The USS Royal Oak (NCC-2013) was an Excelsior-class battleship in service to Starfleet in the 23rd and 24th centuries. Royal Oak was constructed at a time when she and sister ships were being named for naval ships of Earth's history, Royal Oak in particular for a ship of the United Kingdom's Royal Navy from the era of World War II.
The Royal Oak entered service on reference stardate 2/3012. She was eventually decommissioned as a training vessel on stardate 2/7705. (FASA RPG module: Star Trek: The Next Generation Officer's Manual)