Firat, you need a boat. If you wander around, you will find an icy place. Put your boat on ice and push. While pushing, rightclick so you can get on the boat. If you suceed to get on the boat, the boat will start to sink down, and you will get stuck under the ice.
Duplicate of MC-3761, please use the search function to see if your bug has already been submitted. Currently over 51% of tickets are being closed as duplicate.