I watched this on a whim because it was available and I'd heard the Thumb movies were funny. This one was not. The majority of the jokes were based around "Geranium's" physique and, in turn, Kate Winslet's. I think it's really pathetic of the the "Thumbtanic" creators to stoop so low to make jabs at a respected actress just because she (heaven forbid) doesn't starve herself into the model of ideal modern beauty.
My favorite part was the line that goes something like, "Hey, I have a great idea! Let's swim over to this makeshift raft that no one else seems to see!" Thirty seconds of amusement out of a 26 minute movie does not redeem its value.