
Scandinavian padlocks, also called 'Smokehouse' padlocks, "have been popular since the early 1800's as jail locks and on strong boxes, chuck wagons, stores, farms, etc." -The Padlock Collector, Franklin M Arnall

Included a #3 in there for scale. These things are massive - and larger ones exist.

Several different manufacturers made these kinds of locks, but they are often found without markings, making identification difficult. Note the Star around the keyhole on these.

One has a removable shackle, the other does not.
The overall size, simplicity, and feel of these locks remind me a lot of the S&G Environmental, though their mechanism is quite different. These locks are interesting in that the key has a much more direct relationship with the shackle than most other padlocks - the key rotates massive disks that sit in the slots of the shackle.