http://www.gamesas.com/topic/1364560-game-freeze-after-going-underwater/
I did this, and it worked.
Ah thank you, I didn't notice the stickied thread.
I sincerely hope that 1.6 contains a fix for this bug that Bethesda introduced in 1.5 or when Dawnguard releases and a bunch of people come back to Skyrim for the first time in months we're going to see a lot more of these threads popping up from people who haven't read the sticky.
Yep, I didn't see the sticky, so sue me.
If a Mod see's this, they can close the thread.