Simplify the following text for a Grade 12 native English-speaking person.
Original: February 2011 there were 81 commissioned ships in the Royal Navy , including helicopter carriers , landing platform docks , ballistic missile submarines , nuclear fleet submarines , guided missile destroyers , frigates , mine counter-measures and patrol vessels . 16 vessels of the Royal Fleet Auxiliary ( RFA ) also contribute to the Royal Navy 's order-of-battle .
Simplified: The Royal Navy has 90 ships including aircraft carriers , submarines , minesweepers and patrol vessels as well as the ships of the Royal Fleet Auxiliary .