Does anyone know if the containers interlock in some way? I figure that they don't, because that would make it more difficult during unloading.
I get that the bottom and middle containers are held in place by the hull or the "racks", but the top contains seems to just be sitting there held in place only by their own weight.
A great book to learn all about the history of shipping containers, container ships, and the technical innovations involved therein, is The Box by Marc Levinson.
They are attached to each other and the ship via some mechanism that interacts with their corner castings. (Each corner has a box with slots in it.) Turnbuckles, twist locks, rails, etc are used to secure the containers.
The Box by Marc Levinson gives a great history of the move of sea freight from bulk storage to containers, and the various companies and players instrumental in this change.
Not technically a ship, but those interested in this story might be interested in the Prelude, which is set to be the world's largest vessel. It will dwarf these ships...
That's the biggest container ship; I believe the world's biggest ship of any kind will be 488m long ... a natural gas processing vessel which will eventually be docked off the coast of north-west Western Australia.
I think you should visit a terminal. The cranes used to load and discharge containers are massive. Often much bigger than any existing vessel as the vessels keep getting bigger. See for instance cranes being shipped on a vessel: http://www.schoonerwoodwind.com/wp-content/uploads/2012/06/c.... Now try and discharge+load e.g. 1000 containers.
In your suggestion did you consider:
* how would a smaller ship be able to offload a much bigger ship
* speed of loading+discharging matters a lot and a smaller ship will be much slower
* where to store the containers
* impact on transhipment
There are vessels with cranes on them, those are usually not full container ships but more like vessels which mostly handle trucks+cars plus occasional container or breakbulk cargo.
The latest terminal in Rotterdam has switched to working remotely with camera's because it has become impossible to put anyone on a crane, see e.g. following video. Dutch, just look at the monitor screens they're using:
http://nos.nl/video/2011857-wereldprimeur-in-rotterdamse-hav...
It could be done at sea, but it would add too much time and time is extremely valuable with ships this expensive. These ships make money transporting goods, if they aren't moving containers they're losing money.
Do all of the containers sit on top of the ship? What's in the hold? Is it just more containers? Are there refrigerated sections? Frozen sections? Tanks?
To add: Those reefer containers have to be stored in a special section of a vessel (where they can be plugged into power). Frozen vs refrigerated is just the temperature setting. These reefer containers are usually to keep the temperature of a product. Meaning: they're not meant to freeze a product to e.g. -20 Celcius, though "not meant" and practice can differ a bit :-P
I get that the bottom and middle containers are held in place by the hull or the "racks", but the top contains seems to just be sitting there held in place only by their own weight.