This is the Seaspan Harvester. It's a log barge that operates off the western coast of Canada. When it's time to offload its cargo of logs, the crew shifts the ballast inside. The ship tilts 30º and the logs slide off. Here's a video showing it in action.
The Seaspan Harvester is a barge. It doesn't have an engine, so tugs move it as needed.
-via Jalopnik