The Admirality system ranks your various ships by capability and allows you to send the ships you’ve unlocked on various missions. Higher-tier ships have better stat totals, but every ship also has an associated maintenance time needed after a given confrontation, meaning that higher-tier ships also have to sit in dock longer. There are also lengthy tours of duties available for the ships that allow players to pursue ongoing storylines. Check out the full dispatch for a clearer picture of what players can do when the Admirality system goes live.
Source: Official Site; thanks to The Grand Nagus for the tip!