Labeled as DUKW or DUCK boats by the tour operators, they are actually a newer better version and are labeled as LARC-V for Lighter, Amphibious, Resupply and Cargo, 5-ton.
We paid to ride on one in Singapore to get a short tour of the city near the harbor, and a tour in the water in the harbor. There really isn’t a suspension to it, just the squish of the massive tires, so it basically rides just like my payloaders.
You can read more detail about them on Wikipedia.
Here’s some pictures:
