We've seen reports of users having issues with the game freezing up when entering water. If you're having this issue, head to the PlayStation XMB menu. From there go to Game>Game Data Utility. Delete the game data and title updates for Skyrim.

Note: Game Data is not the same as your game saves. As long as you're not deleting anything from the game saves folder, you'll still have your saves.

Once you restart Skyrim, you'll need to wait for the 1.8 title update (listed as either 1.08 in North America or 2.08 in Europe) to reinstall, as well as the mandatory game data install.