I recently read an article that the Royal Caribbean have just given the go ahead for the largest ever cruise liner to set sail, it’s nearly 1200ft long and has something ridiculous like 5 water slides and a zoo on it (maybe that’s an exaggeration, but you get the point).
It got me thinking – is there a ceiling to how large a boat can be? Does buoyancy have a limit? If you ignored the impracticality of mooring and getting into smaller bodies of water, is the capacity of Ship building limitless?
In: 2380
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.
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.
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.
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 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
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.
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.
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.
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.
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