During the ICEX 2003 naval exercises near the North Pole, the American submarine Connecticut (SSN 22) poked its sail and rudder through the ice. When an officer looked around outside via the periscope, he noted that his sub was being stalked by a hostile polar bear. The periscope cam was turned on, and these photos of a polar bear chewing on the subs rear rudder resulted. The damage was said to be minor. The SSN 22 is a Seawolf class boat, one of the navys newest submarines. It wasnt designed as a polar bear snack, but thats how life is sometimes.
http://www.strategypage.com/gallery/default.asp?target=bear_sub1.htm
