Ships travelling together on a specific mission might have one of the commanding officers designated OTC.
On occasion, an officer senior to the ships' captains (a senior captain, a commodore, or an admiral) will be embarked specifically to take command of the formation and exercise the function of OTC.
In port, under peaceful circumstances where there is no tactical situation, the senior officer present afloat (SOPA) assumes certain roles associated with the OTC.
The OTC is only empowered to direct the assigned forces for the specific purposes designated by the officer exercising operational command over the formation.
This article incorporates text from the public domain Dictionary of American Naval Fighting Ships.