How container ships are made

A container ship is welded together from prefabricated blocks and lifted into a dock like a giant kit.

stations: 9
things upstream: 68
raw sources: 23
steps from the ground: 10

The short version

A container ship is built in blocks. Steel plate is cut, welded into flat panels and then into multi-deck hull sections, with pipes and cables already installed. A crane lifts each block into a dry dock, where they are welded into a single hull. The engine, propeller and cargo guide rails go in before the ship floats out.

Cut the steel plates

Steel plates are marked and cut to the shapes of frames, decks and hull skin. The ship's frames run at right angles to its keel, and the deck beams rest on top of them.

Goes in
Steel
Weld flat panels

Plates are welded into large flat panels, which are the walls and floors of the future hull. Modern yards also use deep-penetration welding that fuses thick plate in a single pass.
Build the hull blocks

Panels are joined into whole sections of hull, several decks high. The most modern shipyards pre-install pipes, cables and equipment inside each block, so that little work is left deep inside the finished hull.

Goes in
Steel pipe Copper wire
Lift blocks into the dock

Cranes carry each block to the dry dock or slipway and set it in place against its neighbors. This is called block construction.
Weld the hull into one

The seams between blocks are welded, turning dozens of sections into a single watertight shape.
Fit the cargo guides

The hull is like a vast warehouse divided into cells by vertical guide rails. Containers slide down between the rails and stay put in a swell.

Goes in
Steel
Paint below the waterline

Hull plates are blasted, primed and covered in coats of paint that keep out seawater and slow the growth of marine organisms.

Goes in
Paint
Install engine and propeller

A very large slow-turning diesel engine is lowered into the engine room and linked to a single large propeller.
Float out and sea-trial

The dock is flooded and the ship floats free. It is then sailed on trials to check speed, steering and fuel use before the owner takes delivery.

End of the lineContainer ship

Worth repeating

A ship delivered to MSC in 2023 holds 24,346 TEU, and measures 399.99 meters long and 61.3 meters across.
About 90 percent of the world's non-bulk cargo moves in containers.
In the years 2011 to 2013, an average of 2,683 containers a year were reported lost at sea.