Tropical Storm Bonnie is moving in on the Gulf—and bringing with it complications for BP's oil spill clean-up. Crucial ships are being forced to evacuate the site, including the rig that’s responsible for drilling a relief well that the company hopes will ultimately plug the spill for good. "While this is not a hurricane, it's a storm that will have probably some significant impacts, we're taking appropriate precautions," Coast Guard Admiral Thad Allen, who is coordinating the response, said in Alabama today. Only some of the ships will stay, Allen added, in a development that will likely delay by 12 days the final plugging of the well. While the ships are gone, BP will leave its cap on the well, a confident sign that it is plugging the leak effectively. Vice President Joe Biden, who is visiting the Gulf, kept an optimistic tone: "After the storm's passage we will be right back out there," he said.