Officer in tactical command (OTC) is a NATO term used to designate the naval officer exercising tactical command of a group of ships in a tactical formation such as a task unit, task group, or task force. Ships travelling together on a specific mission might have one of the commanding officers designated OTC. On occasions an officer senior to the ship's captains (a senior captain, a commodore or an admiral) will be embarked specifically to take command of the formation, and in thise case, he or she will exercise the function of OTC..