Canadian Coast Guard sailors assigned to CCGS Edward Cornwallis prepare to recover a Zodiac boat carrying Royal Canadian Mounted Police divers supporting a maritime intervention operation during Exercise Frontier Sentinel 2012 May 7, 2012 at sea off Sydney, Nova Scotia. Exercise Frontier Sentinel is a combined interagency exercise involving Joint Task Force Atlantic, the U.S. Coast Guard and the U.S. Navy Fleet Forces Command. The exercise is designed to continue to develop and validate the existing plans, treaties and standard operation procedures for a bilateral response to maritime homeland defense and security threats.