The U.S. Coast Guard detained two dozen protesters who formed a blockade with kayaks and other vessels Monday to try to stop Royal Dutch Shell's drill rig as it left Seattle on its way to explore for oil in the Arctic Ocean. The protesters were scooped up from the water because they were violating the safety zone around the Polar Pioneer, which departed around 6 a.m., Coast Guard Lt. Dana Warr said. They would be released after receiving violation notices that carry a $500 penalty, he said. About a dozen "kayaktivists" paddled out around 4 a.m. to try to prevent the 400-foot-long rig from leaving, said Cassady Sharp, a Greenpeace spokeswoman. Several dozen supporters in kayaks and canoes lined up behind them, she said.