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

Task force

A task force is a unit or formation established to work on a single defined task or activity. Originally introduced by the United States Navy, the term has now caught on for general usage and is a standard part of NATO terminology...

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Ships traveling together on a specific mission might have one of the commanding officer

Commanding officer

The commanding officer is the officer in command of a military unit. Typically, the commanding officer has ultimate authority over the unit, and is usually given wide latitude to run the unit as he sees fit, within the bounds of military law...

s designated OTC. For larger formations when a commodore

Commodore (rank)

Commodore is a military rank used in many navies that is superior to a navy captain, but below a rear admiral. Non-English-speaking nations often use the rank of flotilla admiral or counter admiral as an equivalent .It is often regarded as a one-star rank with a NATO code of OF-6, but is not always...

 is embarked onboard one of the ships, the commodore would most likely be designated the OTC.

Purpose of the OTC

The purpose of the OTC is to provide authority and direction for actions the group is to take in the course of assigned operations and to communicate the information to higher authorities.

Limitation of authority

In port, under peaceful circumstances where there is no tactical situation, the Senior Officer Present Afloat

Senior Officer Present Afloat

Senior Officer Present Afloat, usually referred to as SOPA, is a U.S. Navy term to indicate the U.S. Navy officer, with the highest ranking by rank, or number in rank, present in a harbor occupied by more than one U.S. Navy vessel. That officer is essentially commander of all U.S...

 (SOPA) assumes certain roles associated with the OTC.

The OTC is only empowered to direct the forces assigned to him or her for the specific purposes designated by the officer exercising operational command over the formation. The OTC may not reassign forces assigned to him or her for another purpose.