inside the ship and the Archimedes principle https://youtu.be/bKToF_t5LAU The major issue as you get much larger is shearing stress on the metal frame where the hull could potentially fracture and let the water in.
Even then, you could just make the ship flexible. Kinda like those bendy busses.
I was thinking something similar - like a train of smaller hulls underneath, but on top was a large platform that supported the living/cargo section of the ship
Why not just make a ship train then? Engine at the front, several sections following behind, minimal crew ( ͡° ͜ʖ ͡°)
>( ͡° ͜ʖ ͡°) Sir what are you intentions with the floaty train??
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But it won’t disagree, because of the implication…
Ships are flexible. Everything large is flexible.
Mostly just practical limits. *Seawise Giant* was too big to navigate the English Channel or the Suez or Panama Canals. There's just not many reasons to make a ship that big.
TIL about *Seawise Giant* and *WOW* - the thing was literally the size of the Empire State Building! That’s absolutely mind-boggling
As many others pointed out "Sea Worthy" and "will it float" are not the same thing. Also at some point you start to strain the idea of calling it a ship. The ocean is not flat, it moves around a lot. At some point you run into mechanical limits of a rigid structure, if you had a "ship" that was 10 miles long and the front end encountered a storm that blew it violently in one direction while the back end was still like an hour away, if your vessel as rigid or even semi-rigid, it would tear in half. But if you don't limit yourself to what we normally think of as a "ship" you could, at least in theory, do all kinds of crazy large scale things. For example you could create a series of large floating "nodes" connected by flexible pathways and spooling/retracting cables that allow it to bend and move and change shape with the ocean conditions. If it could very very slowly move around the oceans using some combination of sails and motors, a kind of large floating migratory city, that could become enormous. But is that really a "ship" at that point? And of course even if you could do it, is it feasible?
If it were still long like a ship, I can't imagine it wouldn't coil up like a snake. Might have to be approximately circular, in which case it's really not going to want to move against currents and would probably wind up crashing on shore. What a weird thought experiment.
ELI5 - MONEY, ECONOMICS, EFFICIENCY, INFRASTRUCTURE, STABULITY restrict how big they can get. Not a naval architect but used to work in the merchant navy on container ships. To my understanding, there's no real theoretical limit, they can keep getting bigger and bigger on paper. I worked on MV Erving, which was 366m long (~1200ft) and could hold 16000 containers. Back when it was built it was about getting as much cargo from one place to another as fast as possible. It had a huge engine (2 stroke diesel that created 75000kw of power) cause back in those days that is what the goal was. Now it's all about economics and saving money. Most high streets still need the demand of things getting from one country to another as fast as possible, but it isn't money efficient and its better for shipping companies to take a little longer but in the meantime save on fuel. My ships was spending roughly $2.5m every 2 months to refuel. Money aside, there are other major infrastructures to be majorly aware of, such as the Suez and Panama canal. They save the shipping companies a lot of time and therefore money on fuel, and allow shipping companies to make more money by being able to deliver their cargo and get new things in the shop a lot quicker than going round the capes of South America and South Africa. Ships are often restricted to the dimensions of these canals and ships are even named after this such as PANAMX containers, meaning the maximum size of a ship to fit through the Panama canal. Another issue with making bigger ships that a lot of people aren't aware of is the depth of water around ports. The ship I worked on was so big that we were restricted into what ports we could enter due to fear of grounding so if ships were made bigger, they would have a greater draft and therefor would run higher risks. While larger ships can potentially carry more cargo or passengers, there are limits to the efficiency gains. Beyond a certain size, the economies of scale may diminish, and other factors such as loading and unloading times, port infrastructure, and operational complexity may offset the benefits of increased size. Lastly is overall stability, even the ship I was on, when it was fully loaded, and we had some bad weather, it would roll like crazy. Like most things made from metal, they are designed so that they bend and flex. I imagine there comes a limit to this, longer something is, the more it can bend/flex but yeah, within limits for it to still remain safe. Unfortunately I don't know much about cruise ships, personally I think they are unnecessary and would advise people to read up on how much they pollute, but yeah hopefully that helps give a bit of insight for you!
The size of the biggest ships is usually limited by the route they are traveling. For example, if they have to fit the locks in the Panamacanal. These are called 'Panamax ships' and they are amongst the biggest they build.
Panamax are actually among the smaller classes of ships. Post-Panamax and Capemax ships that transit around the Horn/Cape of Good Hope instead of through one of the canals are much larger, and there's plenty of ships that just go between continents without needing to hit a canal and are larger than Panamax.
Adding to your post: This is exactly why ships are called stuff like panamax, suezmax, supramax and several more \*max. They are made to fit within specific limiting parameters. On the open sea, they are only limited by what can be safely built within a budget.
The limit would be the structural strength of the materials used to build the boat. (As well as the size limit for being able to fit in ports) There is no "buoyancy" limit, being able to float simply depends on displacing enough water to match the weight of the boat.
To be useful in the Northern Hemisphere a ship needs to fit through the Panama Canal. Recently upgraded locks allow for ships up to 51.25m/168 feet wide and 366m/1201 feet long.
There is not really any limit to how big a ship can be. If there were a biggest ship hull that was possible you could just take two of these hulls and connect them together to make one twice as large. So there can not be a largest theoretical ship size. In fact the current largest ship are kind of doing this. It have the hull of a super container ship but have two hulls connected together with big cranes mounted on top of it.
The only limit would be the physical resistance of materials. But if you manage to build something like a very large plate, for instance, with high borders, you can make it an insanely large ship. You merely have to get materials which will resist the huge torsion forces from having parts dangling, while other are pushed by waves, the parts in question changing with the underlying waves. So, the current sizes are determined both by the sizes of the bodies of water / harbors (because, if you need 150m underwater and 800m abreast to be able to navigate, it *might* cause a few problems to reach a harbor, or to use channels, etc.), and by the economical use. If you plan to take 10k passengers, a ship maybe 20 or 30% larger than what we currently have will be enough. If you want to take 250k passengers, you'll build larger. Same for cargo: If you need to take 100 times the number of "boxes" a very big container transport does today, then yep, maybe you'll build larger. But, then again, you'll need facilities which can accommodate such a giant ship. And unless several ports invest in order to be able to do so, you won't be able to use your ship, in practice. Considering the cost of a ship, you don't want to build a giant you cannot use. So, the limits are more because of economical and practical constraints, than physical ones.
When the hull is dragging along the bottom of the Mariana Trench, you've reached your limit.
Us navy veteran here. I suspect the practical limiting factor would be not the ship itself but port facilities. Ships need to tie up pier side and on Occasion get serviced. If there is a big enough space that’s a problem. Oh. Also insurance. Ships must have insurance. For a mega gigantic ship the insurance rates might be prohibitive.
Royal Caribbean keeps making basically the same ship but a couple meters longer, so each is the new "largest ever" cruise liner...
For cargo ships, the practical limit is the size of the Panama and Suez canals. Ignoring those factors, you need to worry about waves and wind and the depth of the ocean where you want to make port. There's nothing about floating that gives us a limit though.
The biggest issue for ship size is where you put them. Shipping ports are constantly upgrading to allow larger and larger ship. But if there are currently no points that can handle your ship, you can't do anything with it.
Other considerations are ports large and deep enough. Height would be limited to any bridges it would need to navigate beneath - or canals it needs to traverse.
Couple of things… since I’ve been tangentially involved with several of Royal’s new builds… If you’re talking about *Icon of the Seas*, they didn’t “just give the go-ahead”, that ship is less than 3 months from completion and will enter service in January. They take about 3 years to build following another 4-5 years to design and do the engineering on (which is why when they design one, they usually build at least 3 of them. Designing a ship is expensive af). In terms of size, Icon Class is only a few feet longer than their existing Oasis Class ships, and a few feet narrower (called “beam”). In terms of overall size, it’s comparable to some of the very large container ships. The only real constraints to size are needing a dry dock big enough to accommodate the construction (and later, repair and maintenance), and you have to be able to get it from the yard to the sea - Icon is being built at the Meyer yard in Turku, Finland, and getting from the Baltic to the ocean involves getting under a bridge on the west side of Denmark that has a maximum clearance (also called “air draft”) of 57m. Ships built in other yards don’t have that limitation. The ships also have to be able to put into the various ports of call, where the channels need to be deep enough to accommodate the approximately 9 metres of ship that is below the water line (called “draft”) and be able to maneuver the ship in those conditions. For some ships, they also have to be able to fit in the locks of the Panama Canal. When you see a measurement like “Gross Tons”, that’s not a measure of weight, but rather one of *volume* (of the enclosed portions of the ship). This is more of an administrative metric that guides things like number of lifeboats, passenger capacity, minimum crew, taxation, and so forth. The actual weight of a ship is considerably less since most of the enclosed space of the ship is just empty space filled with air. A surprising amount of that space is actually dedicated to air handling and ventilation throughout the ship. A ship the size of Icon probably has an actual mass of a little over 100,000 tons.
Ships that size have been traversing the seas for years. [Ultra Large Crude Carriers](https://www.wikipedia.org/wiki/TI-class_supertanker) carry around 400,000 tons of oil and are around 1200 ft long. They are so large that they are effectively at sea their entire lives and can only moor to pipeline piers further out.
the ice at the north pole is floating. it's pretty big, I'd say. so no, you can have a really big thing float.
Main limits are port depths, dock sizes, and shipyard sizes. And at least with passenger/ cruise ships, they've mostly grown taller and wider over the years. Just compare Titanic to Queen Mary II. QMII is less than 200 feet longer than Titanic but about 1.5x as wide and 1.5x as tall (from the keel to the top deck not counting the funnels) iirc. Cruise ships are even bigger than QMII because they're leisurely cruising around calm(ish) seas wheras QMII and Titanic were designed to get across the North Atlantic quickly, no matter the weather.
You have to take other factors into consideration as well, such as the free surface effect, the draft, the risk of wear and tear on the spots that sustain the most stress, so on and so forth. You can google the largest vessel and see just how big they are. The last couple of ports I’ve been in, the limiting factor of who can enter the zone is draft. More than a few boats had to wait for high tide before they berth because they would run aground otherwise
I'm not a physicist, but this post just brought back a question someone asked our physics teacher when I was at school. We were discussing the (then) largest ship that had ever been built, think it was the QE2 or something, and someone asked if it was long enough would it snap in two because of the curve of the earth? If I remember right his answer was that the ship would have to be heavier as you get towards the middle so that the buoyancy line (I've just discovered it's known as the plimsole line) would be deeper there and allow either end of the ship to still touch the water. Buoyancy isn't affected by depth so as long as the entire length of the ship is supported by water then there is theoretically no limit to the length a ship can be.
An extra note is that while we may be physically able to build larger ships, many ships are built to standards like "Panamax", in order to use infrastructure like the Panama Canal, Suez Canal, etc.