Modern container ships are made from welded steel plates and can have length of up to almost 400 m. They carry huge numbers of inter-modal containers (which can also be carried by truck or train).
The first container ships were converted world war 2 T2 tankers typically 152.9 m in total length and 20.7 m in width (beam). The largest container vessel today is MSC Oscar, 395.4 m in length and 59 m wide and capable of carrying 19224 containers (TEU — twenty foot equivalent unit).
As these ships travel the globe they are bashed by waves, in this video we can see the displacements this causes inside the vessel.
Video shows the container ship MSC Busan in heavy seas. In the video at around 11 s a wave of height approx. 7-8 meters hits the vessel.